HTTP
425 Too Early
The server is unwilling to risk processing a request that might be replayed. Used with TLS 1.3 early data (0-RTT).
When You See This Code
When a server rejects a request sent as TLS 1.3 early data due to replay risk.
How to Fix
Retry the request after the TLS handshake completes.
Specification
View RFC / Specification →Guides
Understanding HTTP Status Codes: A Complete Guide
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HTTP Redirects: 301 vs 302 vs 307 vs 308
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HTTP Caching: Cache-Control, ETags, and 304 Responses
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Debugging 502 Bad Gateway Errors
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Debugging CORS Errors: A Developer's Guide
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Debugging Timeout Errors: 408 and 504
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401 Unauthorized vs 403 Forbidden: When to Use Each
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Essential HTTP Security Headers
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Complete Guide to HTTP Methods: GET, POST, PUT, PATCH, DELETE
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Essential HTTP Headers Every Developer Should Know
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HTTP/2 vs HTTP/3: What Changed and Why
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How to Implement and Handle Rate Limiting (429)
API Design
API Versioning Strategies: URL, Header, and Query Param
API Design
Designing Consistent API Error Responses
API Design
Debugging 503 Service Unavailable Errors in Production
Debugging & Troubleshooting
TLS/SSL Certificate Troubleshooting Guide
Debugging & Troubleshooting
OAuth 2.0 Flows Explained: Authorization Code, Client Credentials, PKCE
Security & Authentication
JSON Web Tokens: Structure, Signing, and Common Pitfalls
Security & Authentication
API Keys vs OAuth vs JWT: Choosing the Right Auth Method
Security & Authentication