--- title: HTTP Message Signatures with curl | daily.dev description: curl now experimentally supports HTTP Message Signatures as defined in RFC 9421, starting with the upcoming 8.22.0 release. The feature enables digital signing... canonical: https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: HTTP Message Signatures with curl | daily.dev og:description: curl now experimentally supports HTTP Message Signatures as defined in RFC 9421, starting with the upcoming 8.22.0 release. The feature enables digital signing... og:url: https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp og:image: https://api.daily.dev/og/posts/eDE6ylMsp.png og:image:alt: HTTP Message Signatures with curl og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # HTTP Message Signatures with curl **[daniel.haxx.se](https://daily.dev/sources/danielhaxxse)** · 3 min read · 12 upvotes · 1 comments ## Summary curl now experimentally supports HTTP Message Signatures as defined in RFC 9421, starting with the upcoming 8.22.0 release. The feature enables digital signing of selected HTTP request components (headers, method, path, etc.) to ensure they arrive unmodified through proxies, CDNs, and other intermediaries. Four new command-line options are introduced: --httpsig-algo (defaulting to ed25519, with hmac-sha256 also supported), --httpsig-key, --httpsig-keyid, and --httpsig-headers. Equivalent libcurl options are available via curl_easy_setopt. The feature is marked experimental, must be explicitly enabled at build time, and backward compatibility is not guaranteed until it exits the experimental phase. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [curl 8.22.0](https://daily.dev/posts/curl-8-22-0-ovkooqlqx) · daniel.haxx.se · 4 upvotes · 0 comments - [curl 8.21.0](https://daily.dev/posts/curl-8-21-0-nk89ow7op) · daniel.haxx.se · 6 upvotes · 0 comments --- Tags: [#curl](https://daily.dev/tags/curl) [View this post on daily.dev](https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"HTTP Message Signatures with curl","url":"https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/http-message-signatures-with-curl-ede6ylmsp"},"datePublished":"2026-07-27T06:59:51.383Z","dateModified":"2026-07-27T07:00:10.793Z","description":"curl now experimentally supports HTTP Message Signatures as defined in RFC 9421, starting with the upcoming 8.22.0 release. 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