---
title: "Get experiment trends"
method: GET
path: "/api/experiments/{experimentId}/trends"
tags: ["experiments"]
---

# Get experiment trends

`GET /api/experiments/{experimentId}/trends`

## Request

- Base URL: `https://api.iterable.com`
- URL: `https://api.iterable.com/api/experiments/{experimentId}/trends`
- Auth: API key in header `Api-Key`

Get histogram time series data for each variant in a campaign experiment. Iterable picks the interval between data points based on the date range. To choose a date range, send both <code>startDateTime</code> and <code>endDateTime</code> as UTC ISO 8601 timestamps. The range must fall within the period the experiment ran and can't exceed 31 days. If you omit both, Iterable returns up to the last 31 days the experiment ran, ending one minute before the experiment ended, or before the current time if it's still <code>running</code>. If the experiment hasn't started, the response contains no data. This endpoint doesn't support journey experiments.

## Path parameters

- `experimentId` integer, required

## Query parameters

- `startDateTime` string, date-time
- `endDateTime` string, date-time

## Response `200`

successful operation

- ExperimentTrendsResponse: Histogram time series for a campaign experiment
  - `endDateTime` string, date-time, required: Inclusive series end in UTC ISO-8601
  - `holdout` ExperimentTrendsVariant: Time series for one experiment variant or holdout
    - `id` integer, required: Variant sequence ID, or <code>-1</code> for holdout
    - `isControl` boolean, required: Whether this variant is the control
    - `isWinner` boolean, required: Whether this variant is the winner
    - `name` string, required: Variant name
    - `series` object, required: Time series for each metric, keyed by metric name, such as <code>TotalEmailSend</code>
  - `id` integer, required: Experiment ID
  - `interval` string, required: Auto-selected histogram interval label
  - `startDateTime` string, date-time, required: Inclusive series start in UTC ISO-8601
  - `status` 'draft' | 'ready' | 'running' | 'finished' | 'winner_found', required: Experiment status
  - `variants` ExperimentTrendsVariant[], required: Time series for each variant, not including the holdout group
    - `id` integer, required: Variant sequence ID, or <code>-1</code> for holdout
    - `isControl` boolean, required: Whether this variant is the control
    - `isWinner` boolean, required: Whether this variant is the winner
    - `name` string, required: Variant name
    - `series` object, required: Time series for each metric, keyed by metric name, such as <code>TotalEmailSend</code>

## Other responses

- `400`: Invalid parameters
- `401`: Invalid API key
- `404`: Experiment or campaign not found

## Changes

- **2026-09-30** `cca837e62715`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/iterable/apis/iterable-api/changes/api/experiments/:experimentId/trends/get.md)

---

[API](https://skmtc.dev/iterable/apis/iterable-api.md) - [All operations](https://skmtc.dev/iterable/apis/iterable-api/llms.txt) - [OpenAPI document](https://skmtc.dev/iterable/apis/iterable-api/revisions/a430ac1d1db7?raw)