Convert produceBlockV4 to POST and round-trip Eth-Builder-Url (Gloas builder API 4/5) by ethDreamer · Pull Request #9806 · sigp/lighthouse

ethDreamer · 2026-08-13T20:15:08Z

Fourth PR of the Gloas builder API stack (beacon-APIs #630):

convert /eth/v4/validator/blocks/{slot} to POST with an optional
BuilderConfig body (min_bid, builder_boost_factor, direct builders)
add POST /eth/v1/validator/builder_preferences for forwarding signed
builder preferences
set Eth-Builder-Url on produceBlockV4 responses when a direct-builder bid
wins, accept it on POST /eth/v2/beacon/blocks, and forward the signed
block to that builder

The validator client still uses the legacy GET methods at this point; it
migrates in the final PR of this stack.

Depends-On: #9805

ethDreamer · 2026-08-13T20:15:14Z

This pull request is part of a Mergify stack:

#	Pull Request	Link
1	Add Gloas bid selection, block production, and bid gossip processing (Gloas builder API 3/5)	#9805
2	Convert produceBlockV4 to POST and round-trip Eth-Builder-Url (Gloas builder API 4/5)	#9806	👈
3	Migrate the validator client to the Gloas builder API (Gloas builder API 5/5)	#9807

ethDreamer · 2026-08-13T23:39:06Z

Revision history

#	Type	Changes	Reason	Date
1	initial	`c6cb1f0`		2026-08-13 23:38 UTC
2	content	`c6cb1f0 → 0ad508e`	catch up to Aug 10 beacon-APIs #630: require Eth-Consensus-Version on POST v4; 400 on zero-length url/auth-data in bodies; negative tests	2026-08-13 23:38 UTC
3	rebase	`0ad508e → 1541fc9` (rebase only)		2026-08-14 00:03 UTC
4	content	`1541fc9 → b75cd14`	rebase on unstable (#8907 SSZ responses): resolved import conflict in http_api validator/mod.rs	2026-08-14 18:25 UTC
5	rebase	`b75cd14 → d763878` (rebase only)		2026-08-17 16:52 UTC
6	rebase	`d763878 → 510daa9` (rebase only)		2026-08-18 17:51 UTC
7	rebase	`510daa9 → 9ffd62f` (rebase only)		2026-08-19 19:31 UTC
8	content	`9ffd62f → d6bc23f`	review response: 400 on oversize preferences body (4096-entry bound); rename fallout in tests	2026-08-19 21:57 UTC
9	rebase	`d6bc23f → f979c15` (rebase only)		2026-08-20 17:50 UTC
10	rebase	`f979c15 → f9c9f6b` (rebase only)		2026-08-20 21:41 UTC
11	rebase	`f9c9f6b → 275486f` (rebase only)		2026-08-20 23:35 UTC
12	rebase	`275486f → b659f44` (rebase only)		2026-08-21 14:14 UTC
13	rebase	`b659f44 → d1b834f` (rebase only)		2026-08-24 18:03 UTC
14	rebase	`d1b834f → 0e582da` (rebase only)		2026-08-25 17:47 UTC
15	rebase	`0e582da → 99bddcf` (rebase only)		2026-08-26 19:20 UTC
16	rebase	`99bddcf → f227c06` (rebase only)		2026-09-01 17:18 UTC
17	rebase	`f227c06 → 6359b33` (rebase only)		2026-09-01 18:32 UTC

chong-he

Looks good, just some nits. I also notice the comment (beacon-APIs #630) is mentioned too many times, would be good to clean them up

chong-he · 2026-08-21T02:23:34Z

+// Accepts the `BuilderPreferenceEntry` list as either JSON or SSZ, selected by the request's
+// `Content-Type` (`application/octet-stream` => SSZ, otherwise JSON). A required


Nit: comment like this maybe is not necessary?

Yeah agree, this is a fairly common pattern.

chong-he · 2026-08-21T02:26:37Z

+                .and_then(|content_type: Option<String>, body: Bytes| async move {
+                    let builder_config: BuilderConfig = if content_type.as_deref()
+                        == Some(SSZ_CONTENT_TYPE_HEADER)
+                    {
+                        BuilderConfig::from_ssz_bytes(&body).map_err(|e| {
+                            warp_utils::reject::custom_bad_request(format!("invalid SSZ: {e:?}"))
+                        })?
+                    } else {
+                        serde_json::from_slice(&body).map_err(|e| {
+                            warp_utils::reject::custom_deserialize_error(format!("{e:?}"))
+                        })?
+                    };


Both endpoints in this PR combines the request body of JSON and SSZ into one funciton, which is fine. The default is still JSON because if the header is not specified as application/octet-stream, then it goes to the else branch.

