diff --git a/api/src/main/java/com/oviva/spicegen/api/CheckPermission.java b/api/src/main/java/com/oviva/spicegen/api/CheckPermission.java
index 2052674..321e474 100644
--- a/api/src/main/java/com/oviva/spicegen/api/CheckPermission.java
+++ b/api/src/main/java/com/oviva/spicegen/api/CheckPermission.java
@@ -1,92 +1,30 @@
 package com.oviva.spicegen.api;
 
-import java.util.Objects;
+import com.oviva.spicegen.api.internal.CheckPermissionImpl;
 
-public final class CheckPermission {
+public interface CheckPermission {
 
-  private final ObjectRef resource;
-  private final String permission;
-  private final SubjectRef subject;
-
-  private final Consistency consistency;
-
-  private CheckPermission(Builder builder) {
-    resource = builder.resource;
-    permission = builder.permission;
-    subject = builder.subject;
-    consistency = builder.consistency;
-  }
-
-  public static Builder newBuilder() {
-    return new Builder();
-  }
-
-  public ObjectRef resource() {
-    return resource;
-  }
-
-  public String permission() {
-    return permission;
-  }
-
-  public SubjectRef subject() {
-    return subject;
+  static Builder newBuilder() {
+    return new CheckPermissionImpl.Builder();
   }
 
-  public Consistency consistency() {
-    return consistency;
-  }
+  ObjectRef resource();
 
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    var that = (CheckPermission) o;
-    return Objects.equals(resource, that.resource)
-        && Objects.equals(permission, that.permission)
-        && Objects.equals(subject, that.subject)
-        && Objects.equals(consistency, that.consistency);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(resource, permission, subject, consistency);
-  }
+  String permission();
 
-  public static final class Builder {
-    private ObjectRef resource;
-    private String permission;
-    private SubjectRef subject;
-    private Consistency consistency = Consistency.fullyConsistent();
+  SubjectRef subject();
 
-    private Builder() {}
+  Consistency consistency();
 
-    public Builder resource(ObjectRef resource) {
-      this.resource = resource;
-      return this;
-    }
+  interface Builder {
+    Builder resource(ObjectRef resource);
 
-    public Builder permission(String permission) {
-      this.permission = permission;
-      return this;
-    }
+    Builder permission(String permission);
 
-    public Builder subject(SubjectRef subject) {
-      this.subject = subject;
-      return this;
-    }
+    Builder subject(SubjectRef subject);
 
-    public Builder consistency(Consistency consistency) {
-      this.consistency = consistency;
-      return this;
-    }
+    Builder consistency(Consistency consistency);
 
-    public CheckPermission build() {
-      return new CheckPermission(this);
-    }
+    CheckPermission build();
   }
 }
diff --git a/api/src/main/java/com/oviva/spicegen/api/Consistency.java b/api/src/main/java/com/oviva/spicegen/api/Consistency.java
index b0aa6c5..e642910 100644
--- a/api/src/main/java/com/oviva/spicegen/api/Consistency.java
+++ b/api/src/main/java/com/oviva/spicegen/api/Consistency.java
@@ -1,57 +1,25 @@
 package com.oviva.spicegen.api;
 
-import java.util.Objects;
+import com.oviva.spicegen.api.internal.ConsistencyImpl;
 
-public final class Consistency {
+public interface Consistency {
 
-  private static Consistency FULLY_CONSISTENT = new Consistency(Requirement.FULLY_CONSISTENT, null);
-  private final Requirement requirement;
+  String consistencyToken();
 
-  private final String consistencyToken;
+  Requirement requirement();
 
-  private Consistency(Requirement requirement, String consistencyToken) {
-    this.requirement = requirement;
-    this.consistencyToken = consistencyToken;
+  static Consistency fullyConsistent() {
+    return ConsistencyImpl.fullyConsistent();
   }
 
-  public String consistencyToken() {
-    return consistencyToken;
-  }
-
-  public Requirement requirement() {
-    return requirement;
-  }
-
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    var that = (Consistency) o;
-    return requirement == that.requirement
-        && Objects.equals(consistencyToken, that.consistencyToken);
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(requirement, consistencyToken);
-  }
-
-  public static Consistency fullyConsistent() {
-    return FULLY_CONSISTENT;
-  }
-
-  public static Consistency atLeastAsFreshAs(String consistencyToken) {
+  static Consistency atLeastAsFreshAs(String consistencyToken) {
     if (consistencyToken == null) {
-      return FULLY_CONSISTENT;
+      return ConsistencyImpl.fullyConsistent();
     }
-    return new Consistency(Requirement.AT_LEAST_AS_FRESH, consistencyToken);
+    return new ConsistencyImpl(Consistency.Requirement.AT_LEAST_AS_FRESH, consistencyToken);
   }
 
