diff --git a/apis/builder/beacon_block.yaml b/apis/builder/beacon_block.yaml
new file mode 100644
index 0000000..6e9ddd8
--- /dev/null
+++ b/apis/builder/beacon_block.yaml
@@ -0,0 +1,54 @@
+post:
+  operationId: "submitSignedBeaconBlock"
+  summary: Submit a signed beacon block with the execution payload bid.
+  description: |
+    Submits a `SignedBeaconBlock` and `SignedBlindedExecutionPayloadEnvelope` to the builder, 
+    binding the proposer to the bid. 
+
+    A success response (200) indicates that the signed beacon block was
+    valid. If the signed beacon block was invalid, then the builder
+    must return an error response (400) with a description of the validation
+    failure.
+  tags:
+    - Builder
+  parameters:
+    - in: header
+      schema:
+        $ref: "../../builder-oapi.yaml#/components/schemas/ConsensusVersion"
+      required: false
+      name: Eth-Consensus-Version
+      description: "The active consensus version to which the block being submitted belongs. Required if request is SSZ encoded."
+  requestBody:
+    description: A `SignedBeaconBlock`.
+    required: true
+    content:
+      application/json:
+        schema:
+          type: object
+          required: [block]
+          properties:
+            block:
+              $ref: "../../beacon-apis/types/gloas/block.yaml#/Gloas/SignedBeaconBlock"
+              description: "The signed beacon block."
+            blinded_envelope:
+              $ref: "../../types/gloas/blinded_execution_payload_envelope.yaml#/Gloas/SignedBlindedExecutionPayloadEnvelope"
+              description: "The signed blinded execution payload envelope."
+      application/octet-stream:
+        schema:
+          description: "SSZ serialized `SignedBeaconBlock` bytes. Use content type header to indicate that SSZ data is contained in the request body."
+  responses:
+    "202":
+      description: Success response.
+    "400":
+      description: Error response.
+      content:
+        application/json:
+          schema:
+            $ref: "../../builder-oapi.yaml#/components/schemas/ErrorMessage"
+          example:
+            code: 400
+            message: "Invalid signed block and envelope root: missing signature"
+    "415":
+      $ref: "../../builder-oapi.yaml#/components/responses/UnsupportedMediaType"
+    "500":
+      $ref: "../../builder-oapi.yaml#/components/responses/InternalError"
diff --git a/apis/builder/execution_payload_bid.yaml b/apis/builder/execution_payload_bid.yaml
new file mode 100644
index 0000000..2d6ad4f
--- /dev/null
+++ b/apis/builder/execution_payload_bid.yaml
@@ -0,0 +1,97 @@
+get:
+  operationId: "getExecutionPayloadBid"
+  summary: Get an execution payload bid.
+  description: |
+    Requests a builder node to produce a valid execution payload bid, which
+    can be integrated into a blinded beacon block and signed.
+
+    If the builder is unable to produce a valid execution payload bid, then
+    the builder MUST return a 204 response. If the request is invalid, then the
+    builder MUST return an error response (400) with a description of the
+    validation failure.
+
+    This API is applicable from Glamsterdam fork onwards.
+  tags:
+    - Builder
+  parameters:
+    - name: slot
+      in: path
+      required: true
+      description: The slot for which the block should be proposed.
+      schema:
+        $ref: "../../builder-oapi.yaml#/components/schemas/Uint64"
+    - name: parent_hash
+      in: path
+      required: true
+      description: Hash of execution layer block the proposer will build on.
+      schema:
+        $ref: "../../builder-oapi.yaml#/components/schemas/Root"
+    - name: pubkey
+      in: path
+      required: true
+      description: The validator's BLS public key.
+      schema:
+        $ref: "../../builder-oapi.yaml#/components/schemas/Pubkey"
+    - name: Date-Milliseconds
+      in: header
+      required: false
+      description: |
+        Optional header containing a Unix timestamp in milliseconds representing
+        the point-in-time the request was sent. This header can be used to measure
+        latency.
+      schema:
+        type: integer
+        format: int64
+        example: 1710338135000
+    - name: X-Timeout-Ms
+      in: header
+      required: false
+      description: |
+        Optional header containing the proposer's timeout for the request in milliseconds. 
+        Relays should use this header to adjust the amount of time by which they delay getBid 
+        requests to maximise block rewards. Otherwise, getBid requests will timeout and the proposer 
+        will not receive the header in time.
+      schema:
+        type: integer
+        format: int64
+        example: 10000
+  responses:
+    "200":
+      description: Success response.
