Overview

jsoncurrent is a streaming JSON patch protocol for LLM responses. It solves the problem of delivering structured JSON to a client incrementally — as tokens arrive from the model — without waiting for a complete, parseable response.

How it works

The protocol has two components:

Emitter — runs on your server (Python or Node). Consumes raw LLM token output and emits StreamingChunk patch operations describing what changed. Plugs into your existing LLM stream.

Collector — runs on your client (JS/TS). Consumes patches and reconstructs the object incrementally. Emits change, pathstart, pathcomplete, and complete events as the object builds.


LLM tokens → [Emitter] → { path, value, op } patches → [Collector] → assembled object

Transport is yours to own. jsoncurrent has no opinion on SSE, WebSocket, or HTTP streaming — patches are plain JSON objects that you serialise and deserialise however your stack requires.

When to use it

jsoncurrent is the right tool when:

Your LLM backend is Python and you need to stream structured output to a JS client
Your server needs to participate in the stream — resolving placeholders, stripping fields, injecting database values — before the client sees anything
You want path-level lifecycle events (pathstart / pathcomplete) to drive progressive rendering without polling the full assembled state

Overview

How it works

When to use it

Next steps