-  public enum Requirement {
+  enum Requirement {
     FULLY_CONSISTENT,
     AT_LEAST_AS_FRESH
   }
diff --git a/api/src/main/java/com/oviva/spicegen/api/Precondition.java b/api/src/main/java/com/oviva/spicegen/api/Precondition.java
index c3b5def..5004129 100644
--- a/api/src/main/java/com/oviva/spicegen/api/Precondition.java
+++ b/api/src/main/java/com/oviva/spicegen/api/Precondition.java
@@ -1,63 +1,36 @@
 package com.oviva.spicegen.api;
 
-public final class Precondition {
+import com.oviva.spicegen.api.internal.PreconditionImpl;
 
-  private final Condition condition;
-  private final RelationshipFilter filter;
+public interface Precondition {
 
-  private Precondition(Builder builder) {
-    condition = builder.condition;
-    filter = builder.filter;
-  }
+  Condition condition();
 
-  public static Precondition mustMatch(RelationshipFilter filter) {
-    return new Precondition(Condition.MUST_MATCH, filter);
-  }
+  RelationshipFilter filter();
 
-  public static Precondition mustNotMatch(RelationshipFilter filter) {
-    return new Precondition(Condition.MUST_NOT_MATCH, filter);
+  static Precondition mustMatch(RelationshipFilter filter) {
+    return new PreconditionImpl(Condition.MUST_MATCH, filter);
   }
 
-  public static Builder newBuilder() {
-    return new Builder();
+  static Precondition mustNotMatch(RelationshipFilter filter) {
+    return new PreconditionImpl(Condition.MUST_NOT_MATCH, filter);
   }
 
-  private Precondition(Condition condition, RelationshipFilter filter) {
-    this.condition = condition;
-    this.filter = filter;
-  }
-
-  public Condition condition() {
-    return condition;
-  }
-
-  public RelationshipFilter filter() {
-    return filter;
-  }
-
-  public enum Condition {
+  enum Condition {
     MUST_MATCH,
     MUST_NOT_MATCH
   }
 
-  public static final class Builder {
-    private Condition condition;
-    private RelationshipFilter filter;
+  static Builder newBuilder() {
+    return new PreconditionImpl.Builder();
+  }
 
-    private Builder() {}
+  interface Builder {
 
-    public Builder condition(Condition val) {
-      condition = val;
-      return this;
-    }
+    Precondition.Builder condition(Condition condition);
 
-    public Builder filter(RelationshipFilter val) {
-      filter = val;
-      return this;
-    }
+    Precondition.Builder filter(RelationshipFilter filter);
 
-    public Precondition build() {
-      return new Precondition(this);
-    }
+    Precondition build();
   }
 }
diff --git a/api/src/main/java/com/oviva/spicegen/api/RelationshipFilter.java b/api/src/main/java/com/oviva/spicegen/api/RelationshipFilter.java
index 423cb04..8ec17ab 100644
--- a/api/src/main/java/com/oviva/spicegen/api/RelationshipFilter.java
+++ b/api/src/main/java/com/oviva/spicegen/api/RelationshipFilter.java
@@ -1,137 +1,56 @@
 package com.oviva.spicegen.api;
 
+import com.oviva.spicegen.api.internal.RelationshipFilterImpl;
 import java.util.Optional;
 
-public final class RelationshipFilter {
+public interface RelationshipFilter {
 
-  private final String resourceKind;
-
-  /** optional */
-  private final String resourceId;
-
-  /** optional */
-  private final String relation;
-
-  /** optional */
-  private final SubjectFilter subjectFilter;
-
-  private RelationshipFilter(Builder builder) {
-    resourceKind = builder.resourceKind;
-    resourceId = builder.resourceId;
-    relation = builder.relation;
-    subjectFilter = builder.subjectFilter;
+  static Builder newBuilder() {
+    return new RelationshipFilterImpl.Builder();
   }
 
-  public static Builder newBuilder() {
-    return new Builder();
-  }
-
-  public String resourceKind() {
-    return resourceKind;
-  }
-
-  public Optional<String> resourceId() {
-    return Optional.ofNullable(resourceId);
-  }
-
-  public Optional<String> relation() {
-    return Optional.ofNullable(relation);
-  }
-
-  public Optional<SubjectFilter> subjectFilter() {
-    return Optional.ofNullable(subjectFilter);
-  }
+  String resourceKind();
 
