Add builder API types, request-auth domain, and eth2 client methods (Gloas builder API 1/5)

[ethDreamer]

First PR of the Gloas builder API stack (builder-specs #165 / beacon-APIs #630):

• consensus/types: DOMAIN_REQUEST_AUTH application domain and get_request_auth_domain()
• common/builder_types: new crate with the shared Builder API wire types
• common/eth2: POST produceBlockV4 methods, builder-preferences methods,
  Eth-Builder-Url header plumbing, and ProduceBlockV4Metadata::builder_url

All changes are additive: the legacy GET v4 block-production methods are kept
alongside the new POST variants until the validator client migrates later in
this stack, then removed in the final PR.

[ethDreamer]

This pull request is part of a Mergify stack:

#	Pull Request	Link
1	Add builder API types, request-auth domain, and eth2 client methods (Gloas builder API 1/5)	#9803	👈
2	Add Gloas Builder API client and adapt execution layer (Gloas builder API 2/5)	#9804
3	Add Gloas bid selection, block production, and bid gossip processing (Gloas builder API 3/5)	#9805
4	Convert produceBlockV4 to POST and round-trip Eth-Builder-Url (Gloas builder API 4/5)	#9806
5	Migrate the validator client to the Gloas builder API (Gloas builder API 5/5)	#9807

[ethDreamer]

Revision history

#	Type	Changes	Reason	Date
1	initial	088ad76		2026-08-13 23:38 UTC
2	content	088ad76 → 6f6c368	catch up to Aug 10 spec revisions: builder_pubkeys list (was single builder_pubkey), zero-length url/auth-data validation, fork_name param + Eth-Consensus-Version on POST v4 client (hoisted into the …	2026-08-13 23:38 UTC
3	content	6f6c368 → 7e94d7b	fix clippy: useless same-type .into() in test helper	2026-08-14 00:03 UTC
4	rebase	7e94d7b → 6e51496 (rebase only)		2026-08-14 18:25 UTC
5	rebase	6e51496 → 3e64b04 (rebase only)		2026-08-17 16:52 UTC
6	rebase	3e64b04 → 8e5b90a (rebase only)		2026-08-18 17:51 UTC
7	rebase	8e5b90a → 766aa4e (rebase only)		2026-08-19 19:31 UTC
8	content	766aa4e → 5609394	review response: rename post_validator_blocks_v4_path (verb was a GET-era fossil), builder_url max-size test + compile-time MaxDataSize invariant, BuilderConfig doc rewrite (fully-resolved / not-defa…	2026-08-19 21:57 UTC
9	rebase	5609394 → d68a341 (rebase only)		2026-08-20 17:50 UTC
10	rebase	d68a341 → 885b2f8 (rebase only)		2026-08-20 21:41 UTC

[ethDreamer]

[pawanjay176]

Looking good. Mostly nits

[pawanjay176]

Is this enforced somewhere else?

[ethDreamer]

It's enforced in the fn validate() on BuilderEntry:

  pub fn validate(&self) -> Result<(), &'static str> {
      if self.url.as_bytes().is_empty() {
          return Err("zero-length builder url");
      }
      if self.auth.message.data.is_empty() {
          return Err("zero-length auth data");
      }
      Ok(())
  }

and the same validate() function is used on BuilderPreferenceEntry and it's enforced in the HTTP API:

• File: beacon_node/http_api/src/validator/mod.rs:547-553
• Added in PR: Convert produceBlockV4 to POST and round-trip Eth-Builder-Url (Gloas builder API 4/5) #9806

for entry in builder_config.builders.iter() {
    entry.validate().map_err(|e| {
        warp_utils::reject::custom_bad_request(format!(
            "invalid builder entry: {e}"
        ))
    })?;
}

and that PR adds a test for the http api at beacon_node/http_api/tests/tests.rs:5107 that explicitly tests the http api rejects it.

[pawanjay176]

Looks good

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Some required checks have failed. Could you please take a look @ethDreamer? 🙏

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-08-20 22:37 UTC · Rule: default · triggered by the @mergifyio queue command
• ✅ Checks passed · on draft merge queue: checking unstable (6e1fae3) and [#9803 + #9804] together #9901
• ✅ Merged — 2026-08-20 23:09 UTC · at 885b2f8845f6f056db81934866f8fd217fda6e90 · squash

This pull request spent 32 minutes 2 seconds in the queue, including 29 minutes 9 seconds running CI.

Required conditions to merge

• check-success=local-testnet-success
• check-success=test-suite-success
• depends-on=sigp/lighthouse#9803 [⛓️ Add builder API types, request-auth domain, and eth2 client methods (Gloas builder API 1/5) #9803 [stack]]
  • Add builder API types, request-auth domain, and eth2 client methods (Gloas builder API 1/5) #9803
  • Add Gloas Builder API client and adapt execution layer (Gloas builder API 2/5) #9804
• github-review-approved [🛡 GitHub branch protection]
  • Add builder API types, request-auth domain, and eth2 client methods (Gloas builder API 1/5) #9803
  • Add Gloas Builder API client and adapt execution layer (Gloas builder API 2/5) #9804