diff --git a/packages/drfed/package.json b/packages/drfed/package.json
index da92e88..a67061f 100644
--- a/packages/drfed/package.json
+++ b/packages/drfed/package.json
@@ -60,18 +60,18 @@
   },
   "devDependencies": {
     "@types/node": "catalog:",
-    "@types/pg": "^8.20.0",
+    "@types/pg": "catalog:",
     "tsdown": "catalog:",
     "typescript": "catalog:"
   },
   "dependencies": {
     "@drfed/graphql": "workspace:*",
     "@drfed/models": "workspace:*",
-    "@electric-sql/pglite": "^0.5.3",
+    "@electric-sql/pglite": "catalog:",
     "@optique/core": "^1.1.0",
     "@optique/run": "^1.1.0",
     "drizzle-orm": "catalog:",
-    "pg": "^8.21.0",
+    "pg": "catalog:",
     "srvx": "^0.11.16"
   }
 }
diff --git a/packages/graphql/package.json b/packages/graphql/package.json
index 9dc27ea..8d06686 100644
--- a/packages/graphql/package.json
+++ b/packages/graphql/package.json
@@ -85,6 +85,7 @@
     "test": "node --test"
   },
   "devDependencies": {
+    "@electric-sql/pglite": "catalog:",
     "@types/node": "catalog:",
     "tsdown": "catalog:",
     "typescript": "catalog:"
diff --git a/packages/graphql/src/account.test.ts b/packages/graphql/src/account.test.ts
new file mode 100644
index 0000000..2ec82a4
--- /dev/null
+++ b/packages/graphql/src/account.test.ts
@@ -0,0 +1,195 @@
+// DrFed: A web-based platform for developing and debugging ActivityPub apps
+// Copyright (C) 2026 DrFed team
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+
+import { type Database, schema } from "@drfed/models";
+
+import { withTestHarness } from "./harness.test.ts";
+
+const accepted = new Date("2026-06-24T00:00:00.000Z");
+const created = new Date("2026-06-24T00:00:00.000Z");
+const expires = new Date("2026-07-24T00:00:00.000Z");
+const ok = 200;
+
+const accountId = "00000000-0000-4000-8000-000000000001";
+const memberId = "00000000-0000-4000-8000-000000000002";
+const pendingMemberId = "00000000-0000-4000-8000-000000000003";
+const acceptedInstanceId = "00000000-0000-4000-8000-000000000101";
+const pendingInstanceId = "00000000-0000-4000-8000-000000000102";
+
+const accountByUuidQuery = `
+  query Account($uuid: UUID!) {
+    accountByUuid(uuid: $uuid) {
+      uuid
+      email
+      name
+    }
+  }
+`;
+
+const accountInstancesQuery = `
+  query AccountInstances($uuid: UUID!) {
+    accountByUuid(uuid: $uuid) {
+      instances {
+        totalCount
+        edges {
+          created
+          accepted
+          admin
+          node {
+            uuid
+            slug
+          }
+        }
+      }
+    }
+  }
+`;
+
+const accountByUuidResponse = {
+  data: {
+    accountByUuid: {
+      uuid: accountId,
+      email: "owner@example.com",
+      name: "Owner",
+    },
+  },
+};
+
+const accountInstancesResponse = {
+  data: {
+    accountByUuid: {
+      instances: {
+        totalCount: 1,
+        edges: [
+          {
+            created: "2026-06-24T00:00:00.000Z",
+            accepted: "2026-06-24T00:00:00.000Z",
+            admin: true,
+            node: {
+              uuid: acceptedInstanceId,
+              slug: "test-instance",
+            },
+          },
+        ],
+      },
+    },
+  },
+};
+
+describe("accountByUuid", () => {
+  it("returns an account by UUID", async () => {
+    await withTestHarness(async ({ db, post }) => {
+      await seedAccounts(db);
+
+      const response = await post({
+        query: accountByUuidQuery,
+        variables: { uuid: accountId },
+      });
+
+      assert.equal(response.status, ok);
+      assert.deepEqual(await response.json(), accountByUuidResponse);
+    });
+  });
+});
+
+describe("Account.instances", () => {
+  it("returns the account's accepted instances", async () => {
+    await withTestHarness(async ({ db, post }) => {
+      await seedMembershipGraph(db);
+
+      const response = await post({
+        query: accountInstancesQuery,
+        variables: { uuid: accountId },
+      });
+
+      assert.equal(response.status, ok);
+      assert.deepEqual(await response.json(), accountInstancesResponse);
+    });
+  });
+});
+
+async function seedAccounts(db: Database): Promise<void> {
+  await db.insert(schema.accounts).values([
+    {
+      id: accountId,
+      email: "owner@example.com",
+      name: "Owner",
+      created,
+    },
+    {
+      id: memberId,
+      email: "member@example.com",
+      name: "Member",
+      created,
+    },
+    {
+      id: pendingMemberId,
+      email: "pending@example.com",
+      name: "Pending",
+      created,
+    },
+  ]);
+}
+
+async function seedMembershipGraph(db: Database): Promise<void> {
+  await seedAccounts(db);
+  await db.insert(schema.instances).values([
+    {
+      id: acceptedInstanceId,
+      slug: "test-instance",
+      created,
+      expires,
+    },
+    {
+      id: pendingInstanceId,
+      slug: "pending-instance",
+      created,
+      expires,
+    },
+  ]);
+  await db.insert(schema.instanceMembers).values([
+    {
+      accountId,
+      instanceId: acceptedInstanceId,
+      admin: true,
+      accepted,
+      created,
+    },
+    {
+      accountId: memberId,
+      instanceId: acceptedInstanceId,
+      admin: false,
+      accepted,
+      created,
+    },
+    {
+      accountId: pendingMemberId,
+      instanceId: acceptedInstanceId,
+      admin: false,
+      accepted: null,
+      created,
+    },
+    {
+      accountId,
+      instanceId: pendingInstanceId,
+      admin: false,
+      accepted: null,
+      created,
+    },
+  ]);
+}
diff --git a/packages/graphql/src/account.ts b/packages/graphql/src/account.ts
index 90f8fa1..0451807 100644
--- a/packages/graphql/src/account.ts
+++ b/packages/graphql/src/account.ts
@@ -13,37 +13,147 @@
 //
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import { instanceMembers } from "@drfed/models/schema";
+import { drizzleConnectionHelpers } from "@pothos/plugin-drizzle";
+import { and, eq, isNotNull } from "drizzle-orm/sql/expressions";
+
 import builder, { type DrFedObjectRef } from "./builder.ts";
+// oxlint-disable-next-line import/no-cycle
+import { Instance } from "./instance.ts";
 
