gcanti/io-ts

Health v2 · maintenance only

Adoption not part of the score

6808 stars · 318 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

io-ts is a TypeScript library providing a runtime type system for decoding and encoding data at IO boundaries. Codecs combine static types with runtime validation, type guards, and encoding via fp-ts's Either type.

Use cases

• validate untrusted JSON against a TypeScript type at runtime
• decode API responses into typed values
• encode domain objects before sending them over the wire
• create custom type guards for unknown inputs
• define runtime-checked schemas shared between frontend and backend

When to choose

• you want static TypeScript types and runtime validation from a single definition
• your codebase already uses fp-ts and functional programming patterns
• you need precise, composable decoders with detailed error contexts

When to avoid

• you want a simple schema validator without functional programming concepts like Either and monads
• you prefer Zod-style ergonomic APIs with less boilerplate
• your project is plain JavaScript without TypeScript

Facets

library · maturity stable

serialization type-system form-handling developer-tools web-development apis cross-platform runtime-type-system codec decoder encoder fp-ts type-guards nodejs typescript

Member repositories

For agents

markdown · JSON · MCP: product_card(name="gcanti/io-ts")