reactor/reactor-core
Non-Blocking Reactive Foundation for the JVM observed · 2026-08-28
Health v2 · maintenance only
99/100
- Activity 99
- Release rhythm 99
- Longevity 100
How is this computed?
round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-03. Adoption (stars, forks) is never an input.
- gap_med: 27
- age_days: 3949
- days_rel: 10
- days_push: 7
- n_releases_24m: 36
Adoption not part of the score
5234 stars · 1254 forks observed · 2026-08-28
What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded
Reactor Core is a non-blocking reactive streams foundation library for the JVM, implementing a Reactive Extensions-inspired API with the Flux (0..N) and Mono (0..1) publisher types. It provides efficient demand management, backpressure, and high-throughput event streaming, and underpins frameworks like Spring WebFlux.
Use cases
- build non-blocking asynchronous applications on the JVM
- handle backpressure in high-throughput event streams
- compose asynchronous data pipelines with Flux and Mono
- implement reactive microservices with Spring WebFlux
- process millions of messages per second with low memory footprint
- debug reactive code with the reactor-tools java agent
When to choose
- you need a Reactive Streams implementation with rich operator support on the JVM
- you are building Spring Boot/WebFlux or RSocket/R2DBC-based reactive applications
- you need backpressure-ready, non-blocking concurrency without writing raw Reactive Streams
- you want a mature, well-documented library with testing utilities (reactor-test)
When to avoid
- you want simple synchronous code and don't need non-blocking concurrency
- you target Android officially (Reactor doesn't officially support it)
- your team is unfamiliar with reactive programming and the learning cost outweighs benefits
- you need a full framework rather than a foundation library
Facets
library · maturity stable
concurrency streaming middleware backend developer-tools microservices jvm cross-platform reactive-streams flux mono reactive-extensions backpressure non-blocking asynchronous spring-webflux java real-time
7 sources
- readme: https://github.com/reactor/reactor-core · fetched 2026-08-28 · c99d29db6e34
- homepage: http://projectreactor.io · fetched 2026-08-29 · dfddcb293632
- site_page: https://projectreactor.io/docs · fetched 2026-08-29 · 482fda30829b
- site_page: https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Flux.html · fetched 2026-08-29 · 10fd5a2fb999
- site_page: https://projectreactor.io/docs/core/release/api/reactor/core/publisher/Mono.html · fetched 2026-08-29 · 75a6cfb770f2
- site_page: https://projectreactor.io/docs/core · fetched 2026-08-29 · 41782e9b9167
- site_page: https://projectreactor.io/docs/netty · fetched 2026-08-29 · 1b61684940bb
Member repositories
| Repository | Role | Health v2 |
|---|---|---|
| reactor/reactor-core | main | 99 |
For agents
markdown · JSON · MCP: product_card(name="reactor/reactor-core")
Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem