---
title: "List Optimization Runs"
method: GET
path: "/optimizations/{id}/runs"
tags: ["optimizations"]
---

# List Optimization Runs

`GET /optimizations/{id}/runs`

## Request

- Base URL: `https://api.ionworks.com`
- URL: `https://api.ionworks.com/optimizations/{id}/runs`
- Auth: none declared

List the multistart runs of an optimization in one call.

Each run carries status and convergence history (read server-side),
so the frontend renders per-run progress without touching jobs.

## Path parameters

- `id` string, uuid, required

## Response `200`

Successful Response

- OptimizationRun[]
  - `run_id` string, required: Opaque identifier for this optimization run.
  - `index` integer, required: Zero-based position of the run, in creation order.
  - `status` 'queued' | 'running' | 'succeeded' | 'failed' | 'canceled', required: Frontend-facing lifecycle status for an async resource.
  - `element_key` string, nullable: For an array fit, the independent-variable value of the element this run belongs to, e.g. '25.0'. Null for a single fit and for runs recorded before the field existed.
  - `start_id` string, nullable: The run's multistart within its fit, from '0'. An array fit repeats it in every element, so pair it with element_key. Null for runs recorded before the field existed.
  - `intermediate_results` object[], nullable: Per-iteration convergence history for the run; its length is the current iteration count. Null until the run produces history.

## Other responses

- `422`: Validation Error

## Changes

- **2026-09-30** `ea3d377fec1a`: 1 breaking
  - for the `path` request parameter `id`, the format changed from no format to `uuid`
- **2026-09-26** `8ed5440390f0`: 2 info
  - added the optional property `items/element_key` to the response with the `200` status
  - added the optional property `items/start_id` to the response with the `200` status

[Operation history](https://skmtc.dev/ionworks/apis/ionworks-api/changes/optimizations/:id/runs/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)