Skip the protoc toolchain and get TypeScript types in seconds
Setting up protoc with a TypeScript plugin is worthwhile for a long-running project, but it is overhead you do not need when the goal is a single interface for a code review, a quick type check, or a proof-of-concept. This page lets you paste a .proto definition, pick the message, and copy a TypeScript interface without installing any toolchain or leaving the browser.
The generated interface maps protobuf scalars to their TypeScript equivalents — int32 and float become number, bool becomes boolean, bytes becomes Uint8Array, and nested messages become inline interfaces. Repeated fields are emitted as arrays, and optional fields include undefined in their type union so the interface reflects what the wire format can actually produce.
How protobuf types map to TypeScript
Protobuf's type system does not align one-to-one with TypeScript. The int32, uint32, sint32, float, and double types all collapse to number. The int64 and uint64 types map to string by default because JavaScript cannot represent 64-bit integers without precision loss. Enums become TypeScript enums when the schema names them, and oneof groups translate to a union type where only one branch is populated at a time.
Understanding these mappings matters when the generated interface will be used for runtime validation or serialization. If a field is bytes, the interface provides Uint8Array rather than string so downstream code that handles binary data does not need a secondary cast. If a field is a map, the interface emits a Record type that preserves the key and value types from the schema.
When to use generated types versus a full code-generation pipeline
A browser-based generator is ideal for ad-hoc work: reviewing a .proto file someone shared, adding a type to a test file, or creating a quick data transfer object for a prototype. It is not a replacement for a build-integrated pipeline in a production codebase that tracks schema revisions across teams. The practical rule is: if you need one interface right now, paste the schema here. If you need every interface updated on every commit, set up buf or protoc in CI.
The page still saves time even in pipeline-heavy workflows. When you are debugging a type mismatch between a generated client and a server contract, comparing the interface this tool produces against the one your pipeline emits can pinpoint whether the issue is in the schema, the plugin configuration, or the runtime serialization layer.