GritQL lets any code snippet be a query for rewriting huge multi-language codebases

GritQL grew out of Grit's own large-scale refactors, where migrations follow a familiar arc: exploratory grep searches to scope the problem, then accumulated requirements — imports to ensure, edge cases to exclude — that push the work into a full codemod program. That jump is where most of the pain sat: the exploratory work gets abandoned, regex must be mentally translated into AST nodes, and every framework is language-specific and poorly composable.

GritQL's move was to let the query read like the code itself. Any code snippet in backticks is a valid query — `console.log($_)` finds every console.log call — with $metavariables as holes, `=>` turning a match into a rewrite, and where clauses adding side conditions such as 'not inside a try-catch'. The same grammar works for search, custom lints and migrations, so a first grep can harden into a permanent rule without switching tools or languages.

Written in Rust on tree-sitter, the engine scaled to 10M+ line repositories and a dozen target languages, and a module system plus a 200+ pattern standard library made complex migrations composable from small, reviewable rules. The Show HN of March 2024 brought 280 points and 54 comments, and commenters reported using it for real moves within days; by 2026 the project page lived under biomejs with 4.6k stars.