# Web Bot Auth HTTP Message Signatures WebBotAuth

[2 · Identify](/category/identify/)

| Web Bot Auth HTTP Message Signatures |
| --- |
| Category | [Identify](/category/identify/) |
| Governed by | IETF webbotauth Working Group (chartered; document adopted as a WG item 2026-09-01) |
| Status | Active Internet-Draft, WG Document, Intended Status: Informational |
| Phase | working group |
| Implementation | multi-implementation |
| Adoption | observed — Cloudflare (edge verification, verified-bots program) and independent client/server implementations listed in the draft's own appendix |
| Version | draft-ietf-webbotauth-httpsig-protocol-00, adopted by the webbotauth WG, last updated 2026-09-01 (supersedes the individual draft-meunier-webbotauth-httpsig-protocol-00 of 2026-06-26) (2026-09-01) |
| Specification | [https://datatracker.ietf.org/doc/draft-ietf-webbotauth-httpsig-protocol/](https://datatracker.ietf.org/doc/draft-ietf-webbotauth-httpsig-protocol/) |
| Found at | /.well-known/http-message-signatures-directory |
| Last checked | 2026-09-06 |

[Identify](/category/identify/) Web Bot Auth is an IETF specification that lets an automated HTTP client (a crawler, agent, or bot) cryptographically sign its outbound requests using RFC 9421 HTTP Message Signatures, so the receiving server can verify the client's identity and intent without relying on spoofable signals like the User-Agent string or source IP [[1]](#ref-1). A client sends a Signature-Agent header naming where its public keys can be found; the origin resolves that to a JSON Web Key Set served at a fixed well-known path and verifies the request's Signature/Signature-Input fields against it [[1]](#ref-1).

## Overview
It solves bot/agent attribution at the transport layer: an origin can distinguish a signed, identity-bearing automated client from unsigned traffic, and can grant differentiated treatment (rate limits, access, billing) based on a verified identity rather than heuristics [[1]](#ref-1)[[3]](#ref-3). It does not define what a client is authorized to do once verified (that is left to the origin's own policy), does not cover payment, and does not itself specify how a verifier should be told which identities to trust — that is the job of the companion Signature Agent Card / registry draft.

Current state: originally an individual submission (draft-meunier-webbotauth-httpsig-protocol, first published 2025-04, reaching -00 of the current "httpsig-protocol" naming on 2026-06-26). On 2026-09-01 it was formally adopted as a document of the newly chartered IETF webbotauth Working Group, republished as draft-ietf-webbotauth-httpsig-protocol-00 [[2]](#ref-2). Intended status is Informational, not yet a Working Group last call or RFC.

Who implements it: Cloudflare verifies Web Bot Auth signatures at the edge for its Verified Bots program and publishes an integration guide with the exact required headers and the /.well-known/http-message-signatures-directory path [[3]](#ref-3). The draft's own appendix lists further independent implementations: a Chrome MV3 extension and Rust/TypeScript libraries from Cloudflare, a Puppeteer-based client example, a PHP Guzzle middleware, Python scripts, and server-side modules for Caddy and Apache [[1]](#ref-1). Cloudflare previously reported signing bots from OpenAI as an early adopter (2025-05-15, per the prior seed research; not independently re-verified in this pass).

Disputed or unknown: the spec's naming and draft numbering have churned repeatedly (it replaces draft-meunier-web-bot-auth-architecture and draft-meunier-webbotauth-httpsig-directory), which makes citing a stable version number difficult; always resolve to the datatracker's "current" redirect rather than a pinned draft-NN URL. Adoption beyond Cloudflare's own edge and the listed open-source projects has not been independently counted.