 const AccountRef = builder.drizzleNode("accounts", {
+  name: "Account",
   description:
     "Represents an `Account` in the DrFed platform.  " +
     "Note that it differs from the ActivityPub `Actor`s that belong to `Instance`s.",
+  id: {
+    column(account) {
+      return account.id;
+    },
+    description: "The unique identifier of the `Account`.",
+  },
   fields: (t) => ({
-    created: t.expose("created", {
-      type: "DateTime",
-      description: "The date/time when the `Account` was created.",
+    uuid: t.expose("id", {
+      type: "UUID",
+      description: "The UUID of the `Account`.",
     }),
     email: t.expose("email", {
       type: "Email",
       description: "The email address of the `Account`.",
     }),
-    uuid: t.expose("id", {
-      type: "UUID",
-      description: "The UUID of the `Account`.",
+    name: t.exposeString("name", {
+      description: "The display name of the `Account`.",
+    }),
+    admin: t.exposeBoolean("admin", {
+      description: "Whether the `Account` has administrator privileges.",
+    }),
+    created: t.expose("created", {
+      type: "DateTime",
+      description: "The date/time when the `Account` was created.",
     }),
   }),
-  id: {
-    column(account) {
-      return account.id;
-    },
-    description: "The unique identifier of the `Account`.",
-  },
-  name: "Account",
 });
 
 export const Account: DrFedObjectRef = AccountRef;
 
+const accountInstancesConnection = drizzleConnectionHelpers(
+  builder,
+  "instanceMembers",
+  {
+    query: {
+      orderBy: { created: "desc" },
+    },
+    select(nestedSelection) {
+      return {
+        with: {
+          instance: nestedSelection(),
+        },
+        where: {
+          accepted: { isNotNull: true },
+        },
+      };
+    },
+    resolveNode(instanceMember) {
+      return instanceMember.instance!;
+    },
+  },
+);
+
+// oxlint-disable-next-line max-lines-per-function
+builder.drizzleObjectField(AccountRef, "instances", (t) =>
+  t.connection(
+    {
+      type: Instance,
+      description: "The `Instance`s that the `Account` belongs to.",
+      select(args, ctx, nestedSelection) {
+        return {
+          with: {
+            instanceMembers: accountInstancesConnection.getQuery(
+              args,
+              ctx,
+              nestedSelection,
+            ),
+          },
+        };
+      },
+      resolve(account, args, ctx) {
+        return {
+          ...accountInstancesConnection.resolve(
+            account.instanceMembers,
+            args,
+            ctx,
+            account,
+          ),
+          totalCount() {
+            return ctx.db.$count(
+              instanceMembers,
+              and(
+                eq(instanceMembers.accountId, account.id),
+                isNotNull(instanceMembers.accepted),
+              ),
+            );
+          },
+        };
+      },
+    },
+    {
+      fields(fb) {
+        return {
+          totalCount: fb.int({
+            description:
+              "The total number of `Instance`s that the `Account` belongs to." +
+              "Note that pending memberships are not counted.",
+            resolve(connection) {
+              return connection.totalCount();
+            },
+          }),
+        };
+      },
+    },
+    {
+      fields(fb) {
+        return {
+          created: fb.expose("created", {
+            type: "DateTime",
+            description:
+              "The date/time when the `Account` was added to the `Instance`.",
+          }),
+          accepted: fb.expose("accepted", {
+            type: "DateTime",
+            nullable: true,
+            description:
+              "The date/time when the `Account` accepted membership in the `Instance`.",
+          }),
+          admin: fb.exposeBoolean("admin", {
+            description:
+              "Whether the `Account` has administrator privileges in the `Instance`.",
+          }),
+        };
+      },
+    },
+  ),
+);
+
 builder.queryFields((t) => ({
   accountByUuid: t.drizzleField({
     args: {
diff --git a/packages/graphql/src/harness-smoke.test.ts b/packages/graphql/src/harness-smoke.test.ts
new file mode 100644
index 0000000..d1e0c8b
--- /dev/null
+++ b/packages/graphql/src/harness-smoke.test.ts
@@ -0,0 +1,42 @@
+// DrFed: A web-based platform for developing and debugging ActivityPub apps
+// Copyright (C) 2026 DrFed team
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+
+import { schema } from "@drfed/models";
+
+import { withTemporaryDatabase, withTestHarness } from "./harness.test.ts";
+
+describe("withTemporaryDatabase()", () => {
+  it("provides a migrated temporary database", async () => {
+    await withTemporaryDatabase(async (db) => {
+      const accounts = await db.select().from(schema.accounts);
+      assert.deepEqual(accounts, []);
+    });
+  });
+});
+
+describe("withTestHarness()", () => {
+  it("posts requests to a Yoga server", async () => {
+    await withTestHarness(async ({ post }) => {
+      const response = await post({ query: "{ __typename }" });
+      assert.ok(response.ok);
+      assert.deepEqual(await response.json(), {
+        data: { __typename: "Query" },
+      });
+    });
+  });
+});
diff --git a/packages/graphql/src/harness.test.ts b/packages/graphql/src/harness.test.ts
new file mode 100644
index 0000000..f679fca
--- /dev/null
+++ b/packages/graphql/src/harness.test.ts
@@ -0,0 +1,181 @@
+// DrFed: A web-based platform for developing and debugging ActivityPub apps
+// Copyright (C) 2026 DrFed team
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import { createYogaServer } from "@drfed/graphql";
+import type { ServerContext, UserContext } from "@drfed/graphql/builder";
+import { type Database, migrate, relations, schema } from "@drfed/models";
+import { PGlite } from "@electric-sql/pglite";
+import { drizzle } from "drizzle-orm/pglite";
+import type { YogaServerInstance } from "graphql-yoga";
+
+const testEndpoint = "http://drfed.test/graphql";
+
+/**
+ * The `fetch()` function exposed by the test Yoga server.