-  public static class SubjectFilter {
+  Optional<String> resourceId();
 
-    private final String subjectKind;
+  Optional<String> relation();
 
-    /** optional */
-    private final String subjectId;
+  Optional<SubjectFilter> subjectFilter();
 
-    /** optional */
-    private final String relation;
+  interface SubjectFilter {
 
-    private SubjectFilter(Builder builder) {
-      subjectKind = builder.subjectKind;
-      subjectId = builder.subjectId;
-      relation = builder.relation;
+    static Builder newBuilder() {
+      return new RelationshipFilterImpl.SubjectFilterImpl.Builder();
     }
 
-    public static Builder newBuilder() {
-      return new Builder();
-    }
-
-    public String subjectKind() {
-      return subjectKind;
-    }
+    String subjectKind();
 
-    public Optional<String> subjectId() {
-      return Optional.ofNullable(subjectId);
-    }
-
-    public Optional<String> relation() {
-      return Optional.ofNullable(relation);
-    }
+    Optional<String> subjectId();
 
-    public static final class Builder {
-      private String subjectKind;
-      private String subjectId;
-      private String relation;
+    Optional<String> relation();
 
-      private Builder() {}
+    interface Builder {
 
-      public Builder subjectKind(String val) {
-        subjectKind = val;
-        return this;
-      }
+      Builder subjectKind(String val);
 
-      public Builder subjectId(String val) {
-        subjectId = val;
-        return this;
-      }
+      Builder subjectId(String val);
 
-      public Builder relation(String val) {
-        relation = val;
-        return this;
-      }
+      Builder relation(String val);
 
-      public SubjectFilter build() {
-        return new SubjectFilter(this);
-      }
+      SubjectFilter build();
     }
   }
 
-  public static final class Builder {
-    private String resourceKind;
-    private String resourceId;
-    private String relation;
-    private SubjectFilter subjectFilter;
+  interface Builder {
 
-    private Builder() {}
+    Builder resourceKind(String val);
 
-    public Builder resourceKind(String val) {
-      resourceKind = val;
-      return this;
-    }
-
-    public Builder resourceId(String val) {
-      resourceId = val;
-      return this;
-    }
+    Builder resourceId(String val);
 
-    public Builder relation(String val) {
-      relation = val;
-      return this;
-    }
+    Builder relation(String val);
 
-    public Builder subjectFilter(SubjectFilter val) {
-      subjectFilter = val;
-      return this;
-    }
+    Builder subjectFilter(SubjectFilter val);
 
-    public RelationshipFilter build() {
-      return new RelationshipFilter(this);
-    }
+    RelationshipFilter build();
   }
 }
diff --git a/api/src/main/java/com/oviva/spicegen/api/UpdateRelationship.java b/api/src/main/java/com/oviva/spicegen/api/UpdateRelationship.java
index dee938b..cc71cfe 100644
--- a/api/src/main/java/com/oviva/spicegen/api/UpdateRelationship.java
+++ b/api/src/main/java/com/oviva/spicegen/api/UpdateRelationship.java
@@ -1,81 +1,28 @@
 package com.oviva.spicegen.api;
 
-import java.util.Objects;
+import com.oviva.spicegen.api.internal.UpdateRelationshipImpl;
 
-public final class UpdateRelationship {
-  private final ObjectRef resource;
+public interface UpdateRelationship {
 
-  private final String relation;
-
-  private final SubjectRef subject;
-
-  private final Operation operation;
-
-  private UpdateRelationship(
-      ObjectRef resource, String relation, SubjectRef subject, Operation operation) {
-    this.resource = resource;
-    this.relation = relation;
-    this.subject = subject;
-    this.operation = operation;
-  }
-
-  public static UpdateRelationship ofUpdate(
-      ObjectRef resource, String relation, ObjectRef subject) {
-    return new UpdateRelationship(
+  static UpdateRelationship ofUpdate(ObjectRef resource, String relation, ObjectRef subject) {
+    return new UpdateRelationshipImpl(
         resource, relation, SubjectRef.ofObject(subject), Operation.UPDATE);
   }
 
-  public static UpdateRelationship ofDelete(
-      ObjectRef resource, String relation, ObjectRef subject) {
-    return new UpdateRelationship(
+  static UpdateRelationship ofDelete(ObjectRef resource, String relation, ObjectRef subject) {
+    return new UpdateRelationshipImpl(
         resource, relation, SubjectRef.ofObject(subject), Operation.DELETE);
   }
 
