JWT Decoder API
Let your coding agent decode and inspect JWTs while you debug auth, OAuth, or session bugs without leaving the chat.
Overview
JWT Decoder is a MCP server for the Ship phase that decodes JWT tokens so agents can inspect headers, payloads, claims, and expiry over a remote SSE endpoint.
What is this MCP server?
- Decodes JWT header, payload, claims, and expiration in one call
- Remote MCP over SSE at jwt-decoder.api.klymax402.com
- x402 micropayment billing on the hosted API
- Useful for OAuth, session cookies, and API gateway token debugging
- No local crypto libs required—agent calls the MCP remote
- Catalog version 1.1.0
- Transport: remote MCP SSE
- Billing model: x402 micropayment
What problem does it solve?
Auth bugs stall releases when you cannot quickly see what is inside a token your app or IdP issued.
Who is it for?
Indie builders debugging login, API auth, or webhook bearer tokens during ship and security review.
Skip if: Teams that need offline-only token handling, full cryptographic signature verification as a turnkey service, or zero network egress.
What do I get? / Deliverables
Your agent returns structured JWT parts and expiry so you can fix claim mismatches, clock skew, and wrong audiences faster.
- Decoded JWT header and payload for agent-side reasoning
- Visible standard claims and expiration timestamp
- Faster auth defect triage without manual decoder sites
Recommended MCP Servers
Journey fit
How it compares
Remote JWT inspection MCP, not a local OpenID or full auth stack skill.
Common Questions / FAQ
Who is JWT Decoder for?
Solo and small-team builders using AI coding agents who need fast, readable JWT breakdowns while fixing auth in APIs and web apps.
When should I use JWT Decoder?
Use it during ship and security work when a token looks wrong—wrong role, sudden 401s, or confusing exp—and you want the agent to decode it in context.
How do I add JWT Decoder to my agent?
Add the remote MCP server URL https://jwt-decoder.api.klymax402.com/mcp (type sse) in Claude Code, Cursor, or another MCP client, then account for x402 micropayment on the hosted API.