ESLint rule playground
Test custom ESLint rules in the browser
Paste a compact rule, define valid and invalid fixtures, then run a RuleTester-like check without sending code to a backend.
- Runtime
- Dedicated browser worker
- Compatibility
- RuleTester-like adapter
- TypeScript
- TypeScript syntax adapter
Checks messageId matching on Identifier nodes with one valid and one invalid JavaScript fixture.
Fixture JSON
Run result
No run yet
Choose a preset or edit the rule and fixtures, then run the tester.
Fixture workflow
Use one valid case, one invalid case and then expand toward TypeScript syntax, options and autofix boundaries.
Worker safety model
The tool blocks network and storage APIs, caps input size and terminates long runs; it is still for short synthetic examples, not untrusted packages.
TypeScript scope
The MVP parses TypeScript syntax with a TypeScript compiler syntax adapter. Type-aware projectService checks belong in repository CI or a server-side sandbox.