---
title: "How Mastra got 6x faster GitHub Actions tests with StarSling"
description: "How Mastra made GitHub Actions tests 6x faster with StarSling's self-driving CI runners that optimize builds automatically."
url: https://starsling.dev/customers/mastra
---

`mastra-ai/mastra`

# How Mastra made their slowest test suite 6x faster and cut queue time by 8x with StarSling.

Mastra's slowest test suite dropped from 30 minutes to 5, and under load the wait for a runner fell from 15 minutes to under 2 minutes, all of it identified and shipped by StarSling agents.

> "At Mastra we move so fast that the bottleneck becomes reviews and CI. Time spent compounds, and StarSling helps you realize how much time you're losing."
>
> Abhi Aiyer

## By the numbers

- **5.87x** Faster Combined store Tests (29m 56s -> 5m 06s wall p95, post-migration)
- **8.2x** Shorter job queue (14m 48s -> 1m 48s job-queue p95, under load)

Series A - $35M raised - San Francisco

## Intro: 25K stars, 400+ contributors, and a test suite that grows every week

[Mastra](https://github.com/mastra-ai/mastra) is the most popular open-source TypeScript framework for building AI agents with **over 25,000 stars** on GitHub, **over 400 contributors**, new releases of packages going out daily with **600 to 700 PRs** merged every month. Mastra lets anyone building AI agents wire up memory, vector stores, RAG, evals, and more, which means there's tons of test surface area. A framework's whole job is to be fast for the developer building on it, so Mastra proves it on every PR: five test suites fanning out against a couple dozen vector and storage backends. Mastra built and tuned all of it themselves, but the matrix grows every time the framework does, so keeping it fast is a moving target, work that never actually finishes.

## Problem: A 30-minute test suite that grew with the framework

Mastra's slowest test suite, `Combined store Tests`, ran against 22 different vector and storage backends, and its slowest runs took 30 minutes. And on the busy days, part of that wasn't testing at all: with all 22 fanning out at once against a shared pool of GitHub-hosted runners, the ones at the back of the line waited about fifteen minutes for a runner before a single test could start. The suites had also collected the workarounds a fast-moving project accumulates: fixed `sleep` calls standing in for real readiness checks, services that raced the test runner on startup, a flaky ClickHouse race in the delete path. Mastra had built and tuned this matrix themselves, and each of these was real work to find and fix. But the suite grows every time the framework does, so the list never stopped getting longer, and that tax got paid more and more often.

> "On a busy day, a job could sit close to fifteen minutes in the queue before a single test even ran, and across the matrix that was real time gone every day. Now it's a minute or two."
>
> Abhi Aiyer

## Solution: CI that scoped and shipped its own optimizations

Mastra turned on self-driving CI on Feb 24, 2026, and let it run itself. Over the next **73 days** StarSling agents opened **fourteen PRs** on their own, no engineer triaged what to fix next. They replaced fixed-duration sleeps with polling across MongoDB, Chroma, and Couchbase. Added Docker healthchecks where services were racing the test runner. Sharded E2E kitchen-sink across three parallel jobs. Fixed the ClickHouse race. Migrated workflows to StarSling runners in batches as each round of optimizations made the next migration profitable. Mastra's engineers reviewed and merged each PR, but what to fix next was the agents' call.

> "Our test suite grows every week. It used to mean someone had to stop and make it fast again; now that just happens in the background while we keep shipping."
>
> Abhi Aiyer

## Results: 29m 56s -> 5m 06s

In the weeks after migration, once the runner swap and the agents' optimizations had landed, Combined store Tests measured **29m 56s -> 5m 06s** at the slow-tail p95, **5.87x faster**, with the other four suites pulled along behind it. Where the old shared pool left jobs queued about fifteen minutes at the p95 tail under load, StarSling held it to under two minutes, no matter how many contributors were pushing at once. And the bigger win is who stopped doing this work. The fixed `sleep` calls standing in for real readiness checks, the services racing the test runner on startup, the flaky ClickHouse race in the delete path, StarSling's agents found each one, opened the PR, and handed Mastra's engineers a clean diff to review and merge. The never-ending tuning of a suite that grows with the framework became work that handles itself.