+ */
+export type TestFetch = YogaServerInstance<ServerContext, UserContext>["fetch"];
+
+/**
+ * A JSON GraphQL request body for {@link TestHarness.post}.
+ */
+export interface RequestBody {
+  /**
+   * The GraphQL operation source text.
+   */
+  readonly query: string;
+
+  /**
+   * Variables for the GraphQL operation.
+   */
+  readonly variables?: Readonly<Record<string, unknown>>;
+
+  /**
+   * The operation name to execute when `query` contains multiple operations.
+   */
+  readonly operationName?: string;
+}
+
+/**
+ * Utilities for testing the GraphQL server against a temporary database.
+ */
+export interface TestHarness {
+  /**
+   * The migrated temporary database.
+   */
+  readonly db: Database;
+
+  /**
+   * The test server's `fetch()` function, bound to the Yoga server instance.
+   */
+  readonly fetch: TestFetch;
+
+  /**
+   * The Yoga server instance under test.
+   */
+  readonly yoga: YogaServerInstance<ServerContext, UserContext>;
+
+  /**
+   * Sends a JSON `POST` request to the test server's GraphQL endpoint.
+   *
+   * @param body The GraphQL request body.
+   * @param init Additional request options.
+   * @returns The HTTP response returned by the Yoga server.
+   */
+  post(body: RequestBody, init?: RequestInit): Promise<Response>;
+}
+
+/**
+ * Runs a callback with a fresh in-memory PGlite database.
+ *
+ * The database is migrated before the callback is invoked, so every table in
+ * the current `@drfed/models` schema is available.  The underlying PGlite
+ * client is closed after the callback resolves or rejects.
+ *
+ * @example
+ * ```ts
+ * import assert from "node:assert/strict";
+ * import { it } from "node:test";
+ *
+ * import { schema } from "@drfed/models";
+ *
+ * import { withTemporaryDatabase } from "./harness.test.ts";
+ *
+ * it("queries accounts", async () => {
+ *   await withTemporaryDatabase(async (db) => {
+ *     const accounts = await db.select().from(schema.accounts);
+ *     assert.deepEqual(accounts, []);
+ *   });
+ * });
+ * ```
+ *
+ * @param callback A function that receives the migrated database.
+ * @returns The callback's resolved value.
+ */
+export async function withTemporaryDatabase<T>(
+  // oxlint-disable-next-line promise/prefer-await-to-callbacks
+  callback: (db: Database) => Promise<T> | T,
+): Promise<Awaited<T>> {
+  const client = new PGlite();
+  try {
+    await client.waitReady;
+    await migrate({ credentials: { driver: "pglite", client } });
+    const db: Database = drizzle({ client, relations, schema });
+    // oxlint-disable-next-line promise/prefer-await-to-callbacks
+    return await callback(db);
+  } finally {
+    await client.close();
+  }
+}
+
+/**
+ * Runs a callback with a Yoga server backed by a temporary database.
+ *
+ * The harness exposes the migrated database for seeding, the Yoga server for
+ * lower-level tests, and `post()` for JSON requests.
+ *
+ * @example
+ * ```ts
+ * import assert from "node:assert/strict";
+ * import { it } from "node:test";
+ *
+ * import { withTestHarness } from "./harness.test.ts";
+ *
+ * it("queries the schema", async () => {
+ *   await withTestHarness(async ({ post }) => {
+ *     const response = await post({ query: "{ __typename }" });
+ *
+ *     assert.equal(response.status, 200);
+ *     assert.deepEqual(await response.json(), {
+ *       data: { __typename: "Query" },
+ *     });
+ *   });
+ * });
+ * ```
+ *
+ * @param callback A function that receives the test harness.
+ * @returns The callback's resolved value.