Just want to point out that I see in Lighthouse code base it is usually separate the JSON and SSZ request body into 2 functions, for example:

pub fn post_validator_proposer_preferences accepts the JSON request body

pub fn post_validator_proposer_preferences_ssz accepts the SSZ request body

Good point, but this is just one parameter in the post body.
I'm fine either way, I'll leave this to mark.

pawanjay176

This also looks good to me. Just one question mainly

pawanjay176 · 2026-08-25T02:46:19Z

+            warp::header::optional::<String>(CONTENT_TYPE_HEADER)
+                .and(warp::body::bytes())
+                .and_then(|content_type: Option<String>, body: Bytes| async move {
+                    let builder_config: BuilderConfig = if content_type.as_deref()


Isn't the builder_config optional?

pawanjay176 · 2026-08-25T22:47:21Z

+                .and_then(|content_type: Option<String>, body: Bytes| async move {
+                    let builder_config: BuilderConfig = if content_type.as_deref()
+                        == Some(SSZ_CONTENT_TYPE_HEADER)
+                    {
+                        BuilderConfig::from_ssz_bytes(&body).map_err(|e| {
+                            warp_utils::reject::custom_bad_request(format!("invalid SSZ: {e:?}"))
+                        })?
+                    } else {
+                        serde_json::from_slice(&body).map_err(|e| {
+                            warp_utils::reject::custom_deserialize_error(format!("{e:?}"))
+                        })?
+                    };


Good point, but this is just one parameter in the post body.
I'm fine either way, I'll leave this to mark.

pawanjay176 · 2026-08-25T22:47:51Z

+// Accepts the `BuilderPreferenceEntry` list as either JSON or SSZ, selected by the request's
+// `Content-Type` (`application/octet-stream` => SSZ, otherwise JSON). A required


Yeah agree, this is a fairly common pattern.

…builder API 4/5) Fourth PR of the Gloas builder API stack (beacon-APIs #630): - convert `/eth/v4/validator/blocks/{slot}` to POST with an optional `BuilderConfig` body (min_bid, builder_boost_factor, direct builders) - add `POST /eth/v1/validator/builder_preferences` for forwarding signed builder preferences - set `Eth-Builder-Url` on produceBlockV4 responses when a direct-builder bid wins, accept it on `POST /eth/v2/beacon/blocks`, and forward the signed block to that builder The validator client still uses the legacy GET methods at this point; it migrates in the final PR of this stack. Change-Id: I0ad30b8f36ad9b588ea1a0398220f92c9597bb95

ethDreamer mentioned this pull request Aug 13, 2026

Gloas: external builder API (payload bid selection and block production) #9757

Draft

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from c6cb1f0 to 0ad508e Compare August 13, 2026 23:39

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from 0ad508e to 1541fc9 Compare August 14, 2026 00:03

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from 1541fc9 to b75cd14 Compare August 14, 2026 18:25

chong-he self-requested a review August 17, 2026 06:44

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from b75cd14 to d763878 Compare August 17, 2026 16:52

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from d763878 to 510daa9 Compare August 18, 2026 17:51

eserilev mentioned this pull request Aug 19, 2026

glamsterdam-devnet-8 #9881

Draft

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from 510daa9 to 9ffd62f Compare August 19, 2026 19:31

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch 2 times, most recently from d6bc23f to f979c15 Compare August 20, 2026 17:50

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from f979c15 to f9c9f6b Compare August 20, 2026 21:41

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from f9c9f6b to 275486f Compare August 20, 2026 23:35

chong-he reviewed Aug 21, 2026

View reviewed changes

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch 2 times, most recently from b659f44 to d1b834f Compare August 24, 2026 18:03

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from d1b834f to 0e582da Compare August 25, 2026 17:47

pawanjay176 approved these changes Aug 25, 2026

View reviewed changes

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from 0e582da to 99bddcf Compare August 26, 2026 19:20

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from 99bddcf to f227c06 Compare September 1, 2026 17:18

ethDreamer force-pushed the stack/ethDreamer/gloas-builder-api-stacked/convert-produceblockv4-post-round-trip-eth--0ad30b8f branch from f227c06 to 6359b33 Compare September 1, 2026 18:32

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Convert produceBlockV4 to POST and round-trip Eth-Builder-Url (Gloas builder API 4/5) - #9806

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