---
title: "PUT /v2/chats/{chat_id}/delivered"
method: PUT
path: "/v2/chats/{chat_id}/delivered"
tags: ["Messaging"]
---

# PUT /v2/chats/{chat_id}/delivered

`PUT /v2/chats/{chat_id}/delivered`

## Request

- Base URL: `https://api.arbital.xyz` (the document declares no server; this is the origin it was published from)
- URL: `https://api.arbital.xyz/v2/chats/{chat_id}/delivered`
- Auth: HTTP bearer

Explicit device acknowledgement that messages up to the sequence were received. Lower or equal values are no-ops; a sequence past the latest committed message is 400 sequence_out_of_range. Never derived from push-provider receipts.

## Path parameters

- `chat_id` string, uuid, required

## Request body

- SetChatDeliveredRequest
  - `last_delivered_sequence` string, required

## Response `200`

Monotonic delivered watermark for the authenticated chat member

- ChatReadState: A member's acknowledgement watermarks. Sent = committed message. Delivered = the member's device acknowledged receipt of messages up to the sequence. Read follows visibility and implies delivered. Both are monotonic per member and never come from push-provider receipts.
  - `chat_id` string, uuid, required
  - `last_read_sequence` string, required
  - `updated_at_unix_ms` integer, required
  - `user_id` string, uuid, required
  - `last_delivered_sequence` string, required: Explicit device acknowledgement watermark; never below last_read_sequence.
  - `delivered_at_unix_ms` integer, nullable, required: When the delivered watermark last advanced; null before any acknowledgement.
  - `read_at_unix_ms` integer, nullable, required

## Other responses

- `400`: Stable machine-readable private messaging problem
- `401`: Stable machine-readable private messaging problem
- `403`: Stable machine-readable private messaging problem
- `404`: Stable machine-readable private messaging problem
- `409`: Stable machine-readable private messaging problem
- `429`: Authenticated messaging mutation budget exhausted
- `503`: Stable machine-readable private messaging problem

---

[API](https://skmtc.dev/arbital/apis/arbital-api.md) - [All operations](https://skmtc.dev/arbital/apis/arbital-api/llms.txt) - [OpenAPI document](https://skmtc.dev/arbital/apis/arbital-api/revisions/bb0185edf43a?raw)