diff --git a/package.json b/package.json
index be06fed..ecd61b3 100644
--- a/package.json
+++ b/package.json
@@ -46,6 +46,8 @@
     "@koa/cors": "^4.0.0",
     "@koa/router": "^12.0.0",
     "@solid/access-token-verifier": "^2.0.5",
+    "ajv": "^8.12.0",
+    "ajv-formats": "^2.1.1",
     "bcryptjs": "^2.4.3",
     "cross-fetch": "^4.0.0",
     "dotenv": "^16.0.0",
diff --git a/src/app.ts b/src/app.ts
index ca15d0d..20669e7 100644
--- a/src/app.ts
+++ b/src/app.ts
@@ -11,6 +11,7 @@ import {
 import { getStatus } from './controllers/status'
 import { webhookReceiver } from './controllers/webhookReceiver'
 import { solidAuth } from './middlewares/solidAuth'
+import { validateBody } from './middlewares/validate'
 
 const app = new Koa()
 const router = new Router()
@@ -20,7 +21,24 @@ router
     ctx.response.body =
       'Hello world! This is a Solid email notifier. Read more at https://github.com/openHospitalityNetwork/solid-email-notifications'
   })
-  .post('/inbox', solidAuth, initializeIntegration)
+  .post(
+    '/inbox',
+    solidAuth,
+    validateBody({
+      type: 'object',
+      properties: {
+        '@context': { const: 'https://www.w3.org/ns/activitystreams' },
+        '@id': { type: 'string' },
+        '@type': { const: 'Add' },
+        actor: { type: 'string', format: 'uri' },
+        object: { type: 'string', format: 'uri' },
+        target: { type: 'string', format: 'email' },
+      },
+      required: ['@context', '@type', 'actor', 'object', 'target'],
+      additionalProperties: false,
+    }),
+    initializeIntegration,
+  )
   .get('/verify-email', checkVerificationLink, finishIntegration)
   .post('/webhook-receiver', webhookReceiver)
   .get('/status', solidAuth, getStatus)
diff --git a/src/middlewares/solidAuth.ts b/src/middlewares/solidAuth.ts
index 4cbb42a..4f1d99c 100644
--- a/src/middlewares/solidAuth.ts
+++ b/src/middlewares/solidAuth.ts
@@ -26,7 +26,7 @@ export const solidAuth: Middleware = async (ctx, next) => {
       (error as Error).message
     }`
 
-    ctx.throw(401, { error: message })
+    ctx.throw(401, message)
   }
 
   // on success continue
diff --git a/src/middlewares/validate.ts b/src/middlewares/validate.ts
new file mode 100644
index 0000000..59b78ca
--- /dev/null
+++ b/src/middlewares/validate.ts
@@ -0,0 +1,20 @@
+import addFormats from 'ajv-formats'
+import Ajv2020 from 'ajv/dist/2020'
+import type { Middleware } from 'koa'
+
+const ajv = new Ajv2020({ allErrors: true })
+addFormats(ajv)
+
+export const validateBody =
+  (schema: Parameters<typeof ajv.compile>[0]): Middleware =>
+  async (ctx, next) => {
+    const validate = ajv.compile(schema)
+    const isValid = validate(ctx.request.body)
+
+    if (isValid) return await next()
+    else {
+      ctx.response.status = 400
+      ctx.response.type = 'json'
+      ctx.response.body = validate.errors
+    }
+  }
diff --git a/src/test/integration-start.spec.ts b/src/test/integration-start.spec.ts
index 142410a..9b25b0e 100644
--- a/src/test/integration-start.spec.ts
+++ b/src/test/integration-start.spec.ts
@@ -51,6 +51,26 @@ describe('Mailer integration via /inbox', () => {
     expect(response.status).to.equal(200)
   })
 
+  it('[invalid request body] should respond with 400', async () => {
+    const response = await authenticatedFetch(`${baseUrl}/inbox`, {
+      method: 'post',
+      headers: {
+        'content-type':
+          'application/ld+json;profile="https://www.w3.org/ns/activitystreams"',
+      },
+      body: JSON.stringify({
+        '@context': 'https://www.w3.org/ns/activitystrams',
+        '@id': '',
+        '@type': 'ads',
+        actor: 'asdf',
+        object: '/inbox',
+        target: 'yay',
+      }),
+    })
+
+    expect(response.status).to.equal(400)
+  })
+
   context('person not signed in', () => {
     it('should respond with 401', async () => {
       const response = await fetch(`${baseUrl}/inbox`, {
@@ -89,16 +109,6 @@ describe('Mailer integration via /inbox', () => {
     })
   })
 