+ */
+export async function withTestHarness<T>(
+  // oxlint-disable-next-line promise/prefer-await-to-callbacks
+  callback: (harness: TestHarness) => Promise<T> | T,
+): Promise<Awaited<T>> {
+  return await withTemporaryDatabase(async (db) => {
+    const yoga = createYogaServer(db);
+    const fetch: TestFetch = yoga.fetch.bind(yoga);
+
+    const harness: TestHarness = {
+      db,
+      fetch,
+      yoga,
+      post(body, init) {
+        const headers = new Headers(init?.headers);
+        if (!headers.has("content-type")) {
+          headers.set("content-type", "application/json");
+        }
+        return Promise.resolve(
+          fetch(testEndpoint, {
+            ...init,
+            body: JSON.stringify(body),
+            headers,
+            method: "POST",
+          }),
+        );
+      },
+    };
+
+    // oxlint-disable-next-line promise/prefer-await-to-callbacks
+    return await callback(harness);
+  });
+}
diff --git a/packages/graphql/src/instance.test.ts b/packages/graphql/src/instance.test.ts
new file mode 100644
index 0000000..5479556
--- /dev/null
+++ b/packages/graphql/src/instance.test.ts
@@ -0,0 +1,169 @@
+// DrFed: A web-based platform for developing and debugging ActivityPub apps
+// Copyright (C) 2026 DrFed team
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+
+import { type Database, schema } from "@drfed/models";
+
+import { withTestHarness } from "./harness.test.ts";
+
+const accepted = new Date("2026-06-24T00:00:00.000Z");
+const created = new Date("2026-06-24T00:00:00.000Z");
+const expires = new Date("2026-07-24T00:00:00.000Z");
+const ok = 200;
+
+const accountId = "00000000-0000-4000-8000-000000000001";
+const memberId = "00000000-0000-4000-8000-000000000002";
+const pendingMemberId = "00000000-0000-4000-8000-000000000003";
+const instanceId = "00000000-0000-4000-8000-000000000101";
+
+const instanceMembersQuery = `
+  query InstanceMembers($uuid: UUID!) {
+    accountByUuid(uuid: $uuid) {
+      instances {
+        edges {
+          node {
+            members {
+              totalCount
+              edges {
+                created
+                accepted
+                admin
+                node {
+                  uuid
+                  email
+                  name
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+`;
+
+const instanceMembersResponse = {
+  data: {
+    accountByUuid: {
+      instances: {
+        edges: [
+          {
+            node: {
+              members: {
+                totalCount: 2,
+                edges: [
+                  {
+                    created: "2026-06-24T00:00:00.000Z",
+                    accepted: "2026-06-24T00:00:00.000Z",
+                    admin: true,
+                    node: {
+                      uuid: accountId,
+                      email: "owner@example.com",
+                      name: "Owner",
+                    },
+                  },
+                  {
+                    created: "2026-06-24T00:00:00.000Z",
+                    accepted: "2026-06-24T00:00:00.000Z",
+                    admin: false,
+                    node: {
+                      uuid: memberId,
+                      email: "member@example.com",
+                      name: "Member",
+                    },
+                  },
+                ],
+              },
+            },
+          },
+        ],
+      },
+    },
+  },
+};
+
+describe("Instance.members", () => {
+  it("returns the instance's accepted members", async () => {
+    await withTestHarness(async ({ db, post }) => {
+      await seedInstanceMembers(db);
+
+      const response = await post({
+        query: instanceMembersQuery,
+        variables: { uuid: accountId },
+      });
+
+      assert.equal(response.status, ok);
+      assert.deepEqual(await response.json(), instanceMembersResponse);
+    });
+  });
+});
+
+// oxlint-disable-next-line max-lines-per-function
+async function seedInstanceMembers(db: Database): Promise<void> {
+  await db.insert(schema.accounts).values([
+    {
+      id: accountId,
+      email: "owner@example.com",
+      name: "Owner",
+      admin: false,
+      created,
+    },
+    {
+      id: memberId,
+      email: "member@example.com",
+      name: "Member",
+      admin: false,
+      created,
+    },
+    {
+      id: pendingMemberId,
+      email: "pending@example.com",
+      name: "Pending",
+      admin: false,
+      created,
+    },
+  ]);
+  await db.insert(schema.instances).values({
+    id: instanceId,
+    slug: "test-instance",
+    created,
+    expires,
+  });
+  await db.insert(schema.instanceMembers).values([
+    {
+      accountId,
+      instanceId,
+      admin: true,
+      accepted,
+      created,
+    },
+    {
+      accountId: memberId,
+      instanceId,
+      admin: false,
+      accepted,
+      created,
+    },
+    {
+      accountId: pendingMemberId,
+      instanceId,
+      admin: false,
+      accepted: null,
+      created,
+    },
+  ]);
+}
diff --git a/packages/graphql/src/instance.ts b/packages/graphql/src/instance.ts
index 9b49486..ebe5399 100644
--- a/packages/graphql/src/instance.ts
+++ b/packages/graphql/src/instance.ts
@@ -13,28 +13,136 @@
 //
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
+import { instanceMembers } from "@drfed/models/schema";
+import { drizzleConnectionHelpers } from "@pothos/plugin-drizzle";
+import { and, eq, isNotNull } from "drizzle-orm/sql/expressions";
+
+// oxlint-disable-next-line import/no-cycle
+import { Account } from "./account.ts";
 import builder, { type DrFedObjectRef } from "./builder.ts";
 
 const InstanceRef = builder.drizzleNode("instances", {
+  name: "Instance",
   description: "Represents an `Instance` in the DrFed platform.",
+  id: {
+    column(instance) {
+      return instance.id;
+    },
+    description: "The unique identifier of the `Instance`.",
+  },
   fields: (t) => ({
-    created: t.expose("created", {
-      type: "DateTime",
-      description: "The creation date/time of the `Instance`.",
+    uuid: t.expose("id", {
+      type: "UUID",
+      description: "The UUID of the `Instance`.",
     }),
+    slug: t.exposeString("slug"),
     expires: t.expose("expires", {
       type: "DateTime",
       description: "The expiration date/time of the `Instance`.",
     }),
-    slug: t.exposeString("slug"),
+    created: t.expose("created", {
+      type: "DateTime",
+      description: "The creation date/time of the `Instance`.",
+    }),
   }),
-  id: {
-    column(instance) {
-      return instance.id;
-    },
-    description: "The unique identifier of the `Instance`.",
-  },
-  name: "Instance",
 });
 
 export const Instance: DrFedObjectRef = InstanceRef;
+
+const instanceMembersConnection = drizzleConnectionHelpers(
+  builder,
+  "instanceMembers",
+  {
+    query: {
+      orderBy: { created: "desc" },
+    },
+    select(nestedSelection) {
+      return {
+        with: {
+          account: nestedSelection(),
+        },
+        where: {
+          accepted: { isNotNull: true },
+        },
+      };
+    },
+    resolveNode(instanceMember) {
+      return instanceMember.account;
+    },
+  },
+);
+
+// oxlint-disable-next-line max-lines-per-function
+builder.drizzleObjectField(InstanceRef, "members", (t) =>
+  t.connection(
+    {
+      type: Account,
+      description: "The `Account`s that belong to the `Instance`.",
+      select(args, ctx, nestedSelection) {
+        return {
+          with: {
+            instanceMembers: instanceMembersConnection.getQuery(
+              args,
+              ctx,
+              nestedSelection,
+            ),
+          },
+        };
+      },
+      resolve(instance, args, ctx) {
+        return {
+          ...instanceMembersConnection.resolve(
+            instance.instanceMembers,
+            args,
+            ctx,
+            instance,
+          ),
+          totalCount() {
+            return ctx.db.$count(
+              instanceMembers,
+              and(
+                eq(instanceMembers.instanceId, instance.id),
+                isNotNull(instanceMembers.accepted),
+              ),
+            );
+          },
+        };
+      },
+    },
+    {
+      fields(fb) {
+        return {
+          totalCount: fb.int({
+            description:
+              "The total number of `Account`s that belong to the `Instance`." +
+              "Note that pending members are not counted.",
+            resolve(connection) {
+              return connection.totalCount();
+            },
+          }),
+        };
+      },
+    },
+    {
+      fields(fb) {
+        return {
+          created: fb.expose("created", {
+            type: "DateTime",
+            description:
+              "The date/time when the `Account` was added to the `Instance`.",
+          }),
+          accepted: fb.expose("accepted", {
+            type: "DateTime",
+            nullable: true,
+            description:
+              "The date/time when the `Account` accepted membership in the `Instance`.",
+          }),
+          admin: fb.exposeBoolean("admin", {
+            description:
+              "Whether the `Account` has administrator privileges in the `Instance`.",
+          }),
+        };
+      },
+    },
+  ),
+);
diff --git a/packages/models/drizzle/20260623162238_dear_felicia_hardy/migration.sql b/packages/models/drizzle/20260623162238_dear_felicia_hardy/migration.sql
new file mode 100644
index 0000000..d377583
--- /dev/null
+++ b/packages/models/drizzle/20260623162238_dear_felicia_hardy/migration.sql
@@ -0,0 +1,5 @@
+ALTER TABLE "accounts" ADD COLUMN "name" varchar(100) NOT NULL;--> statement-breakpoint
+ALTER TABLE "instance_members" ADD COLUMN "accepted" timestamp with time zone;--> statement-breakpoint
+CREATE INDEX "instance_members_accountId_index" ON "instance_members" ("accountId") WHERE "accepted" IS NOT NULL;--> statement-breakpoint
+CREATE INDEX "instance_members_instanceId_index" ON "instance_members" ("instanceId") WHERE "accepted" IS NOT NULL;--> statement-breakpoint
+ALTER TABLE "accounts" ADD CONSTRAINT "accounts_name_check" CHECK (trim(both from "name") <> '');
\ No newline at end of file
diff --git a/packages/models/drizzle/20260623162238_dear_felicia_hardy/snapshot.json b/packages/models/drizzle/20260623162238_dear_felicia_hardy/snapshot.json
new file mode 100644
index 0000000..88ce77a
--- /dev/null
+++ b/packages/models/drizzle/20260623162238_dear_felicia_hardy/snapshot.json
@@ -0,0 +1,321 @@
+{
+  "version": "8",
+  "dialect": "postgres",
+  "id": "f04d695a-a99e-4bb9-be8d-190f9e7b67dc",
+  "prevIds": ["2cffbe98-208b-4301-ad32-8c2e3e74928f"],
+  "ddl": [
+    {
+      "isRlsEnabled": false,
+      "name": "accounts",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "isRlsEnabled": false,
+      "name": "instance_members",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "isRlsEnabled": false,
+      "name": "instances",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "id",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "varchar(255)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "email",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "varchar(100)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "name",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "accountId",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "instanceId",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": false,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "accepted",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "id",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "varchar(100)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "slug",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "expires",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "nameExplicit": false,
+      "columns": [
+        {
+          "value": "accountId",
+          "isExpression": false,
+          "asc": true,
+          "nullsFirst": false,
+          "opclass": null
+        }
+      ],
+      "isUnique": false,
+      "where": "\"accepted\" IS NOT NULL",
+      "with": "",
+      "method": "btree",
+      "concurrently": false,
+      "name": "instance_members_accountId_index",
+      "entityType": "indexes",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": [
+        {
+          "value": "instanceId",
+          "isExpression": false,
+          "asc": true,
+          "nullsFirst": false,
+          "opclass": null
+        }
+      ],
+      "isUnique": false,
+      "where": "\"accepted\" IS NOT NULL",
+      "with": "",
+      "method": "btree",
+      "concurrently": false,
+      "name": "instance_members_instanceId_index",
+      "entityType": "indexes",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["accountId"],
+      "schemaTo": "public",
+      "tableTo": "accounts",
+      "columnsTo": ["id"],
+      "onUpdate": "NO ACTION",
+      "onDelete": "NO ACTION",
+      "name": "instance_members_accountId_accounts_id_fkey",
+      "entityType": "fks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["instanceId"],
+      "schemaTo": "public",
+      "tableTo": "instances",
+      "columnsTo": ["id"],
+      "onUpdate": "NO ACTION",
+      "onDelete": "NO ACTION",
+      "name": "instance_members_instanceId_instances_id_fkey",
+      "entityType": "fks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "columns": ["instanceId", "accountId"],
+      "nameExplicit": false,
+      "name": "instance_members_pkey",
+      "entityType": "pks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "columns": ["id"],
+      "nameExplicit": false,
+      "name": "accounts_pkey",
+      "schema": "public",
+      "table": "accounts",
+      "entityType": "pks"
+    },
+    {
+      "columns": ["id"],
+      "nameExplicit": false,
+      "name": "instances_pkey",
+      "schema": "public",
+      "table": "instances",
+      "entityType": "pks"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["email"],
+      "nullsNotDistinct": false,
+      "name": "accounts_email_key",
+      "schema": "public",
+      "table": "accounts",
+      "entityType": "uniques"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["slug"],
+      "nullsNotDistinct": false,
+      "name": "instances_slug_key",
+      "schema": "public",
+      "table": "instances",
+      "entityType": "uniques"
+    },
+    {
+      "value": "\"email\" ~ '^[^@]+@[^@]+\\.[^@]+$'",
+      "name": "accounts_email_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "value": "trim(both from \"name\") <> ''",
+      "name": "accounts_name_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "value": "\"slug\" ~ '^[a-z0-9-]{4,100}$'",
+      "name": "instances_slug_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "value": "\"expires\" < (\"created\" + INTERVAL '1 year')",
+      "name": "instances_expires_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "instances"
+    }
+  ],
+  "renames": []
+}
diff --git a/packages/models/drizzle/20260624094817_lethal_sinister_six/migration.sql b/packages/models/drizzle/20260624094817_lethal_sinister_six/migration.sql
new file mode 100644
index 0000000..3237c9f
--- /dev/null
+++ b/packages/models/drizzle/20260624094817_lethal_sinister_six/migration.sql
@@ -0,0 +1,2 @@
+ALTER TABLE "accounts" ADD COLUMN "admin" boolean DEFAULT false NOT NULL;--> statement-breakpoint
+ALTER TABLE "instance_members" ADD COLUMN "admin" boolean DEFAULT false NOT NULL;
\ No newline at end of file
diff --git a/packages/models/drizzle/20260624094817_lethal_sinister_six/snapshot.json b/packages/models/drizzle/20260624094817_lethal_sinister_six/snapshot.json
new file mode 100644
index 0000000..5db731b
--- /dev/null
+++ b/packages/models/drizzle/20260624094817_lethal_sinister_six/snapshot.json
@@ -0,0 +1,347 @@
+{
+  "version": "8",
+  "dialect": "postgres",
+  "id": "15845826-f718-42c3-85f2-fed368f261f4",
+  "prevIds": ["f04d695a-a99e-4bb9-be8d-190f9e7b67dc"],
+  "ddl": [
+    {
+      "isRlsEnabled": false,
+      "name": "accounts",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "isRlsEnabled": false,
+      "name": "instance_members",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "isRlsEnabled": false,
+      "name": "instances",
+      "entityType": "tables",
+      "schema": "public"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "id",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "varchar(255)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "email",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "varchar(100)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "name",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "boolean",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "false",
+      "generated": null,
+      "identity": null,
+      "name": "admin",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "accountId",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "instanceId",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "boolean",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "false",
+      "generated": null,
+      "identity": null,
+      "name": "admin",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": false,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "accepted",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "type": "uuid",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "id",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "varchar(100)",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "slug",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": null,
+      "generated": null,
+      "identity": null,
+      "name": "expires",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "type": "timestamp with time zone",
+      "typeSchema": null,
+      "notNull": true,
+      "dimensions": 0,
+      "default": "CURRENT_TIMESTAMP",
+      "generated": null,
+      "identity": null,
+      "name": "created",
+      "entityType": "columns",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "nameExplicit": false,
+      "columns": [
+        {
+          "value": "accountId",
+          "isExpression": false,
+          "asc": true,
+          "nullsFirst": false,
+          "opclass": null
+        }
+      ],
+      "isUnique": false,
+      "where": "\"accepted\" IS NOT NULL",
+      "with": "",
+      "method": "btree",
+      "concurrently": false,
+      "name": "instance_members_accountId_index",
+      "entityType": "indexes",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": [
+        {
+          "value": "instanceId",
+          "isExpression": false,
+          "asc": true,
+          "nullsFirst": false,
+          "opclass": null
+        }
+      ],
+      "isUnique": false,
+      "where": "\"accepted\" IS NOT NULL",
+      "with": "",
+      "method": "btree",
+      "concurrently": false,
+      "name": "instance_members_instanceId_index",
+      "entityType": "indexes",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["accountId"],
+      "schemaTo": "public",
+      "tableTo": "accounts",
+      "columnsTo": ["id"],
+      "onUpdate": "NO ACTION",
+      "onDelete": "NO ACTION",
