---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Long: http2-prior-knowledge
Tags: Versions
Protocols: HTTP
Added: 7.49.0
Mutexed: http1.1 http1.0 http2 http3
Requires: HTTP/2
Help: Use HTTP 2 without HTTP/1.1 Upgrade
Category: http
Multi: boolean
See-also:
  - http2
  - http3
Example:
  - --http2-prior-knowledge $URL
---

# `--http2-prior-knowledge`

Issue a non-TLS HTTP requests using HTTP/2 directly without HTTP/1.1 Upgrade.
It requires prior knowledge that the server supports HTTP/2 straight away.
HTTPS requests still do HTTP/2 the standard way with negotiated protocol
version in the TLS handshake.