# observablehq/runtime

The reactive dataflow runtime that powers Observable Notebooks

Repository: https://github.com/observablehq/runtime
Canonical: https://ross.abutalabs.com/products/observablehq-runtime
Homepage: https://observablehq.com
Language: JavaScript
License: ISC
License Family: permissive
Last push: 2026-07-04T20:45:21+00:00

## Health v2 (maintenance only)
Score: 63/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 90, release rhythm 8, longevity 100
- inputs: {"age_days": 3410, "days_push": 60, "days_rel": 665, "gap_med": null, "n_releases_24m": 1}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1086, forks 84 (observed 2026-08-28T04:03:31.961887+00:00)

## What it is
The Observable Runtime is a JavaScript library implementing reactive dataflow computation, powering Observable Notebooks. It lets you define variables with dependencies that automatically recompute when their inputs change, in the browser or Node.

## Use cases
- build reactive dataflow applications in javascript
- embed interactive observable notebook cells in my website
- run observable notebook code outside the platform
- create variables that automatically recompute when dependencies change
- build custom notebook-like reactive environments
- render live data visualizations that update reactively

## When to choose
- you want Observable Notebook-style reactive semantics in your own app or embed
- you need fine-grained dependency-driven recomputation of JavaScript variables
- you are building tooling on top of Observable notebooks or Framework

## When to avoid
- you just want to author notebooks on observablehq.com without custom embedding
- you need a general-purpose state management library for UI frameworks like React
- you want a static site generator - use Observable Framework instead

## Facets
- artifact type: library
- maturity: active
- function: state-management, data-visualization, developer-tools
- domain: data-visualization, data-science, web-development, developer-tools
- platform: browser
- tags: reactive-programming, dataflow, notebooks, observable, data-apps, javascript, nodejs

## Member repositories
- observablehq/runtime (main) score 63

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:31.961887+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 2026-08-30T06:49:36.833345+00:00, confidence not recorded.
  - readme: https://github.com/observablehq/runtime (fetched 2026-08-28T04:03:31.961887+00:00, sha 0169c54ae9db)
  - homepage: https://observablehq.com (fetched 2026-08-29T12:52:19.907464+00:00, sha 5d8cbd6e3393)
  - site_page: https://observablehq.com/documentation/notebooks (fetched 2026-08-29T12:52:19.918518+00:00, sha ebdd793e4361)
  - site_page: https://observablehq.com/documentation/embeds (fetched 2026-08-29T12:52:19.920595+00:00, sha 6ab173f717d1)
  - site_page: https://observablehq.com/documentation (fetched 2026-08-29T12:52:19.922434+00:00, sha 56816dd5b98c)
  - site_page: https://observablehq.com/about (fetched 2026-08-29T12:52:19.924006+00:00, sha d98710d59d60)
  - site_page: https://observablehq.com/pricing (fetched 2026-08-29T12:52:19.916711+00:00, sha 11c767c574af)
- Data as of 2026-08-30T08:39:29.467469+00:00.