Contract-driven Socket.IO for TypeScript. Declare each event once — with its direction and its Zod schemas — and the client generates itself. Every frame is validated on the way out and on the way in, acknowledgements included.

Part of TypeWire ↗, so it shares typefetch's "module.event" identifier scheme and its instrument() seam: HTTP and WebSocket traffic land in one devtools timeline with no adapter glue.

Why direction belongs in the contract

v1 took two maps — onEvents and emitEvents — named from the client's point of view. That works for a client and only a client: a server gateway consuming the same object needs them swapped, so it had to declare a mirrored copy that could drift.

Tagging each event with direction makes the contract readable from both ends. The client emits client->server events and listens to server->client ones; a server adapter does exactly the reverse, from the same object. It also gives every event a stable eventId ("chat.sendMessage") — the same "module.endpoint" shape typefetch uses — so a cache or a devtools panel can key both transports the same way.

client.modules.chat.sendMessage.eventId; // "chat.sendMessage"
client.modules.chat.sendMessage.def;     // the contract definition
client.events;                           // every event, flattened, for tooling