-  public SubjectRef subject() {
-    return subject;
-  }
+  SubjectRef subject();
 
-  public ObjectRef resource() {
-    return resource;
-  }
+  ObjectRef resource();
 
-  public String relation() {
-    return relation;
-  }
+  String relation();
 
-  public Operation operation() {
-    return operation;
-  }
-
-  @Override
-  public String toString() {
-    var res = resource != null ? resource.toString() : "";
-    var rel = relation != null ? relation : "";
-    var sub = subject != null ? subject.toString() : "";
-    return operation.name() + "(" + res + "#" + rel + "@" + sub + ")";
-  }
-
-  @Override
-  public boolean equals(Object o) {
-    if (this == o) {
-      return true;
-    }
-    if (o == null || getClass() != o.getClass()) {
-      return false;
-    }
-    var that = (UpdateRelationship) o;
-    return Objects.equals(resource, that.resource)
-        && Objects.equals(relation, that.relation)
-        && Objects.equals(subject, that.subject)
-        && operation == that.operation;
-  }
-
-  @Override
-  public int hashCode() {
-    return Objects.hash(resource, relation, subject, operation);
-  }
+  Operation operation();
 
-  public enum Operation {
+  enum Operation {
     UPDATE,
 
     DELETE
diff --git a/api/src/main/java/com/oviva/spicegen/api/UpdateRelationships.java b/api/src/main/java/com/oviva/spicegen/api/UpdateRelationships.java
index c189976..3012535 100644
--- a/api/src/main/java/com/oviva/spicegen/api/UpdateRelationships.java
+++ b/api/src/main/java/com/oviva/spicegen/api/UpdateRelationships.java
@@ -1,62 +1,27 @@
 package com.oviva.spicegen.api;
 
-import java.util.ArrayList;
+import com.oviva.spicegen.api.internal.UpdateRelationshipsImpl;
 import java.util.List;
 
-public final class UpdateRelationships {
+public interface UpdateRelationships {
 
-  private final List<Precondition> preconditions;
-  private final List<UpdateRelationship> updates;
-
-  public static UpdateRelationshipsBuilder newBuilder() {
-    return new UpdateRelationshipsBuilder();
-  }
-
-  private UpdateRelationships(List<UpdateRelationship> updates, List<Precondition> preconditions) {
-    this.updates = List.copyOf(updates);
-    this.preconditions = List.copyOf(preconditions);
-  }
-
-  public List<UpdateRelationship> updates() {
-    return updates;
-  }
-
-  public List<Precondition> preconditions() {
-    return preconditions;
+  static Builder newBuilder() {
+    return new UpdateRelationshipsImpl.Builder();
   }
 
-  public static final class UpdateRelationshipsBuilder {
-    private List<Precondition> preconditions = new ArrayList<>();
-    private List<UpdateRelationship> updates = new ArrayList<>();
-
-    private UpdateRelationshipsBuilder() {}
+  List<UpdateRelationship> updates();
 
-    public static UpdateRelationshipsBuilder newBuilder() {
-      return new UpdateRelationshipsBuilder();
-    }
+  List<Precondition> preconditions();
 
-    public UpdateRelationshipsBuilder preconditions(List<Precondition> preconditions) {
-      this.preconditions = preconditions;
-      return this;
-    }
+  interface Builder {
+    Builder preconditions(List<Precondition> preconditions);
 
-    public UpdateRelationshipsBuilder precondition(Precondition precondition) {
-      this.preconditions.add(precondition);
-      return this;
-    }
+    Builder precondition(Precondition precondition);
 
-    public UpdateRelationshipsBuilder updates(List<UpdateRelationship> updates) {
-      this.updates = updates;
-      return this;
-    }
+    Builder updates(List<UpdateRelationship> updates);
 
-    public UpdateRelationshipsBuilder update(UpdateRelationship updates) {
-      this.updates.add(updates);
-      return this;
-    }
+    Builder update(UpdateRelationship updates);
 
