diff --git a/packages/iios-service/src/messaging/message.service.ts b/packages/iios-service/src/messaging/message.service.ts
index beaa0d1..0df9d97 100644
--- a/packages/iios-service/src/messaging/message.service.ts
+++ b/packages/iios-service/src/messaging/message.service.ts
@@ -506,7 +506,7 @@ export class MessageService {
       id: interaction.id,
       threadId,
       senderActorId: interaction.actorId ?? '',
-      senderName: interaction.actor?.sourceHandle?.externalId ?? interaction.actor?.displayName ?? 'unknown',
+      senderName: interaction.actor?.displayName ?? interaction.actor?.sourceHandle?.externalId ?? 'unknown',
       content: text?.bodyText ?? '',
       contentRef: file?.contentRef ?? undefined,
       parentInteractionId: interaction.parentInteractionId ?? undefined,
diff --git a/packages/iios-service/src/platform/session.verifier.ts b/packages/iios-service/src/platform/session.verifier.ts
index fa7e28d..63a38f3 100644
--- a/packages/iios-service/src/platform/session.verifier.ts
+++ b/packages/iios-service/src/platform/session.verifier.ts
@@ -1,30 +1,113 @@
-import { Injectable, UnauthorizedException } from '@nestjs/common';
+import { createPublicKey } from 'node:crypto';
+import { Injectable, OnModuleInit, UnauthorizedException } from '@nestjs/common';
 import jwt from 'jsonwebtoken';
 import type { MessagePrincipal } from '../messaging/message.service';
 
 /**
- * The real `session` port for P2: verifies a host app's HS256 token (reuses the
- * support-service AppTokenVerifier pattern). Per-app secrets come from the
- * APP_SECRETS env (JSON map keyed by appId). Expected claims: { sub, name?,
- * appId, orgId?, tenantId? }.
+ * The `session` port. Two verification modes, chosen by env:
+ *
+ *  1. Supabase (real IdP) — set `SUPABASE_URL`. User access tokens (SATs) are
+ *     ES256, signed by the project's rotating key; we verify them against the
+ *     project's public JWKS (no shared secret). This is the production identity
+ *     plane's front door (a Session Broker would later exchange the SAT for a
+ *     scoped PAT — until then we trust the SAT directly and scope from config).
+ *
+ *  2. App token (dev / HS256) — the legacy path. Per-app secrets from `APP_SECRETS`
+ *     (JSON keyed by appId); claims { sub, name?, appId, orgId?, tenantId? }.
+ *
+ * Same `MessagePrincipal` out either way, so nothing downstream changes.
  */
 @Injectable()
-export class SessionVerifier {
-  private readonly secrets: Record<string, string>;
+export class SessionVerifier implements OnModuleInit {
+  private readonly appSecrets: Record<string, string>;
+  private readonly supabaseUrl?: string; // base origin, no trailing slash / path
+  private readonly appId = process.env.SUPABASE_APP_ID?.trim() || 'portal-demo';
+  private readonly orgId: string;
+  private kidToPem = new Map<string, string>();
 
   constructor() {
     try {
-      this.secrets = JSON.parse(process.env.APP_SECRETS ?? '{}');
+      this.appSecrets = JSON.parse(process.env.APP_SECRETS ?? '{}');
     } catch {
-      this.secrets = {};
+      this.appSecrets = {};
+    }
+    // Accept the project URL in any shape they paste (.../rest/v1, .../auth/v1, trailing slash).
+    const raw = process.env.SUPABASE_URL?.trim().replace(/\/+$/, '').replace(/\/(rest|auth)\/v1$/, '');
+    this.supabaseUrl = raw || undefined;
+    this.orgId = process.env.SUPABASE_ORG_ID?.trim() || `org_${this.appId}`;
+  }
+
+  async onModuleInit(): Promise<void> {
+    if (this.supabaseUrl) await this.refreshJwks();
+  }
+
+  /** Fetch the project JWKS and cache each key as a PEM so verify() can stay synchronous. */
+  private async refreshJwks(): Promise<void> {
+    try {
+      const res = await fetch(`${this.supabaseUrl}/auth/v1/.well-known/jwks.json`);
+      if (!res.ok) return;
+      const { keys } = (await res.json()) as { keys: Array<Record<string, unknown>> };
+      const next = new Map<string, string>();
+      for (const jwk of keys ?? []) {
+        const kid = jwk.kid as string | undefined;
+        if (!kid) continue;
+        try {
+          next.set(kid, createPublicKey({ key: jwk as never, format: 'jwk' }).export({ type: 'spki', format: 'pem' }) as string);
+        } catch {
+          /* skip a key we can't import */
+        }
+      }
+      if (next.size) this.kidToPem = next;
+    } catch {
+      /* keep whatever keys we already have */
     }
   }
 
   verify(token: string): MessagePrincipal {
-    const decoded = jwt.decode(token) as jwt.JwtPayload | null;
-    const appId = decoded?.appId ? String(decoded.appId) : undefined;
+    const decoded = jwt.decode(token, { complete: true }) as { header?: { alg?: string; kid?: string }; payload?: jwt.JwtPayload } | null;
+    if (!decoded?.payload) throw new UnauthorizedException('invalid token');
+    if (this.supabaseUrl && decoded.header?.alg === 'ES256') {
+      return this.verifySupabase(token, decoded.header.kid);
+    }
+    return this.verifyAppToken(token, decoded.payload);
+  }
+
+  /** Verify a Supabase SAT (ES256) against the cached JWKS public key. */
+  private verifySupabase(token: string, kid?: string): MessagePrincipal {
+    const pem = kid ? this.kidToPem.get(kid) : undefined;
+    if (!pem) {
+      void this.refreshJwks(); // key rotated or not loaded yet — pull fresh for next time
+      throw new UnauthorizedException('unknown signing key — retry');
+    }
+    let payload: jwt.JwtPayload;
+    try {
+      payload = jwt.verify(token, pem, {
+        algorithms: ['ES256'],
+        issuer: `${this.supabaseUrl}/auth/v1`,
+        audience: 'authenticated',
+      }) as jwt.JwtPayload;
+    } catch {
+      throw new UnauthorizedException('invalid supabase token');
+    }
+    const email = payload.email ? String(payload.email).toLowerCase() : undefined;
+    const meta = (payload.user_metadata ?? {}) as { full_name?: string; name?: string };
+    // userId = email (unique + stable + human-readable → keeps mentions/directory working).
+    // The canonical UUID (sub) is what RealMDM would resolve later.
+    const userId = email ?? String(payload.sub);
+    return {
+      userId,
+      appId: this.appId,
+      orgId: this.orgId,
+      tenantId: undefined,
+      displayName: meta.full_name ?? meta.name ?? email ?? userId,
+    };
+  }
+
+  /** Legacy per-app HS256 token (dev IdP / host apps). */
+  private verifyAppToken(token: string, decodedPayload: jwt.JwtPayload): MessagePrincipal {
+    const appId = decodedPayload.appId ? String(decodedPayload.appId) : undefined;
     if (!appId) throw new UnauthorizedException('missing appId claim');
-    const secret = this.secrets[appId];
+    const secret = this.appSecrets[appId];
     if (!secret) throw new UnauthorizedException(`unknown app: ${appId}`);
 
     let payload: jwt.JwtPayload;