Convex Pro Max

The definitive guide for building production-ready Convex applications.

Critical Rules

1. Always use new function syntax with args, returns, and handler.
2. Always validate args AND returns on public functions.
3. Always use indexes — never .filter() on the database. Use .withIndex().
4. Always await promises — enable @typescript-eslint/no-floating-promises.
5. Use internal* functions for scheduled jobs, crons, and sensitive operations.
6. Never use ctx.db in actions — use ctx.runQuery/ctx.runMutation.
7. Actions are NOT transactional — consolidate reads into single queries, writes into single mutations.
8. Return null explicitly if a function returns nothing (returns: v.null()).
9. Use v.id("table") not v.string() for document IDs.
10. Install @convex-dev/eslint-plugin — enforces object syntax, arg validators, explicit table IDs, correct runtime imports.

Function Types