---
title: "Earliest free start time on a channel"
method: GET
path: "/projects/{project_id}/planned_measurements/next_available"
tags: ["Planned Measurements"]
---

# Earliest free start time on a channel

`GET /projects/{project_id}/planned_measurements/next_available`

## Request

- Base URL: `https://api.ionworks.com`
- URL: `https://api.ionworks.com/projects/{project_id}/planned_measurements/next_available`
- Auth: none declared

Return the earliest start time a channel is free for ``duration_seconds``.

``next_available_start`` is ``null`` when the channel is occupied by a
running measurement with no known end time.

## Path parameters

- `project_id` string, uuid, required

## Query parameters

- `channel_id` string, uuid, required
- `duration_seconds` integer, required

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

## Changes

- **2026-09-30** `ea3d377fec1a`: 2 breaking
  - for the `path` request parameter `project_id`, the format changed from no format to `uuid`
  - for the `query` request parameter `channel_id`, the format changed from no format to `uuid`

[Operation history](https://skmtc.dev/ionworks/apis/ionworks-api/changes/projects/:project_id/planned_measurements/next_available/get.md)

---

[API](https://skmtc.dev/ionworks/apis/ionworks-api.md) - [All operations](https://skmtc.dev/ionworks/apis/ionworks-api/llms.txt) - [OpenAPI document](https://skmtc.dev/ionworks/apis/ionworks-api/revisions/abebbbc5f60a?raw)