+      headers:
+        Eth-Consensus-Version:
+          $ref: "../../builder-oapi.yaml#/components/headers/Eth-Consensus-Version"
+          required: false
+      content:
+        application/json:
+          schema:
+            title: GetExecutionPayloadBidResponse
+            type: object
+            required: [version, data]
+            properties:
+              version:
+                type: string
+                enum: [ gloas ]
+                example: "gloas"
+              data:
+                $ref: "../../types/gloas/bid.yaml#/Gloas/SignedBuilderBid"
+        application/octet-stream:
+          schema:
+            description: "SSZ serialized `SignedBuilderBid` bytes. Use Accept header to choose this response type"
+    "204":
+      description: No header is available.
+    "400":
+      description: Error response.
+      content:
+        application/json:
+          schema:
+            $ref: "../../builder-oapi.yaml#/components/schemas/ErrorMessage"
+          examples:
+            InvalidRequest:
+              value:
+                code: 400
+                message: "Unknown hash: missing parent hash"
+    "406":
+      $ref: "../../builder-oapi.yaml#/components/responses/NotAcceptable"
+    "500":
+      $ref: "../../builder-oapi.yaml#/components/responses/InternalError"
diff --git a/beacon-apis b/beacon-apis
index 69d2feb..8d90551 160000
--- a/beacon-apis
+++ b/beacon-apis
@@ -1 +1 @@
-Subproject commit 69d2feb12a6047c4f21e628dea8b0135b7e9013a
+Subproject commit 8d9055187f5a8b8ed89b2160d9718eaa0c955726
diff --git a/builder-oapi.yaml b/builder-oapi.yaml
index a9c05f0..dcfe7e0 100644
--- a/builder-oapi.yaml
+++ b/builder-oapi.yaml
@@ -53,6 +53,10 @@ paths:
     $ref: "./apis/builder/validators.yaml"
   /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey}:
     $ref: "./apis/builder/header.yaml"
+  /eth/v1/builder/execution_payload_bid/{slot}/{parent_hash}/{pubkey}:
+    $ref: "./apis/builder/execution_payload_bid.yaml"
+  /eth/v1/builder/beacon_block:
+    $ref: "./apis/builder/beacon_block.yaml"
   /eth/v1/builder/blinded_blocks:
     $ref: "./apis/builder/blinded_blocks.yaml"
   /eth/v2/builder/blinded_blocks:
@@ -72,7 +76,7 @@ components:
       $ref: "./beacon-apis/types/http.yaml#/ErrorMessage"
     ConsensusVersion:
       $ref: "./beacon-apis/beacon-node-oapi.yaml#/components/schemas/ConsensusVersion"
-      enum: [bellatrix, capella, deneb, electra, fulu]
+      enum: [bellatrix, capella, deneb, electra, fulu, gloas]
       example: "bellatrix"
     Bellatrix.ExecutionPayload:
       $ref: "./beacon-apis/types/bellatrix/execution_payload.yaml#/Bellatrix/ExecutionPayload"
@@ -102,6 +106,8 @@ components:
       $ref: "./types/fulu/blobs_bundle.yaml#/Fulu/BlobsBundle"
     Fulu.ExecutionPayloadAndBlobsBundle:
       $ref: "./types/fulu/execution_payload_and_blobs_bundle.yaml#/Fulu/ExecutionPayloadAndBlobsBundle"
+    Gloas.SignedBuilderBid:
+      $ref: "./types/gloas/bid.yaml#/Gloas/SignedBuilderBid"
 
   responses:
     InternalError:
diff --git a/specs/gloas/builder.md b/specs/gloas/builder.md
new file mode 100644
index 0000000..7c1a7b6
--- /dev/null
+++ b/specs/gloas/builder.md
@@ -0,0 +1 @@
+# Gloas - Builder Specification
\ No newline at end of file
diff --git a/specs/gloas/validator.md b/specs/gloas/validator.md
new file mode 100644
index 0000000..75315f8
--- /dev/null
+++ b/specs/gloas/validator.md
@@ -0,0 +1,84 @@
+<!-- START doctoc generated TOC please keep comment here to allow auto update -->
+<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
+**Table of Contents**  *generated with [DocToc](https://github.com/thlorenz/doctoc)*
+
+- [Gloas - Honest Validator](#gloas---honest-validator)
+  - [Introduction](#introduction)
+  - [Containers](#containers)
+    - [New Containers](#new-containers)
+    - [`BlindedExecutionPayloadEnvelope`](#blindedexecutionpayloadenvelope)
+    - [Extended Containers](#extended-containers)
+    - [`BuilderBid`](#builderbid)
+    - [Block proposal](#block-proposal)
+      - [Constructing the `BeaconBlockBody`](#constructing-the-beaconblockbody)
+        - [ExecutionPayloadBid](#executionpayloadbid)
+
+<!-- END doctoc generated TOC please keep comment here to allow auto update -->
+
+# Gloas - Honest Validator
+
+
+## Introduction
+
+This document explains how a beacon-chain validator can participate in the external block building market post ePBS. 
