---
title: "Record Response Timing"
method: POST
path: "/api/chats/{chat_id}/messages/{message_id}/response-timing"
tags: ["chats"]
---

# Record Response Timing

`POST /api/chats/{chat_id}/messages/{message_id}/response-timing`

## Request

- Base URL: `https://app.thinqos.com` (the document declares no server; this is the origin it was published from)
- URL: `https://app.thinqos.com/api/chats/{chat_id}/messages/{message_id}/response-timing`
- Auth: none declared

Record a viewer's browser timing and displayed estimate observations for a
retained assistant response. This requires existing chat access, is private
to the effective viewer and cannot establish authoritative server timing or
train estimate cohorts. Reusing an observation ID returns its first receipt.

## Path parameters

- `chat_id` string, uuid, required
- `message_id` string, uuid, required

## Headers

- `x-impersonate-identity-id` string, nullable

## Request body

- ResponseTimingObservation
  - `observation_id` string, uuid, required
  - `send_to_first_visible_us` integer, nullable
  - `send_to_answer_complete_us` integer, required
  - `source` 'browser_monotonic'
  - `resolution_us` 1000
  - `displayed_estimates` DisplayedEstimate[]
    - `activity_id` string, required
    - `label` string, required
    - `observed_after_send_us` integer, required
    - `lower_seconds` number, required
    - `upper_seconds` number, required
    - `estimate_observed_at` string, required
    - `cohort_version` string, nullable
    - `cohort_scope` string, nullable
    - `sample_size` integer, nullable

## Response `200`

Successful Response

- BrowserTiming
  - `send_to_first_visible_us` integer, nullable
  - `send_to_answer_complete_us` integer, required
  - `observation_id` string, required
  - `source` string
  - `resolution_us` integer
  - `evidence` string
  - `completion_evidence` string
  - `displayed_estimates` DisplayedEstimate[]
    - `activity_id` string, required
    - `label` string, required
    - `observed_after_send_us` integer, required
    - `lower_seconds` number, required
    - `upper_seconds` number, required
    - `estimate_observed_at` string, required
    - `cohort_version` string, nullable
    - `cohort_scope` string, nullable
    - `sample_size` integer, nullable

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/thinqos/apis/thinqos-api.md) · [All operations](https://skmtc.dev/thinqos/apis/thinqos-api/llms.txt) · [OpenAPI document](https://skmtc.dev/thinqos/apis/thinqos-api/revisions/ce2c2ce318b1?raw)