> "Our team is really loving StarSling. The runners are just handled, so nobody on my team thinks about CI infrastructure anymore, and the agents keep optimizing for the one thing I care about, minutes saved."
>
> Abhi Aiyer

## When each speedup landed

Migration on 2026-02-24. Every entry is a merged `starsling/*` PR.

- 2026-02-24 [#13466](https://github.com/mastra-ai/mastra/pull/13466) Migrate Combined store Tests to StarSling Runners _(migration)_
- 2026-02-28 [#13607](https://github.com/mastra-ai/mastra/pull/13607) Migrate workflows to StarSling runners
- 2026-02-28 [#13610](https://github.com/mastra-ai/mastra/pull/13610) test(mongodb): optimize vector test suite by replacing fixed sleeps with polling
- 2026-03-05 [#13808](https://github.com/mastra-ai/mastra/pull/13808) test(mongodb): replace fixed sleeps with polling
- 2026-03-06 [#13937](https://github.com/mastra-ai/mastra/pull/13937) perf(memory): limit vitest parallelism to prevent OOM kills on CI
- 2026-03-07 [#13866](https://github.com/mastra-ai/mastra/pull/13866) test(chroma): reduce fixed 2000ms waitForIndexing sleep to 200ms and add Docker healthcheck
- 2026-03-07 [#13965](https://github.com/mastra-ai/mastra/pull/13965) test(couchbase): optimize vector test suite by replacing fixed sleeps with bucket.ping() and reducing wait times
- 2026-04-13 [#14098](https://github.com/mastra-ai/mastra/pull/14098) chore(ci): add timeout-minutes to all StarSling-hosted workflow jobs
- 2026-04-28 [#14520](https://github.com/mastra-ai/mastra/pull/14520) test(mssql): replace TCP healthcheck with sqlcmd, simplify pretest, pin Docker image
- 2026-04-29 [#15888](https://github.com/mastra-ai/mastra/pull/15888) ci: shard E2E kitchen-sink across 3 parallel jobs
- 2026-04-29 [#15895](https://github.com/mastra-ai/mastra/pull/15895) fix(clickhouse): make deleteTask/deleteTasks await mutation completion
- 2026-04-29 [#14044](https://github.com/mastra-ai/mastra/pull/14044) test(clickhouse): stop merges before TRUNCATE, use tmpfs and Docker healthcheck
- 2026-04-30 [#16015](https://github.com/mastra-ai/mastra/pull/16015) ci: migrate slow workflows to StarSling Runners
- 2026-05-08 [#16330](https://github.com/mastra-ai/mastra/pull/16330) ci(e2e): migrate remaining matrix jobs to starsling-ubuntu-24.04

## Where the time went

Measured at p95 wall-clock across all branches. Pre-migration: GitHub-hosted runners. Post: StarSling runners.

| Workflow | Before | After | Speedup |
|---|---:|---:|---:|
| Combined store Tests (vector+storage) | 29m 56s | 5m 06s | **5.87x** |
| Workspace Cloud Tests | 8m 44s | 2m 22s | **3.69x** |
| Memory Tests | 12m 11s | 6m 16s | **1.94x** |
| E2E Tests | 14m 16s | 10m 50s | **1.32x** |

## Methodology

Wall-clock p95 of the Combined store Tests workflow, across all branches. Before: GitHub-hosted runners, a 3-day window before migration. After: StarSling runners with the agents' optimizations merged, April 1 to 4.

Job queue: p95 of each job's wait for a runner (job.started_at - run.created_at) across the Combined store Tests matrix jobs, success jobs only, over the same windows as above.