Preloop
Overview
Preloop is a Rust-based reimplementation of GitHub Actions designed to execute workflows locally or in self-hosted environments. It provides an isolated microVM runtime for each job, ensuring secure and reproducible execution. By leveraging Rust's performance and safety, Preloop aims to offer a faster and more reliable alternative to the standard GitHub Actions runner, particularly for developers who need to test workflows before pushing or who prefer self-hosted CI/CD solutions.
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Key Features
- Rust-based reimplementation of GitHub Actions
- Runs workflows locally or self-hosted
- Isolated microVM per job for security and reproducibility
- Compatible with existing GitHub Actions workflow syntax
- Open-source (likely, based on availability)
Pros
- Faster and more resource-efficient than the standard runner due to Rust
- Enhanced isolation with microVMs, improving security
- Allows local testing of workflows without pushing to GitHub
- Self-hosting flexibility for teams with specific infrastructure needs
Cons
- May lack some features or integrations of the official GitHub Actions runner
- Requires setup and maintenance for self-hosted environments
- Community and documentation may be limited compared to official tools
Who Is This Tool Best For?
Developers and teams seeking a local or self-hosted CI/CD runner that is compatible with GitHub Actions workflows and emphasizes isolation and performance.
Straight answers about Preloop
What is Preloop?
A reimplementation of GitHub Actions that runs workflows locally or on your own infrastructure, with each job isolated.
Is Preloop right for you?
Developers who want to test a workflow without pushing, or who have hit hosted CI limits on cost.
Is Preloop worth paying for?
It is free and open source, so there is no licence cost. What you provide is the machine to run it on.
What do you take on?
The runner. Hosted CI is somebody else’s patched machine; self-hosting means owning the images, the isolation and the upgrades, and that is the real cost of leaving.
Use cases
Testing a workflow before pushing
Running the pipeline locally turns a five-minute round trip into an immediate answer.
Keeping builds off hosted minutes
Self-hosting removes per-minute billing for repetitive jobs.
Running jobs in isolation
A microVM per job limits what a compromised dependency can reach.
Pricing
Preloop can be trialled at no cost, and we put it at 4.3. The project is free and open source, so the listing needs no price tier. The expense is the hardware and the time to keep it current. Details are on the project site. Treat the figures here as indicative and verify with the project site.
Alternatives
- Hosted CI runners — Nothing to maintain, and a bill that grows with usage.
- A self-hosted runner for the existing CI — The smaller step if you only want to move execution.
- A general container runner — More flexible, and entirely your problem to secure.
Every one of them is profiled in our AI tools directory.
What to confirm up front
Decide who patches it
A self-hosted runner is a machine with your code and secrets on it, and someone has to own the updates.
Check workflow compatibility
A reimplementation will not cover every action. Test your most complex workflow before moving the pipeline.