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HTTP Priority Header (RFC 9218) Parser / Builder

Network

Build an HTTP Priority request/response-header value from an urgency (0-7) and/or an incremental flag, or parse an existing one, per RFC 9218

The Priority header from RFC 9218 (Extensible Prioritization Scheme for HTTP) lets a client hint how urgently it wants a response and whether it can start using a partial, incremental response, replacing the older HTTP/2 stream-dependency priority model that most servers never fully implemented. This tool builds a header value from an urgency (0 for most urgent down to 7 for least, defaulting to 3) and an incremental flag, or parses an existing value with the same defaults applied to whichever field was left out. It follows the RFC 8941 Structured Field Dictionary syntax the header uses, including the bare-key shorthand for a true incremental flag and the explicit i=?0 form for false.

priorityhttpheadersrfc9218http2http3extensible-priorities

How to use HTTP Priority Header (RFC 9218) Parser / Builder

  • 1.Set an urgency from 0 (most urgent) to 7 (least urgent), and/or toggle whether the response can be processed incrementally.
  • 2.Copy the generated Priority header value, with any field you left unchecked simply omitted so it falls back to its spec default.
  • 3.Paste an existing Priority header into the parser field to see its urgency and incremental fields, with defaults applied to whichever one was missing.

Frequently asked questions

What replaced the old HTTP/2 priority scheme?
RFC 9218 defines this Priority header (and an equivalent PRIORITY_UPDATE frame) as a simpler, extensible replacement for HTTP/2's original stream-dependency-and-weight priority tree, which was complex to implement correctly and mostly ignored by servers in practice.
What does the incremental flag actually do?
It tells the server the client can start using the response before it's fully complete, useful for something like a progressively rendered image. It's a hint, not a guarantee the server has to honor.
What happens if I omit a field?
Per RFC 9218, an omitted urgency defaults to 3 and an omitted incremental defaults to false. The parser applies these same defaults when a field is missing from the input.
Does this make a network request?
No, it only builds or parses the header value locally. It doesn't send a request or check what a real server or client does with the priority hint.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/priority-header \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"urgency":1,"incremental":true,"header":"u=1, i"}'

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