# unum-cloud/UCall

Web Serving and Remote Procedure Calls at 50x lower latency and 70x higher bandwidth than FastAPI, implementing JSON-RPC & REST over io_uring ☎️

Repository: https://github.com/unum-cloud/UCall
Canonical: https://ross.abutalabs.com/products/ucall
Homepage: https://unum-cloud.github.io/UCall/
Language: C
License: Apache-2.0
License Family: permissive
Topics: cpython, epoll, fast-api, flask, io-uring, json, json-rpc, liburing, python, http, http-server, tcp, tcp-ip, linux-kernel, rpc, rpc-framework, simd, backend, dpdk, rest-api
Last push: 2025-09-16T13:07:15+00:00

## Health v2 (maintenance only)
Score: 46/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 42, release rhythm 24, longevity 95
- inputs: {"age_days": 1338, "days_push": 351, "days_rel": 351, "gap_med": 172.5, "n_releases_24m": 3}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1331, forks 54 (observed 2026-08-28T04:04:24.390374+00:00)

## What it is
UCall is a high-performance JSON-RPC and REST serving library written in C with Python bindings, using io_uring and POSIX sockets to achieve far lower latency than FastAPI or gRPC. It exposes a FastAPI-like decorator API for defining remote procedures served over TCP/HTTP.

## Use cases
- serve -rpc endpoints with minimal latency
- replace fastapi for high-throughput microservices
- build low-latency rpc backend in python
- expose python functions over rest or -rpc
- benchmark web serving frameworks
- handle thousands of requests per second on linux

## When to choose
- you need much lower latency or higher throughput than FastAPI or gRPC
- you run on modern Linux kernels with io_uring support
- you want a simple decorator-based API for RPC services

## When to avoid
- you need full REST ecosystem features like middleware, auth, or OpenAPI generation
- you deploy on non-Linux platforms without io_uring
- you need a mature framework with a large community and plugins

## Facets
- artifact type: library
- maturity: active
- function: rpc, http-server, web-framework, serialization
- domain: backend, web-development, apis, performance, developer-tools
- platform: python, c, cli
- tags: -rpc, io-uring, fastapi-alternative, high-performance, rest, tcp, simd, linux

## Member repositories
- unum-cloud/UCall (main) score 46

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:24.390374+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:45:21.679713+00:00, confidence not recorded.
  - readme: https://github.com/unum-cloud/UCall (fetched 2026-08-28T04:04:24.390374+00:00, sha 0f6d0a6379b4)
  - homepage: https://unum-cloud.github.io/UCall/ (fetched 2026-08-29T12:04:24.235327+00:00, sha 69ac1c1f0e3f)
- Data as of 2026-08-30T08:39:29.467469+00:00.