+      "name": "instance_members_accountId_accounts_id_fkey",
+      "entityType": "fks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["instanceId"],
+      "schemaTo": "public",
+      "tableTo": "instances",
+      "columnsTo": ["id"],
+      "onUpdate": "NO ACTION",
+      "onDelete": "NO ACTION",
+      "name": "instance_members_instanceId_instances_id_fkey",
+      "entityType": "fks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "columns": ["instanceId", "accountId"],
+      "nameExplicit": false,
+      "name": "instance_members_pkey",
+      "entityType": "pks",
+      "schema": "public",
+      "table": "instance_members"
+    },
+    {
+      "columns": ["id"],
+      "nameExplicit": false,
+      "name": "accounts_pkey",
+      "schema": "public",
+      "table": "accounts",
+      "entityType": "pks"
+    },
+    {
+      "columns": ["id"],
+      "nameExplicit": false,
+      "name": "instances_pkey",
+      "schema": "public",
+      "table": "instances",
+      "entityType": "pks"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["email"],
+      "nullsNotDistinct": false,
+      "name": "accounts_email_key",
+      "schema": "public",
+      "table": "accounts",
+      "entityType": "uniques"
+    },
+    {
+      "nameExplicit": false,
+      "columns": ["slug"],
+      "nullsNotDistinct": false,
+      "name": "instances_slug_key",
+      "schema": "public",
+      "table": "instances",
+      "entityType": "uniques"
+    },
+    {
+      "value": "\"email\" ~ '^[^@]+@[^@]+\\.[^@]+$'",
+      "name": "accounts_email_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "value": "trim(both from \"name\") <> ''",
+      "name": "accounts_name_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "accounts"
+    },
+    {
+      "value": "\"slug\" ~ '^[a-z0-9-]{4,100}$'",
+      "name": "instances_slug_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "instances"
+    },
+    {
+      "value": "\"expires\" < (\"created\" + INTERVAL '1 year')",
+      "name": "instances_expires_check",
+      "entityType": "checks",
+      "schema": "public",
+      "table": "instances"
+    }
+  ],
+  "renames": []
+}
diff --git a/packages/models/package.json b/packages/models/package.json
index 4a5095f..3133911 100644
--- a/packages/models/package.json
+++ b/packages/models/package.json
@@ -92,14 +92,14 @@
   },
   "devDependencies": {
     "@types/node": "catalog:",
-    "@types/pg": "^8.20.0",
+    "@types/pg": "catalog:",
     "drizzle-kit": "1.0.0-beta.22",
     "tsdown": "catalog:",
     "typescript": "catalog:"
   },
   "dependencies": {
-    "@electric-sql/pglite": "^0.5.3",
+    "@electric-sql/pglite": "catalog:",
     "drizzle-orm": "catalog:",
-    "pg": "^8.21.0"
+    "pg": "catalog:"
   }
 }
diff --git a/packages/models/src/relations.ts b/packages/models/src/relations.ts
index da56125..f730edd 100644
--- a/packages/models/src/relations.ts
+++ b/packages/models/src/relations.ts
@@ -22,6 +22,18 @@ export const relations = defineRelations(schema, (r) => ({
     instances: r.many.instances({
       from: r.accounts.id.through(r.instanceMembers.accountId),
       to: r.instances.id.through(r.instanceMembers.instanceId),
+      // Drizzle ORM currently does not support many-to-many relationships with
+      // additional filters on the junction table.  So we need to specify
+      // filter `accepted IS NOT NULL` everywhere we query for instances of
+      // an account (sigh).  See also the below issue:
+      // https://github.com/drizzle-team/drizzle-orm/issues/5343
+    }),
+    instanceMembers: r.many.instanceMembers({
+      from: r.accounts.id,
+      to: r.instanceMembers.accountId,
+      where: {
+        accepted: { isNotNull: true },
+      },
     }),
   },
   instanceMembers: {
@@ -38,6 +50,18 @@ export const relations = defineRelations(schema, (r) => ({
     members: r.many.accounts({
       from: r.instances.id.through(r.instanceMembers.instanceId),
       to: r.accounts.id.through(r.instanceMembers.accountId),
+      // Drizzle ORM currently does not support many-to-many relationships with
+      // additional filters on the junction table.  So we need to specify
+      // filter `accepted IS NOT NULL` everywhere we query for members of
+      // an instance (sigh).  See also the below issue:
+      // https://github.com/drizzle-team/drizzle-orm/issues/5343
+    }),
+    instanceMembers: r.many.instanceMembers({
+      from: r.instances.id,
+      to: r.instanceMembers.instanceId,
+      where: {
+        accepted: { isNotNull: true },
+      },
     }),
   },
 }));
diff --git a/packages/models/src/schema.ts b/packages/models/src/schema.ts
index 35ef9eb..38ba83c 100644
--- a/packages/models/src/schema.ts
+++ b/packages/models/src/schema.ts
@@ -15,7 +15,9 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 import { sql } from "drizzle-orm";
 import {
+  boolean,
   check,
+  index,
   pgTable,
   primaryKey,
   timestamp,
@@ -29,17 +31,20 @@ import {
 export const accounts = pgTable(
   "accounts",
   {
+    id: uuid().primaryKey(),
+    email: varchar({ length: 255 }).notNull().unique(),
+    name: varchar({ length: 100 }).notNull(),
+    admin: boolean().notNull().default(false),
     created: timestamp({ withTimezone: true })
       .notNull()
       .default(sql`CURRENT_TIMESTAMP`),
-    email: varchar({ length: 255 }).notNull().unique(),
-    id: uuid().primaryKey(),
   },
   (table) => [
     check(
       "accounts_email_check",
       sql`${table.email} ~ '^[^@]+@[^@]+\\.[^@]+$'`,
     ),
+    check("accounts_name_check", sql`trim(both from ${table.name}) <> ''`),
   ],
 );
 
@@ -52,12 +57,12 @@ export type NewAccount = typeof accounts.$inferInsert;
 export const instances = pgTable(
   "instances",
   {
+    id: uuid().primaryKey(),
+    slug: varchar({ length: 100 }).notNull().unique(),
+    expires: timestamp({ withTimezone: true }).notNull(),
     created: timestamp({ withTimezone: true })
       .notNull()
       .default(sql`CURRENT_TIMESTAMP`),
-    expires: timestamp({ withTimezone: true }).notNull(),
-    id: uuid().primaryKey(),
-    slug: varchar({ length: 100 }).notNull().unique(),
   },
   (table) => [
     check("instances_slug_check", sql`${table.slug} ~ '^[a-z0-9-]{4,100}$'`),
@@ -73,6 +78,8 @@ export type NewInstance = typeof instances.$inferInsert;
 
 /**
  * The association table between instances and its member accounts.