-    public UpdateRelationships build() {
-      return new UpdateRelationships(updates, preconditions);
-    }
+    UpdateRelationships build();
   }
 }
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/CheckPermissionImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/CheckPermissionImpl.java
new file mode 100644
index 0000000..e5d92d4
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/CheckPermissionImpl.java
@@ -0,0 +1,71 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.CheckPermission;
+import com.oviva.spicegen.api.Consistency;
+import com.oviva.spicegen.api.ObjectRef;
+import com.oviva.spicegen.api.SubjectRef;
+
+public record CheckPermissionImpl(
+    ObjectRef resource, String permission, SubjectRef subject, Consistency consistency)
+    implements CheckPermission {
+
+  private CheckPermissionImpl(Builder builder) {
+    this(builder.resource, builder.permission, builder.subject, builder.consistency);
+  }
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  public ObjectRef resource() {
+    return resource;
+  }
+
+  public String permission() {
+    return permission;
+  }
+
+  public SubjectRef subject() {
+    return subject;
+  }
+
+  public Consistency consistency() {
+    return consistency;
+  }
+
+  public static final class Builder implements CheckPermission.Builder {
+    private ObjectRef resource;
+    private String permission;
+    private SubjectRef subject;
+    private Consistency consistency = Consistency.fullyConsistent();
+
+    @Override
+    public Builder resource(ObjectRef resource) {
+      this.resource = resource;
+      return this;
+    }
+
+    @Override
+    public Builder permission(String permission) {
+      this.permission = permission;
+      return this;
+    }
+
+    @Override
+    public Builder subject(SubjectRef subject) {
+      this.subject = subject;
+      return this;
+    }
+
+    @Override
+    public Builder consistency(Consistency consistency) {
+      this.consistency = consistency;
+      return this;
+    }
+
+    @Override
+    public CheckPermission build() {
+      return new CheckPermissionImpl(this);
+    }
+  }
+}
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/ConsistencyImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/ConsistencyImpl.java
new file mode 100644
index 0000000..3330dd8
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/ConsistencyImpl.java
@@ -0,0 +1,14 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.Consistency;
+
+public record ConsistencyImpl(Consistency.Requirement requirement, String consistencyToken)
+    implements Consistency {
+
+  private static final ConsistencyImpl FULLY_CONSISTENT =
+      new ConsistencyImpl(Consistency.Requirement.FULLY_CONSISTENT, null);
+
+  public static ConsistencyImpl fullyConsistent() {
+    return FULLY_CONSISTENT;
+  }
+}
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/PreconditionImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/PreconditionImpl.java
new file mode 100644
index 0000000..fa045db
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/PreconditionImpl.java
@@ -0,0 +1,37 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.Precondition;
+import com.oviva.spicegen.api.RelationshipFilter;
+
+public record PreconditionImpl(Precondition.Condition condition, RelationshipFilter filter)
+    implements Precondition {
+
+  private PreconditionImpl(Builder builder) {
+    this(builder.condition, builder.filter);
+  }
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  public static final class Builder implements Precondition.Builder {
+    private Precondition.Condition condition;
+    private RelationshipFilter filter;
+
+    @Override
+    public Builder condition(Precondition.Condition val) {
+      condition = val;
+      return this;
+    }
+
+    @Override
+    public Builder filter(RelationshipFilter val) {
+      filter = val;
+      return this;
+    }
+
+    public PreconditionImpl build() {
+      return new PreconditionImpl(this);
+    }
+  }
+}
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/RelationshipFilterImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/RelationshipFilterImpl.java
new file mode 100644
index 0000000..9bc5323
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/RelationshipFilterImpl.java
@@ -0,0 +1,100 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.RelationshipFilter;
+import java.util.Optional;
+
+public record RelationshipFilterImpl(
+    String resourceKind,
+    Optional<String> resourceId,
+    Optional<String> relation,
+    Optional<RelationshipFilter.SubjectFilter> subjectFilter)
+    implements RelationshipFilter {
+
+  private RelationshipFilterImpl(Builder builder) {
+    this(
+        builder.resourceKind,
+        Optional.ofNullable(builder.resourceId),
+        Optional.ofNullable(builder.relation),
+        Optional.ofNullable(builder.subjectFilter));
+  }
+
+  public String resourceKind() {
+    return resourceKind;
+  }
+
+  public record SubjectFilterImpl(