## Discovery and probe

Signature-Agent HTTP header points to a key directory; the directory is fetched from a fixed well-known path · /.well-known/http-message-signatures-directory

```
GET https://{origin}/.well-known/http-message-signatures-directory
parse:     200 response with Content-Type: application/http-message-signatures-directory+json and a JWKS body ({"keys":[...]}), itself signed with a Signature/Signature-Input pair tagged http-message-signatures-directory
on absent: No published key directory; the origin cannot verify Web Bot Auth signatures from this Signature-Agent identity
```

Live check run by [the MCP probe](/mcp/server-card): GET /.well-known/http-message-signatures-directory. A signature directory is a JWKS served with its own media type.

```
{
 "path": "/.well-known/http-message-signatures-directory",
 "expect": {
  "content_type": "http-message-signatures-directory",
  "json_keys": [
   "keys"
  ]
 },
 "note": "A signature directory is a JWKS served with its own media type."
}
```

## History
- 2026-09-05 — seeded from Exa Agent research run
- 2026-09-06 — verified against draft-meunier-webbotauth-httpsig-protocol-00, its WG-adopted successor draft-ietf-webbotauth-httpsig-protocol-00 (2026-09-01), and Cloudflare's Web Bot Auth integration docs

## Instances

- [web-bot-auth-example (Puppeteer script)](https://github.com/stytchauth/web-bot-auth-example) · Recorded 2026-09-06 · service
- [web-bot-auth-apache (Apache module, C)](https://github.com/garyillyes/web-bot-auth-apache) · Recorded 2026-09-06 · service
- [guzzle-web-bot-auth-middleware (PHP)](https://github.com/olipayne/guzzle-web-bot-auth-middleware) · Recorded 2026-09-06 · service
- [cloudflare/web-bot-auth (Chrome MV3, Cloudflare Workers, Rust binaries, server verifier)](https://github.com/cloudflare/web-bot-auth) · Recorded 2026-09-06 · service
- [Bot-Authentication (Python)](https://github.com/cyberstormdotmu/bot-authentication) · Recorded 2026-09-06 · service
- [AWS WAF](https://aws.amazon.com/waf/) · Observed 2026-08-03 · service
- [Akamai](https://www.akamai.com) · Observed 2026-07-06 · service
- [Cloudflare (edge verifier and Verified Bots program)](https://developers.cloudflare.com/bots/reference/bot-verification/web-bot-auth/) · Observed 2026-07-01 · business
- [wba (managed Web Bot Auth directory server)](https://github.com/calvernaz/wba) · Observed 2026-04-13 · service

Every instance with its source is listed on the [instances page](/instances/).

## See also

- [Signature Agent Card (Web Bot Auth registry)](/protocols/web-bot-auth-signature-agent-card/)
- [HTTP Message Signatures](/protocols/http-message-signatures/)

## References

- The protocol defines the Signature-Agent header (profiling RFC 9421's Signature-Input/Signature fields) for in-band key discovery, and a well-known URI serving a JWKS-based key directory. The draft's own appendix lists independent public client implementations (Chrome MV3 and Cloudflare Workers/Rust libraries by Cloudflare, a Puppeteer example, a Guzzle/PHP middleware, Python scripts) and server implementations (Cloudflare Workers, a Caddy plugin, an Apache module). — [https://datatracker.ietf.org/doc/html/draft-meunier-webbotauth-httpsig-protocol-00](https://datatracker.ietf.org/doc/html/draft-meunier-webbotauth-httpsig-protocol-00) (2026-06-26) VERIFIED
- As of 2026-09-01 the document was adopted by the IETF webbotauth Working Group as draft-ietf-webbotauth-httpsig-protocol-00, superseding the individual submission — [https://datatracker.ietf.org/doc/draft-ietf-webbotauth-httpsig-protocol/](https://datatracker.ietf.org/doc/draft-ietf-webbotauth-httpsig-protocol/) (2026-09-01) VERIFIED
- Cloudflare verifies Web Bot Auth signatures at the edge as part of its Verified Bots program, requiring the key directory at /.well-known/http-message-signatures-directory and specific Signature-Input parameters (tag=web-bot-auth, keyid, created, expires) — [https://developers.cloudflare.com/bots/reference/bot-verification/web-bot-auth/](https://developers.cloudflare.com/bots/reference/bot-verification/web-bot-auth/) (2026-07-01) VERIFIED

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