{"uid":"cap_ap0qVBtLDok3NYyIDiecK","slug":"fastapi-online-jwt-decode-25a66e67","name":"fastapi.online JWT Decode","description":"Chat, embeddings, OCR, speech-to-text, image editing, image understanding (captioning/Q&A), text-to-speech, translation, writing tools, classification tools, developer tools, local utilities, format/checksum validators, encoding & crypto utilities, date/time calculators, geo/coordinate math, math & finance calculators, novelty tools, and business/social writing generators — 179 endpoints in all, across multiple specialized self-hosted models. Pay per call with crypto — no signup — or get an API key.","url":"https://api.fastapi.online/jwt-decode","method":"POST","headers":{},"bodySchema":{"type":"object","properties":{"token":{"type":"string","maxLength":8000,"minLength":1}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.0005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.0005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.0005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_oslN0Gpc5TBXP8RKU6dqw","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.0005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Decodes a JWT token and returns its header, payload, and signature components without verification","exampleAgentPrompt":"Can you decode this JWT token for me and show me what's in the payload: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c","exampleUseCases":[{"title":"Inspect auth token claims","prompt":"I have this JWT from our auth system and I need to see what claims are inside it — can you decode it for me? Here's the token: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiJhYmMxMjMiLCJyb2xlIjoiYWRtaW4iLCJleHAiOjE3MDA1MDAwMDB9.signature"},{"title":"Debug expired token payload","prompt":"I'm getting auth errors in my app and I want to check if this JWT is expired — can you decode it and show me the exp and iat fields? Token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpYXQiOjE2MDAwMDAwMDAsImV4cCI6MTYwMDAwMTAwMH0.abc123"},{"title":"Audit third-party token structure","prompt":"We received a JWT from a third-party service and I need to understand its structure — what algorithm is it using in the header and what data is in the payload? Here's the token: eyJhbGciOiJFUzI1NiIsInR5cCI6IkpXVCIsImtpZCI6ImtleS0xIn0.eyJzdWIiOiJ1c2VyXzQ1NiIsInNjb3BlcyI6WyJyZWFkIiwid3JpdGUiXX0.signature_here"}],"resultDescription":"Returns the decoded JWT broken into its three components: the header object (containing algorithm and token type), the payload object (containing all claims such as sub, iat, exp, roles, and any custom claims), and the signature string — all without performing cryptographic signature verification.","failureModes":["Malformed or non-JWT string returns a parsing error","Token exceeding 8000 characters is rejected","Empty token string is rejected by input validation","Network or payment failure (402) if USDC payment is not provided","Signature is NOT verified — this endpoint only decodes, does not authenticate"],"whenToPreferThis":"Use this endpoint when you need to quickly inspect or debug the contents of a JWT token without needing cryptographic signature verification. It is ideal for development and debugging workflows where you want to read claims, check expiry, or audit token structure. Prefer this over manual base64 decoding for convenience in agent pipelines.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-14T18:32:53.685Z","isFirstParty":false}