---
title: "Measure the experiment and record the look"
method: GET
path: "/api/v1/experiments/{experiment_id}/readout"
tags: ["experiments"]
---

# Measure the experiment and record the look

`GET /api/v1/experiments/{experiment_id}/readout`

## Request

- Base URL: `https://api.outrival.com` (the document declares no server; this is the origin it was published from)
- URL: `https://api.outrival.com/api/v1/experiments/{experiment_id}/readout`
- Auth: HTTP bearer

The full readout, and the peek row that records having looked at it.

THE PEEK IS PERSISTED. The decision threshold this engine ships is
calibrated for weekly looks and this endpoint is unthrottled, so the log is
the only thing that can ever say whether that caveat held — and it is what
makes the guardrail persistence rule computable at all. A look that could
not produce a number (a draft, or an experiment with no control group) comes
back ``readable: false`` and is not logged.

Every proportion in the response is a fraction in 0..1: each metric
``value``, ``p_better``, ``p_equivalent``, and both lift intervals — where
0.25 means +25%, not +0.25%.

## Path parameters

- `experiment_id` string, required

## Response `200`

Successful Response

- object

## Other responses

- `400`: Invalid experiment ID format
- `403`: User may not edit this experiment's campaign
- `404`: No such experiment
- `422`: Validation Error

## Changes

- **2026-09-03** `219a10b80707`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/outrival/apis/fastapi/changes/api/v1/experiments/:experiment_id/readout/get.md)

---

[API](https://skmtc.dev/outrival/apis/fastapi.md) - [All operations](https://skmtc.dev/outrival/apis/fastapi/llms.txt) - [OpenAPI document](https://skmtc.dev/outrival/apis/fastapi/revisions/f27d90300b5e?raw)