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aidenybai/tla-ts

A TypeScript implementation of the TLA+ interpreter and model checker, a drop-in replacement for the Java-based TLC that runs in browsers, Node, and Bun.

Open-source alternative to:TLC

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232
Forks
9
Open issues
9
Last commit
2 days ago

What is it?

tla-ts is a TLA+ interpreter and model checker written in TypeScript. It is meant as a drop-in replacement for TLC, the reference model checker for TLA+ specifications, which is written in Java and requires the JVM. Because tla-ts runs wherever JavaScript runs, including the browser, Node, and Bun, formal models can be checked without a Java installation.

The project also checks TLAPS proofs, so proof obligations can be verified without installing tlapm. It exposes a JavaScript API with `check`, `prove`, `parseModule`, and `parseConfig`, plus a command line that accepts TLC's options and a tlapm-style interface. Errors are reported through typed classes for syntax, configuration, evaluation, and unsupported constructs.

The repository reports benchmarks against TLC, with speedups of roughly 1.1× to 2.4× depending on the spec and worker count. It includes a browser playground and a conformance suite compared against TLC's recorded results.

Key features

  • 01Runs TLA+ model checking in browsers, Node, and Bun without the JVM.
  • 02Checks TLAPS proof obligations without installing tlapm.
  • 03Provides `check`, `prove`, and parser functions in a JavaScript API.
  • 04Ships a command line that accepts TLC options and tlapm-style commands.
  • 05Supports multiple worker threads for parallel state exploration.

Use cases

  • Model checking distributed protocol specs from a Node or browser environment.
  • Running TLA+ checks in a JavaScript-based CI pipeline without a Java setup.
  • Sharing an interactive TLA+ playground in the browser for teaching or demos.
  • Checking TLAPS proofs in projects that already use a Node toolchain.

Quick start

  1. 1

    Install the package from npm

    npm install tla-ts
  2. 2

    Check a TLA+ spec from the command line

    npx tla-ts Spec.tla

Things to know

  • Early-stage project with a relatively small community (191 stars).

Topics

#formal-verification#tlaplus#typescript#model-checking#theorem-proving#javascript

FAQ

What is tla-ts?
A TypeScript implementation of the TLA+ interpreter and model checker, a drop-in replacement for the Java-based TLC that runs in browsers, Node, and Bun. tla-ts is a TLA+ interpreter and model checker written in TypeScript. It is meant as a drop-in replacement for TLC, the reference model checker for TLA+ specifications, which is written in Java and requires the JVM. Because tla-ts runs wherever JavaScript runs, including the browser, Node, and Bun, formal models can be checked without a Java installation.
Is tla-ts free to use? What license does it have?
tla-ts is open source under the MIT license. Check the license terms before using it in commercial products.
Is tla-ts still maintained?
Actively maintained. The last commit to tla-ts was on Nov 5, 2026.
What can I use tla-ts for?
Model checking distributed protocol specs from a Node or browser environment. Running TLA+ checks in a JavaScript-based CI pipeline without a Java setup. Sharing an interactive TLA+ playground in the browser for teaching or demos. Checking TLAPS proofs in projects that already use a Node toolchain.
How do I install tla-ts?
Install the package from npm: npm install tla-ts Check a TLA+ spec from the command line: npx tla-ts Spec.tla
Where can I get tla-ts?
The source code and installation instructions are on GitHub: https://github.com/aidenybai/tla-ts

Summary generated by AI from the project's README. GitHub stats refresh daily.

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