-  it('should check that the person requesting is the authenticated person', async () => {
-    const response = await authenticatedFetch(`${baseUrl}/inbox`, {
-      method: 'post',
-      headers: { 'content-type': 'application/ld+json' },
-      body: JSON.stringify({}),
-    })
-
-    expect(response.status).to.equal(403)
-  })
-
   it(
     'should check that the inbox belongs to the person requesting subscription',
   )
diff --git a/yarn.lock b/yarn.lock
index ecb187a..cc9d414 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3089,6 +3089,13 @@ aggregate-error@^3.0.0:
     clean-stack "^2.0.0"
     indent-string "^4.0.0"
 
+ajv-formats@^2.1.1:
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/ajv-formats/-/ajv-formats-2.1.1.tgz#6e669400659eb74973bbf2e33327180a0996b520"
+  integrity sha512-Wx0Kx52hxE7C18hkMEggYlEifqWZtYaRgouJor+WMdPnQyEK13vgEWyVNup7SoeeoLMsr4kf5h6dOW11I15MUA==
+  dependencies:
+    ajv "^8.0.0"
+
 ajv@^6.10.0, ajv@^6.12.4:
   version "6.12.6"
   resolved "https://registry.yarnpkg.com/ajv/-/ajv-6.12.6.tgz#baf5a62e802b07d977034586f8c3baf5adf26df4"
@@ -3099,6 +3106,16 @@ ajv@^6.10.0, ajv@^6.12.4:
     json-schema-traverse "^0.4.1"
     uri-js "^4.2.2"
 
+ajv@^8.0.0, ajv@^8.12.0:
+  version "8.12.0"
+  resolved "https://registry.yarnpkg.com/ajv/-/ajv-8.12.0.tgz#d1a0527323e22f53562c567c00991577dfbe19d1"
+  integrity sha512-sRu1kpcO9yLtYxBKvqfTeh9KzZEwO3STyX1HT+4CaDzC6HpTGYhIhPIzj9XuKU7KYDwnaeh5hcOwjy1QuJzBPA==
+  dependencies:
+    fast-deep-equal "^3.1.1"
+    json-schema-traverse "^1.0.0"
+    require-from-string "^2.0.2"
+    uri-js "^4.2.2"
+
 ansi-colors@4.1.1:
   version "4.1.1"
   resolved "https://registry.yarnpkg.com/ansi-colors/-/ansi-colors-4.1.1.tgz#cbb9ae256bf750af1eab344f229aa27fe94ba348"
@@ -5109,6 +5126,11 @@ json-schema-traverse@^0.4.1:
   resolved "https://registry.yarnpkg.com/json-schema-traverse/-/json-schema-traverse-0.4.1.tgz#69f6a87d9513ab8bb8fe63bdb0979c448e684660"
   integrity sha512-xbbCH5dCYU5T8LcEhhuh7HJ88HXuW3qsI3Y0zOZFKfZEHcpWiHU/Jxzk629Brsab/mMiHQti9wMP+845RPe3Vg==
 
+json-schema-traverse@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/json-schema-traverse/-/json-schema-traverse-1.0.0.tgz#ae7bcb3656ab77a73ba5c49bf654f38e6b6860e2"
+  integrity sha512-NM8/P9n3XjXhIZn1lLhkFaACTOURQXjWhV4BA/RnOv8xvgqtqpAX9IO4mRQxSx1Rlo4tqzeqb0sOlruaOy3dug==
+
 json-stable-stringify-without-jsonify@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/json-stable-stringify-without-jsonify/-/json-stable-stringify-without-jsonify-1.0.1.tgz#9db7b59496ad3f3cfef30a75142d2d930ad72651"
@@ -6473,6 +6495,11 @@ require-directory@^2.1.1:
   resolved "https://registry.yarnpkg.com/require-directory/-/require-directory-2.1.1.tgz#8c64ad5fd30dab1c976e2344ffe7f792a6a6df42"
   integrity sha512-fGxEI7+wsG9xrvdjsrlmL22OMTTiHRwAMroiEeMgq8gzoLC/PQr7RsRDSTLUg/bZAZtF+TVIkHc6/4RIKrui+Q==
 
+require-from-string@^2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/require-from-string/-/require-from-string-2.0.2.tgz#89a7fdd938261267318eafe14f9c32e598c36909"
+  integrity sha512-Xf0nWe6RseziFMu+Ap9biiUbmplq6S9/p+7w7YXP/JBHhrUDDUhwa+vANyubuqfZWTveU//DYVGsDG7RKL/vEw==
+
 requires-port@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/requires-port/-/requires-port-1.0.0.tgz#925d2601d39ac485e091cf0da5c6e694dc3dcaff"