+      String subjectKind, Optional<String> subjectId, Optional<String> relation)
+      implements SubjectFilter {
+
+    private SubjectFilterImpl(Builder builder) {
+      this(
+          builder.subjectKind,
+          Optional.ofNullable(builder.subjectId),
+          Optional.ofNullable(builder.relation));
+    }
+
+    public String subjectKind() {
+      return subjectKind;
+    }
+
+    public static final class Builder implements SubjectFilter.Builder {
+      private String subjectKind;
+      private String subjectId;
+      private String relation;
+
+      public Builder subjectKind(String val) {
+        subjectKind = val;
+        return this;
+      }
+
+      public Builder subjectId(String val) {
+        subjectId = val;
+        return this;
+      }
+
+      public Builder relation(String val) {
+        relation = val;
+        return this;
+      }
+
+      public SubjectFilterImpl build() {
+        return new SubjectFilterImpl(this);
+      }
+    }
+  }
+
+  public static final class Builder implements RelationshipFilter.Builder {
+    private String resourceKind;
+    private String resourceId;
+    private String relation;
+    private SubjectFilter subjectFilter;
+
+    @Override
+    public Builder resourceKind(String val) {
+      resourceKind = val;
+      return this;
+    }
+
+    @Override
+    public Builder resourceId(String val) {
+      resourceId = val;
+      return this;
+    }
+
+    @Override
+    public Builder relation(String val) {
+      relation = val;
+      return this;
+    }
+
+    @Override
+    public Builder subjectFilter(SubjectFilter val) {
+      this.subjectFilter = val;
+      return this;
+    }
+
+    public RelationshipFilterImpl build() {
+      return new RelationshipFilterImpl(this);
+    }
+  }
+}
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipImpl.java
new file mode 100644
index 0000000..1daf5bb
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipImpl.java
@@ -0,0 +1,17 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.ObjectRef;
+import com.oviva.spicegen.api.SubjectRef;
+import com.oviva.spicegen.api.UpdateRelationship;
+
+public record UpdateRelationshipImpl(
+    ObjectRef resource, String relation, SubjectRef subject, Operation operation)
+    implements UpdateRelationship {
+  @Override
+  public String toString() {
+    var res = resource != null ? resource.toString() : "";
+    var rel = relation != null ? relation : "";
+    var sub = subject != null ? subject.toString() : "";
+    return operation.name() + "(" + res + "#" + rel + "@" + sub + ")";
+  }
+}
diff --git a/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipsImpl.java b/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipsImpl.java
new file mode 100644
index 0000000..0856a99
--- /dev/null
+++ b/api/src/main/java/com/oviva/spicegen/api/internal/UpdateRelationshipsImpl.java
@@ -0,0 +1,58 @@
+package com.oviva.spicegen.api.internal;
+
+import com.oviva.spicegen.api.Precondition;
+import com.oviva.spicegen.api.UpdateRelationship;
+import com.oviva.spicegen.api.UpdateRelationships;
+import java.util.ArrayList;
+import java.util.List;
+
+public record UpdateRelationshipsImpl(
+    List<Precondition> preconditions, List<UpdateRelationship> updates)
+    implements UpdateRelationships {
+
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  public List<UpdateRelationship> updates() {
+    return updates;
+  }
+
+  public List<Precondition> preconditions() {
+    return preconditions;
+  }
+
+  public static final class Builder implements UpdateRelationships.Builder {
+    private List<Precondition> preconditions = new ArrayList<>();
+    private List<UpdateRelationship> updates = new ArrayList<>();
+
+    @Override
+    public UpdateRelationships.Builder preconditions(List<Precondition> preconditions) {
+      this.preconditions = preconditions;
+      return this;
+    }
+
+    @Override
+    public UpdateRelationships.Builder precondition(Precondition precondition) {
+      this.preconditions.add(precondition);
+      return this;
+    }
+
+    @Override
+    public UpdateRelationships.Builder updates(List<UpdateRelationship> updates) {
+      this.updates = updates;
+      return this;
+    }
+
+    @Override
+    public UpdateRelationships.Builder update(UpdateRelationship updates) {
+      this.updates.add(updates);
+      return this;
+    }
+
+    @Override
+    public UpdateRelationships build() {
+      return new UpdateRelationshipsImpl(preconditions, updates);
+    }
+  }
+}
diff --git a/api/src/test/java/com/oviva/spicegen/api/UpdateRelationshipsTest.java b/api/src/test/java/com/oviva/spicegen/api/UpdateRelationshipsTest.java
index 4633521..7346046 100644
--- a/api/src/test/java/com/oviva/spicegen/api/UpdateRelationshipsTest.java
+++ b/api/src/test/java/com/oviva/spicegen/api/UpdateRelationshipsTest.java
@@ -34,10 +34,7 @@ public void test_updateRelationshipsBuilder() {
     var preconditions = getPreconditionList();
 
     var updateRelationships =
-        UpdateRelationships.UpdateRelationshipsBuilder.newBuilder()
-            .updates(updates)
-            .preconditions(preconditions)
-            .build();
+        UpdateRelationships.newBuilder().updates(updates).preconditions(preconditions).build();
 
     assertEquals(updateRelationships.updates(), updates);
     assertEquals(updateRelationships.preconditions(), preconditions);
@@ -65,7 +62,7 @@ public void test_updateRelationshipsBuilder_withAddOperations() {
     var updateRelationship = UpdateRelationship.ofUpdate(resource, ADMINISTRATOR, subject);
 
     var updateRelationships =
-        UpdateRelationships.UpdateRelationshipsBuilder.newBuilder()
+        UpdateRelationships.newBuilder()
             .precondition(precondition)
             .update(updateRelationship)
             .build();
diff --git a/spicedb-binding/pom.xml b/spicedb-binding/pom.xml
index 6ba783a..2d04dcf 100644
--- a/spicedb-binding/pom.xml
+++ b/spicedb-binding/pom.xml
@@ -64,6 +64,11 @@
             <artifactId>testcontainers</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.testcontainers</groupId>
+            <artifactId>postgresql</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.testcontainers</groupId>
             <artifactId>junit-jupiter</artifactId>
diff --git a/spicedb-binding/src/main/docker/compose.dev.yaml b/spicedb-binding/src/main/docker/compose.dev.yaml
deleted file mode 100644
index 511ba25..0000000
--- a/spicedb-binding/src/main/docker/compose.dev.yaml
+++ /dev/null
@@ -1,43 +0,0 @@
-version: "3.9"
-services:
-  spicedb:
-    image: quay.io/authzed/spicedb
-    ports:
-      - "127.0.0.1::8080"
-      - "127.0.0.1::50051"
-      - "127.0.0.1::9090"
-    command:
-      - 'serve'
-      - '--grpc-preshared-key=t0ken'
-      - '--datastore-engine=postgres'
-      - '--datastore-conn-uri=postgres://spicedb-pg:5432/spicedb?sslmode=disable&user=postgres&password=root'
-    depends_on:
-      spicedb-pg:
-        condition: service_healthy
-      spicedb-migrator:
-        condition: service_completed_successfully
-  spicedb-migrator:
-    image: quay.io/authzed/spicedb
-    command:
-      - 'migrate'
-      - 'head'
-      - '--datastore-engine'
-      - 'postgres'
-      - '--datastore-conn-uri'
-      - 'postgres://spicedb-pg:5432/spicedb?sslmode=disable&user=postgres&password=root'
-    depends_on:
-      spicedb-pg:
-        condition: service_healthy
-  spicedb-pg:
-    image: postgres:14
-    ports:
-      - "127.0.0.1::5432"
-    environment:
-      POSTGRES_DB: 'spicedb'
-      POSTGRES_PASSWORD: 'root'
-    healthcheck:
-      test: "psql 'postgres://spicedb-pg:5432/spicedb?sslmode=disable&user=postgres&password=root' --quiet --output=/dev/null -c 'SELECT 1;'"
-      interval: 1s
-      timeout: 1s
-      retries: 3
-      start_period: 10s
\ No newline at end of file
diff --git a/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/SpiceDbPermissionServiceBuilderTest.java b/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/SpiceDbPermissionServiceBuilderTest.java
index 15fb96d..7b73709 100644
--- a/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/SpiceDbPermissionServiceBuilderTest.java
+++ b/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/SpiceDbPermissionServiceBuilderTest.java
@@ -1,6 +1,6 @@
 package com.oviva.spicegen.spicedbbinding;
 
-import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 
 import com.authzed.api.v1.PermissionsServiceGrpc;
 import com.authzed.grpcutil.BearerToken;
@@ -27,6 +27,6 @@ public void test_spiceDbPermissionServiceBuilder() {
             .permissionsBlockingStub(permissionsService)
             .build();
 
-    assertTrue(svc instanceof PermissionService);
+    assertInstanceOf(PermissionService.class, svc);
   }
 }
diff --git a/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/internal/SpiceDbContractTestContextProvider.java b/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/internal/SpiceDbContractTestContextProvider.java
index 410dd83..6df6103 100644
--- a/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/internal/SpiceDbContractTestContextProvider.java
+++ b/spicedb-binding/src/test/java/com/oviva/spicegen/spicedbbinding/internal/SpiceDbContractTestContextProvider.java
@@ -6,17 +6,23 @@
 import com.oviva.spicegen.spicedbbinding.test.GenericTypedParameterResolver;
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
-import java.io.File;
+import java.time.Duration;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Stream;
 import org.junit.jupiter.api.extension.*;
-import org.testcontainers.containers.DockerComposeContainer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.testcontainers.containers.GenericContainer;
+import org.testcontainers.containers.Network;
+import org.testcontainers.containers.PostgreSQLContainer;
+import org.testcontainers.containers.startupcheck.OneShotStartupCheckStrategy;
+import org.testcontainers.containers.wait.strategy.LogMessageWaitStrategy;
 import org.testcontainers.utility.DockerImageName;
 
 public class SpiceDbContractTestContextProvider implements TestTemplateInvocationContextProvider {
 
+  private static Logger logger = LoggerFactory.getLogger(SpiceDbContractTestContextProvider.class);
   private static final String TOKEN = "t0ken";
   private static final int GRPC_PORT = 50051;
 
@@ -35,14 +41,10 @@ public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContex
   private TestTemplateInvocationContext inMemorySpiceDB() {
 
     var spicedb =
-        new GenericContainer<>(DockerImageName.parse("quay.io/authzed/spicedb:v1.32.0"))
-            .withCommand("serve", "--grpc-preshared-key", TOKEN)
-            .withExposedPorts(
-                GRPC_PORT, // grpc
-                8080, // dashboard
-                9090 // metrics
-                );
-
+        createSpicedbBaseContainer("serve", "--grpc-preshared-key", TOKEN)
+            .withExposedPorts(GRPC_PORT)
+            .waitingFor(
+                new LogMessageWaitStrategy().withRegEx(".*\"grpc server started serving\".*"));
     spicedb.start();
 
     var host = spicedb.getHost();
@@ -61,22 +63,45 @@ private TestTemplateInvocationContext inMemorySpiceDB() {
 
   private TestTemplateInvocationContext postgresSpiceDB() {
 
-    var spiceDbServiceName = "spicedb_1";
-    var environment =
-        new DockerComposeContainer<>(new File("src/main/docker/compose.dev.yaml"))
-            .withExposedService(spiceDbServiceName, GRPC_PORT);
-
-    environment.start();
+    var net = Network.newNetwork();
+
+    var migrator =
+        createSpicedbBaseContainer(
+                "migrate",
+                "head",
+                "--datastore-engine",
+                "postgres",
+                "--datastore-conn-uri",
+                "postgres://spicedb-pg:5432/spicedb?sslmode=disable&user=postgres&password=root")
+            .withStartupCheckStrategy(
+                new OneShotStartupCheckStrategy().withTimeout(Duration.ofSeconds(5)))
+            .withNetwork(net);
+
+    var spicedb = createPostgeresSpicedbContainer(net);
+
+    var db =
+        new PostgreSQLContainer<>(DockerImageName.parse("postgres").withTag("14"))
+            .withDatabaseName("spicedb")
+            .withPassword("root")
+            .withUsername("postgres")
+            .withNetworkAliases("spicedb-pg")
+            .withNetwork(net);
+
+    db.start();
+    migrator.start();
+    spicedb.start();
 
-    var host = environment.getServiceHost(spiceDbServiceName, GRPC_PORT);
-    var port = environment.getServicePort(spiceDbServiceName, GRPC_PORT);
+    var host = spicedb.getHost();
+    var port = spicedb.getMappedPort(GRPC_PORT);
     var services = createServices(host, port);
     return createContext(
         "postgres backed SpiceDB",
         services,
         () -> {
           quitelyShutdown(services.channel());
-          environment.stop();
+          migrator.stop();
+          spicedb.stop();
+          db.stop();
         });
   }
 
@@ -113,6 +138,29 @@ public List<Extension> getAdditionalExtensions() {
     };
   }
 
+  private GenericContainer<?> createPostgeresSpicedbContainer(Network net) {
+
+    return createSpicedbBaseContainer(
+            "serve",
+            "--grpc-preshared-key=%s".formatted(TOKEN),
+            "--datastore-engine=postgres",
+            "--datastore-conn-uri=postgres://spicedb-pg:5432/spicedb?sslmode=disable&user=postgres&password=root")
+        .waitingFor(new LogMessageWaitStrategy().withRegEx(".*\"grpc server started serving\".*"))
+        .withExposedPorts(
+            GRPC_PORT, // grpc
+            8080, // dashboard
+            9090 // metrics
+            )
+        .withNetwork(net);
+  }
+
+  private GenericContainer<?> createSpicedbBaseContainer(String... args) {
+
+    return new GenericContainer<>(DockerImageName.parse("quay.io/authzed/spicedb:v1.32.0"))
+        .withCommand(args)
+        .withLogConsumer(f -> logger.info("spicedb {}: {}", args[0], f.getUtf8String()));
+  }
+
   public TestServices createServices(String host, int port) {
 
     var channel = ManagedChannelBuilder.forAddress(host, port).usePlaintext().build();