Roadmap

6.0 is in development on the main branch. It isn't released yet, and it may still change. #320 tracks it, and Migration lists every change. 5.x keeps its current API, and gets bug and security fixes on the release/5.x branch.

6.0

These change behaviour or remove things, so they wait for a major version.

Done on main:

• No dependencies. Success, Error and the dispatch functions return small dataclasses of their own instead of oslash's Right and Left. A hand-written check of the request fields replaces jsonschema, and makes dispatching a small method about four times faster.
• Python 3.11 or later. 3.8, 3.9 and 3.10 have reached end of life.
• Safer defaults.
  • Batches hold at most 100 requests unless you set max_batch_size.
  • NaN, Infinity and numbers too big for a float in a request are a Parse error.
  • An Error with a non-integer code is a TypeError, and a method name starting with rpc. is a ValueError. 5.0.10 warned.
  • serve() listens on localhost unless you give it a host.
• max_concurrency limits how many requests of a batch async_dispatch runs at once.
• Cleanups. The names 5.0.10 deprecated are gone. The sync and async dispatch functions take the same options. One @method decorator serves sync and async functions.

Releases:

• 5.2.0, from release/5.x, warns where code depends on something 6.0 changes. Released 6 November 2026.
• 6.0.0rc1, the first release candidate, also 6 November 2026. pip install --pre jsonrpcserver installs it. 6.0.0 follows once it has had some use.

Ideas under discussion

• Middleware around method calls (#126). Decorators on your own functions already cover most uses.
• OpenRPC schema generation (#156), probably as a separate package.

5.1.0 took one idea from this list early: a method can return a plain value (#285).