+
+Validators request an `ExecutionPayloadBid` from the external builder network to put it in their `SignedBeaconBlock`. The external builder network broadcasts the `SignedExecutionPayloadEnvelope` corresponding to the bid to the PTC commitee. 
+
+## Containers
+
+### New Containers
+
+### `BlindedExecutionPayloadEnvelope`
+
+```python
+class BlindedExecutionPayloadEnvelope(Container):
+    payload_root: Root
+    execution_requests_root: Root
+    builder_index: ValidatorIndex
+    beacon_block_root: Root
+    slot: Slot
+    blob_kzg_commitments_root: Root
+    state_root: Root
+```
+
+```python
+class SignedBlindedExecutionPayloadEnvelope(Container):
+    message: BlindedExecutionPayloadEnvelope
+    signature: Signature
+```
+
+### Extended Containers
+
+### `BuilderBid`
+
+```python
+class BuilderBid(Container):
+    bid: ExecutionPayloadBid
+    payload_root: Root
+    execution_requests_root: Root
+    pubkey: BLSPubkey
+```
+
+### Block proposal
+
+#### Constructing the `BeaconBlockBody`
+
+##### ExecutionPayloadBid
+
+To obtain an execution payload, a block proposer building a block on top of a beacon `state` in a given `slot` must take
+the following actions:
+
+1. Call upstream builder software to get an `ExecutionPayloadBid` and the roots of the `payload` and `execution_requests`
+   with the required data `slot`, `parent_hash` and `pubkey`, where:
+   * `slot` is the proposal's slot
+   * `parent_hash` is the value `state.latest_execution_payload_header.block_hash`
+   * `pubkey` is the proposer's public key
+2. Assemble a `SignedBeaconBlock` according to the process outlined in the [Gloas specs][gloas-specs] but with
+   the `ExecutionPayloadBid` from the prior step.
+3. The proposer assembles a `SignedBlindedExecutionPayloadEnvelope` with the `payload` and `execution_requests` roots provided 
+   from the prior step.
+4. The proposer returns the `SignedBeaconBlock` and `SignedBlindedExecutionPayloadEnvelope` back to the upstream block
+   building software.
+5. The upstream block building software constructs the `SignedExecutionPayloadEnvelope` from the
+   `SignedBlindedExecutionPayloadEnvelope` and broadcasts it to the PTC commitee.
+
diff --git a/types/gloas/bid.yaml b/types/gloas/bid.yaml
new file mode 100644
index 0000000..a5c3272
--- /dev/null
+++ b/types/gloas/bid.yaml
@@ -0,0 +1,24 @@
+Gloas:
+  BuilderBid:
+    type: object
+    description: "The `BuilderBid` object from the Builder API spec. The bid is signed by the builder BLS key."
+    required: [execution_payload_bid]
+    properties:
+      execution_payload_bid:
+        $ref: "../../beacon-apis/types/gloas/execution_payload_bid.yaml#/Gloas/ExecutionPayloadBid"
+      payload_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the execution payload"
+      execution_requests_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the execution requests"
+
+  SignedBuilderBid:
+    type: object
+    description: "The `SignedBuilderBid` object from the Builder API spec. The bid is signed by the builder BLS key."
+    required: [message, signature]
+    properties:
+      message:
+        $ref: "#/Gloas/BuilderBid"
+      signature:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Signature"
diff --git a/types/gloas/blinded_execution_payload_envelope.yaml b/types/gloas/blinded_execution_payload_envelope.yaml
new file mode 100644
index 0000000..c94d29e
--- /dev/null
+++ b/types/gloas/blinded_execution_payload_envelope.yaml
@@ -0,0 +1,36 @@
+Gloas:
+  BlindedExecutionPayloadEnvelope:
+    type: object
+    description: "The `BlindedExecutionPayloadEnvelope` object from the Builder API spec. The execution payload envelope is blinded by the builder BLS key."
+    required: [payload, execution_requests, builder_index, beacon_block_root, slot, blob_kzg_commitments_root, state_root]
+    properties:
+      payload_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the execution payload"
+      execution_requests_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the execution requests"
+      builder_index:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Uint64"
+        description: "Index of the builder that created this execution payload envelope"
+      beacon_block_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the beacon block for this payload"
+      slot:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Uint64"
+        description: "Slot number for this execution payload"
+      blob_kzg_commitments_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Root of the blob KZG commitments"
+      state_root:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Root"
+        description: "Beacon state root after executing this payload"
+  SignedBlindedExecutionPayloadEnvelope:
+    type: object
+    description: "The `SignedBlindedExecutionPayloadEnvelope` object from the Builder API spec. The execution payload envelope is signed by the proposer's BLS key."
+    required: [message, signature]
+    properties:
+      message:
+        $ref: "#/Gloas/BlindedExecutionPayloadEnvelope"
+      signature:
+        $ref: "../../beacon-apis/types/primitive.yaml#/Signature"
\ No newline at end of file