GitHub Actions runner performance and cost optimization

Vitest isolate: when turning it off speeds up CI and when it breaks your tests

Disabling Vitest isolate can cut your test suite time in half — or surface a dozen flaky tests you never knew you had. Here's the tradeoff, spelled out.

Jest JUnit output: how to make Jest results readable in CI

Jest prints beautiful output in your terminal and useless output in CI. Here's how to emit JUnit XML that your pipeline can actually parse — and what to watch for.

Stop paying for cold caches: GitHub Actions runner cache benchmarks

The cache/save step looks free in your logs. It isn't. Real numbers on GitHub Actions cache restore times, layer reuse, and when self-hosted runners cut them to zero.

The Vitest cache, explained: what it stores, when to keep it, and when it lies to you

Vitest has two caches, and most teams cache the wrong one in CI. Here's what each does, how to configure them, and how one of them can make your test order nondeterministic.

Vitest performance: why your test suite is slow and how to fix it

Vitest is fast by default, but default isn't always fast enough. Here's how to actually diagnose and fix a slow Vitest suite.

docker/setup-buildx-action@v3: what it does, why it matters, and how to use it right

docker/setup-buildx-action@v3 is two lines of YAML that unlock multi-platform builds, layer caching, and faster CI — if you configure it correctly.

jest-junit: generate JUnit XML reports from Jest and surface them in CI

jest-junit transforms Jest's output into JUnit XML — the format every CI platform and test analytics tool understands. Here's how to configure it correctly.

How to speed up pytest

Runners: Slow test suites aren’t just annoying; they can grind your team’s momentum to a halt, delay releases, and make everyone grumpy.

How to speed Up Vitest

Runners: There are always room to squeeze out more performance.

How to speed up Playwright tests

Runners: We’ve seen a few tricks to help frontend teams and distilled findings down to a few concrete strategies without sacrificing coverage or reliability.

Non-obvious ways self-hosting GitHub Actions can increase CI cost.

Runners: With great power comes with great responsibility — it's not all sunshine and rainbows, there are some unobvious challenges.

BuildPulse Runners: Run your GitHub Actions 2x faster, at half the cost.

Runners: Run GitHub Actions builds on our optimized-infrastructure, geared to cut build times and cost.