+ * Note that it also contains the just invited members, which are not yet
+ * accepted.  The `accepted` field is `NULL` for those members.
  */
 export const instanceMembers = pgTable(
   "instance_members",
@@ -80,14 +87,24 @@ export const instanceMembers = pgTable(
     accountId: uuid()
       .notNull()
       .references(() => accounts.id),
-    created: timestamp({ withTimezone: true })
-      .notNull()
-      .default(sql`CURRENT_TIMESTAMP`),
     instanceId: uuid()
       .notNull()
       .references(() => instances.id),
+    admin: boolean().notNull().default(false),
+    accepted: timestamp({ withTimezone: true }),
+    created: timestamp({ withTimezone: true })
+      .notNull()
+      .default(sql`CURRENT_TIMESTAMP`),
   },
-  (table) => [primaryKey({ columns: [table.instanceId, table.accountId] })],
+  (table) => [
+    primaryKey({ columns: [table.instanceId, table.accountId] }),
+    index()
+      .on(table.accountId)
+      .where(sql`${table.accepted} IS NOT NULL`),
+    index()
+      .on(table.instanceId)
+      .where(sql`${table.accepted} IS NOT NULL`),
+  ],
 );
 
 export type InstanceMember = typeof instanceMembers.$inferSelect;
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index fdcf570..296231c 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -6,12 +6,21 @@ settings:
 
 catalogs:
   default:
+    '@electric-sql/pglite':
+      specifier: ^0.5.3
+      version: 0.5.3
     '@types/node':
       specifier: ^26.0.0
       version: 26.0.0
+    '@types/pg':
+      specifier: ^8.20.0
+      version: 8.20.0
     drizzle-orm:
       specifier: 1.0.0-beta.22
       version: 1.0.0-beta.22
+    pg:
+      specifier: ^8.21.0
+      version: 8.21.0
     tsdown:
       specifier: ^0.22.3
       version: 0.22.3
@@ -30,7 +39,7 @@ importers:
         specifier: workspace:*
         version: link:../models
       '@electric-sql/pglite':
-        specifier: ^0.5.3
+        specifier: 'catalog:'
         version: 0.5.3
       '@optique/core':
         specifier: ^1.1.0
@@ -42,7 +51,7 @@ importers:
         specifier: 'catalog:'
         version: 1.0.0-beta.22(@electric-sql/pglite@0.5.3)(@types/pg@8.20.0)(pg@8.21.0)
       pg:
-        specifier: ^8.21.0
+        specifier: 'catalog:'
         version: 8.21.0
       srvx:
         specifier: ^0.11.16
@@ -52,7 +61,7 @@ importers:
         specifier: 'catalog:'
         version: 26.0.0
       '@types/pg':
-        specifier: ^8.20.0
+        specifier: 'catalog:'
         version: 8.20.0
       tsdown:
         specifier: 'catalog:'
@@ -88,6 +97,9 @@ importers:
         specifier: ^5.21.2
         version: 5.21.2(graphql@16.14.2)
     devDependencies:
+      '@electric-sql/pglite':
+        specifier: 'catalog:'
+        version: 0.5.3
       '@types/node':
         specifier: 'catalog:'
         version: 26.0.0
@@ -101,20 +113,20 @@ importers:
   packages/models:
     dependencies:
       '@electric-sql/pglite':
-        specifier: ^0.5.3
+        specifier: 'catalog:'
         version: 0.5.3
       drizzle-orm:
         specifier: 'catalog:'
         version: 1.0.0-beta.22(@electric-sql/pglite@0.5.3)(@types/pg@8.20.0)(pg@8.21.0)
       pg:
-        specifier: ^8.21.0
+        specifier: 'catalog:'
         version: 8.21.0
     devDependencies:
       '@types/node':
         specifier: 'catalog:'
         version: 26.0.0
       '@types/pg':
-        specifier: ^8.20.0
+        specifier: 'catalog:'
         version: 8.20.0
       drizzle-kit:
         specifier: 1.0.0-beta.22
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
index b4b4756..cb61ad7 100644
--- a/pnpm-workspace.yaml
+++ b/pnpm-workspace.yaml
@@ -5,7 +5,10 @@ allowBuilds:
   esbuild: true
 
 catalog:
+  "@electric-sql/pglite": ^0.5.3
   "@types/node": ^26.0.0
+  "@types/pg": ^8.20.0
   drizzle-orm: 1.0.0-beta.22
+  pg: ^8.21.0
   tsdown: ^0.22.3
   typescript: ^6.0.3