# FormidableLabs/rapscallion

Asynchronous React VirtualDOM renderer for SSR.

Repository: https://github.com/FormidableLabs/rapscallion
Canonical: https://ross.abutalabs.com/products/rapscallion
Language: JavaScript
License: MIT
License Family: permissive
Topics: react, server-side-rendering, react-dom, asynchronous, stream, html, render
Archived: true
Last push: 2022-02-18T22:39:41+00:00

## Health v2 (maintenance only)
Score: 10/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 3499, "days_push": 1657, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, archived
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1387, forks 50 (observed 2026-08-28T04:04:35.209579+00:00)

## What it is
Rapscallion is an asynchronous React VirtualDOM renderer for server-side rendering. It offers streaming output, templating for HTML boilerplate, and component caching, and is roughly 30% faster than React's renderToString.

## Use cases
- render react components to html on the server asynchronously
- stream server-rendered html to the client as it renders
- speed up react ssr compared to renderToString
- wrap server-rendered react html in a page template while streaming
- cache rendered react component html for faster ssr

## When to choose
- you need non-blocking, streaming SSR for a React app on Node.js
- renderToString is too slow or blocks your server event loop
- you want template-based HTML wrapping integrated with streaming SSR

## When to avoid
- you use modern React 18+, which has built-in streaming SSR via renderToPipeableStream
- your project is not React-based
- you need a library with active development and recent updates

## Facets
- artifact type: library
- maturity: maintenance
- function: ssr, templating, caching, streaming
- domain: web-development, frontend, backend
- platform: -
- tags: react, server-side-rendering, virtual-dom, html-streaming, async-rendering, nodejs, javascript

## Member repositories
- FormidableLabs/rapscallion (main) score 10

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:35.209579+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 2026-08-30T04:39:48.362213+00:00, confidence not recorded.
  - readme: https://github.com/FormidableLabs/rapscallion (fetched 2026-08-28T04:04:35.209579+00:00, sha 8a97b1cdaf6a)
  - registry_npm: https://registry.npmjs.org/rapscallion (fetched 2026-08-29T11:55:27.069091+00:00, sha ea0993b182f2)
- Data as of 2026-08-30T08:39:29.467469+00:00.