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auth0-dpop

★ 37

by auth0 · part of auth0/agent-skills

Use when adding DPoP (Demonstrating Proof-of-Possession) token binding to protect API calls with device-bound, sender-constrained access tokens that cannot be replayed if stolen. Also use when a user says "bind tokens to the client", "prevent token theft", or "sender-constrained tokens".

🧩 One of 7 skills in the auth0/agent-skills package — works on its own, and pairs well with its siblings.

This is the playbook your agent receives when the skill activates — you don't need to read it to use the skill, but it's here to audit before installing.

Auth0 DPoP Guide

Bind access tokens to the client's cryptographic key so stolen tokens cannot be replayed.

Overview

What is DPoP?

DPoP (Demonstrating Proof-of-Possession) is an OAuth 2.0 mechanism defined in RFC 9449 that cryptographically binds access tokens to a client-held key pair. Each API request includes a short-lived signed JWT (the DPoP proof) that proves the sender holds the private key — a stolen token alone cannot be replayed by an attacker.

When to Use This Skill

  • Protecting high-value API calls against token theft and replay attacks
  • Meeting security or compliance requirements that mandate sender-constrained tokens
  • Any SPA or Vanilla JS app calling a protected Auth0 API with elevated security needs

When NOT to Use This Skill

  • SSR / server-side environments — DPoP relies on a private key held in the browser; it cannot be safely used server-side (Next.js, Nuxt, etc.)
  • APIs that don't support DPoP — the resource server must be configured to accept DPoP token dialect; Bearer-only APIs will reject DPoP proofs
  • Flows requiring token sharing — DPoP tokens are bound to a single key pair and cannot be forwarded to or reused by another client

Requirements

  • Auth0 tenant with DPoP-capable authorization server
  • API resource server with DPoP token dialect enabled
  • A browser SPA using one of: @auth0/auth0-vue, @auth0/auth0-react, @auth0/auth0-angular, or @auth0/auth0-spa-js
  • HTTPS in production (required by Auth0 for DPoP)

Key Concepts

ConceptDescription
DPoP ProofA short-lived signed JWT attached to each request proving key possession
DPoP NonceA server-issued value that must be included in the proof to prevent replay
useDpop: trueSDK option that enables automatic DPoP proof generation
createFetcher()SDK helper that returns a fetch-compatible function handling proofs automatically
UseDpopNonceErrorError thrown when the server rotates its nonce mid-flight; retry with the new nonce

Step 1: Enable DPoP on Your API

Via Auth0 Dashboard

  1. Go to Applications → APIs
  2. Select the API your SPA calls
  3. Under the Settings tab, confirm the API identifier matches your audience
  4. No additional toggle is needed in the dashboard — DPoP is enabled per-request by the client when the API resource server is configured to accept DPoP tokens

Via Auth0 CLI

# Inspect current resource server settings
auth0 api get "resource-servers" | jq '.[] | select(.identifier == "https://your-api-identifier")'

# Enable DPoP token dialect on the API
auth0 api patch "resource-servers/{API_ID}" \
  --data '{"token_dialect": "access_token_authz"}'

Replace {API_ID} with the ID returned from the GET call above.

Step 2: Configure Your Application

Common pattern across all frameworks

  1. Add useDpop: true to your Auth0 client/provider configuration alongside your audience
  2. Use createFetcher() instead of attaching tokens manually — the SDK handles proof generation, nonce management, and header injection for you
  3. Handle UseDpopNonceError in cases where the server rotates its nonce

Environment variables

Ensure your .env includes the API audience:

# Vite
VITE_AUTH0_DOMAIN=your-tenant.auth0.com
VITE_AUTH0_CLIENT_ID=your-client-id
VITE_AUTH0_AUDIENCE=https://your-api-identifier

Additional Resources

Framework Examples

Complete implementation examples for all supported frameworks:

  • Vue.js
  • React
  • Angular
  • auth0-spa-js (Vanilla JS)

Integration Guide

Error handling and troubleshooting:

  • UseDpopNonceError — nonce rotation handling
  • Common issues
  • auth0-vue - Vue.js Auth0 integration
  • auth0-react - React Auth0 integration
  • auth0-angular - Angular Auth0 integration
  • auth0-spa-js - Vanilla JS / framework-agnostic SPA integration
  • auth0-mfa - Multi-factor authentication

References