Ross ROSS = Recommend OSS · open-source software intelligence for agents

tumblr/colossus

I/O and Microservice library for Scala observed · 2026-08-28

github.com/tumblr/colossus · Scala · Apache-2.0 (permissive) observed · 2026-08-28

Health v2 · maintenance only

23/100

  • Activity 0
  • Release rhythm 8
  • Longevity 100
How is this computed?

round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10) — computed 2026-09-02. Adoption (stars, forks) is never an input.

  • gap_med: n/a
  • age_days: 4313
  • days_rel: n/a
  • days_push: 1845
  • n_releases_24m: 0

Full methodology

Adoption not part of the score

1129 stars · 95 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Colossus is a lightweight I/O framework for building high-performance Scala microservices, including an HTTP server/client and a standalone metrics library. It was developed by Tumblr and participates in the TechEmpower web framework benchmarks.

Use cases

  • build a scala microservice
  • high-performance http server in scala
  • non-blocking i/o service framework for jvm
  • collect and report service metrics
  • write scala http clients

When to choose

  • you are building Scala services on the JVM and want a lightweight, non-blocking I/O framework
  • you need a simple HTTP server/client with built-in metrics support

When to avoid

  • your team primarily uses Java, Kotlin, or another non-Scala JVM language
  • you need a framework with a large ecosystem and frequent updates, as the latest release dates to 2021

Facets

framework · maturity maintenance

http-server http-client microservices monitoring serialization testing backend microservices web-development developer-tools jvm scala nio high-performance service-framework metrics linux macos

1 source

Member repositories

RepositoryRoleHealth v2
tumblr/colossusmain23

For agents

markdown · JSON · MCP: product_card(name="tumblr/colossus")

Data as of 2026-08-30T08:39:29.467469+00:00 · Report a problem