diff --git a/backend/src/auth/models/authenticated-user.models.ts b/backend/src/auth/models/authenticated-user.models.ts
index bc3e29d54e..2c4c64ace4 100644
--- a/backend/src/auth/models/authenticated-user.models.ts
+++ b/backend/src/auth/models/authenticated-user.models.ts
@@ -1,4 +1,4 @@
-import { User } from '@supabase/supabase-js';
+import { User as SupabaseUser } from '@supabase/supabase-js';
 
 export enum UserRole {
   AUTHENTICATED = 'authenticated',
@@ -6,6 +6,24 @@ export enum UserRole {
   ANON = 'anon', // Anonymous
 }
 
+export type User = SupabaseUser;
+
+export interface AnonymousUser extends User {
+  role: UserRole.ANON;
+  is_anonymous: true;
+}
+
 export interface AuthenticatedUser extends User {
-  role: UserRole;
+  role: UserRole.AUTHENTICATED;
+  is_anonymous: false;
+}
+
+export function isAnonymousUser(user: User | null): user is AnonymousUser {
+  return user?.role === UserRole.ANON && user.is_anonymous === true;
+}
+
+export function isAuthenticatedUser(
+  user: User | null
+): user is AuthenticatedUser {
+  return user?.role === UserRole.AUTHENTICATED && user.is_anonymous === false;
 }
diff --git a/backend/src/auth/services/auth.service.ts b/backend/src/auth/services/auth.service.ts
index 6d3050545c..ff14baa62b 100644
--- a/backend/src/auth/services/auth.service.ts
+++ b/backend/src/auth/services/auth.service.ts
@@ -4,6 +4,8 @@ import { and, eq, inArray, sql, SQL, SQLWrapper } from 'drizzle-orm';
 import DatabaseService from '../../common/services/database.service';
 import {
   AuthenticatedUser,
+  isAuthenticatedUser,
+  User,
   UserRole,
 } from '../models/authenticated-user.models';
 import {
@@ -163,7 +165,7 @@ export class AuthService {
    * @param doNotThrow vrai pour ne pas générer une exception
    */
   async verifieAccesRestreintCollectivite(
-    user: AuthenticatedUser,
+    user: User,
     collectiviteId: number,
     doNotThrow?: boolean
   ): Promise<boolean> {
@@ -172,7 +174,7 @@ export class AuthService {
         `Rôle de service détecté, accès autorisé à toutes les collectivités`
       );
       return true;
-    } else if (user.role === UserRole.AUTHENTICATED) {
+    } else if (isAuthenticatedUser(user)) {
       let authorise = false;
       const collectivite = await this.collectiviteService.getCollectivite(
         collectiviteId
diff --git a/backend/src/trpc/trpc.service.ts b/backend/src/trpc/trpc.service.ts
index afb2d2e1c6..6ef8b4eba1 100644
--- a/backend/src/trpc/trpc.service.ts
+++ b/backend/src/trpc/trpc.service.ts
@@ -1,7 +1,10 @@
 import { Injectable } from '@nestjs/common';
 import { initTRPC, TRPCError } from '@trpc/server';
+import {
+  isAnonymousUser,
+  isAuthenticatedUser,
+} from '../auth/models/authenticated-user.models';
 import { Context } from './trpc.router';
-import { AuthenticatedUser } from '../auth/models/authenticated-user.models';
 
 @Injectable()
 export class TrpcService {
@@ -14,9 +17,26 @@ export class TrpcService {
 
   publicProcedure = this.trpc.procedure;
 
+  anonProcedure = this.trpc.procedure.use(
+    this.trpc.middleware(({ next, ctx }) => {
+      const anonUser = ctx.user;
+
+      if (!isAnonymousUser(anonUser)) {
+        throw new TRPCError({
+          code: 'UNAUTHORIZED',
+          message: 'Not anonymous',
+        });
+      }
+
+      return next({ ctx: { user: anonUser } });
+    })
+  );
+
   authedProcedure = this.trpc.procedure.use(
     this.trpc.middleware(({ next, ctx }) => {
-      if (ctx.user === null) {
+      const authUser = ctx.user;
+
+      if (!isAuthenticatedUser(authUser)) {
         throw new TRPCError({
           code: 'UNAUTHORIZED',
           message: 'Not authenticated',
@@ -25,7 +45,7 @@ export class TrpcService {
 
       return next({
         ctx: {
-          user: ctx.user as AuthenticatedUser,
+          user: authUser,
         },
       });
     })
diff --git a/doc/adr/0004-trpc.md b/doc/adr/0004-trpc.md
index e071439fcc..9ecbca55ef 100644
--- a/doc/adr/0004-trpc.md
+++ b/doc/adr/0004-trpc.md
@@ -134,7 +134,8 @@ countByStatut: this.trpc.publicProcedure.input(inputSchema).query(({ input }) =>
 /* Dans le router */
 countByStatut: this.trpc.authedProcedure.input(inputSchema).query(({ input, ctx }) => {
   const { collectiviteId, body } = input;
-  return this.service.countByStatut(collectiviteId, body, ctx.user);
+  const authenticatedUser = ctx.user;
+  return this.service.countByStatut(collectiviteId, body, authenticatedUser);
 });
 
 /* Dans le service */
@@ -142,6 +143,17 @@ const uuid = user.id;
 const role = user.role;
 ```
 
+- `anonProcedure` pour les routes avec un token anonyme et récupération du user (anonyme) via le `ctx` de la query.
+
+```typescript
+/* Dans le router */
+countByStatut: this.trpc.anonProcedure.input(inputSchema).query(({ input, ctx }) => {
+  const { collectiviteId, body } = input;
+  const anonymousUser = ctx.user;
+  return this.service.countByStatut(collectiviteId, body, anonymousUser);
+});
+```
+
 ## Améliorations possibles
 
 - Mise en place d'outils facilitant la DX.