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HTTP 103 Early Hints Builder

Build RFC 8297 103 Early Hints responses with Link: rel=preload and rel=preconnect headers. Tells browsers to start fetching critical assets before your backend finishes rendering the final response — a clean alternative to HTTP/2 Server Push.

Hints

RelURLas / typecrossorigin

103 Early Hints response

Final 200 response headers (mirror the hints)

Timing illustration

Server snippets

Node.js (Express + writeEarlyHints)

    
Nginx (ngx_http_v2 + add_header)

    
Cloudflare Workers

  







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