# ai/size-limit

Calculate the real cost to run your JS app or lib to keep good performance. Show error in pull request if the cost exceeds the limit.

Repository: https://github.com/ai/size-limit
Canonical: https://ross.abutalabs.com/products/size-limit
Language: JavaScript
License: MIT
License Family: permissive
Last push: 2026-07-30T12:45:50+00:00

## Health v2 (maintenance only)
Score: 92/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 95, release rhythm 83, longevity 100
- inputs: {"age_days": 3356, "days_push": 34, "days_rel": 34, "gap_med": 38, "n_releases_24m": 10}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6941, forks 1760 (observed 2026-08-28T04:09:51.633732+00:00)

## What it is
Size Limit is a performance budget tool for JavaScript that calculates the real cost (size and execution time) of your app or library and fails CI if it exceeds configured limits. It integrates with GitHub Actions and other CI systems to flag oversized dependencies in pull requests.

## Use cases
- keep my npm library bundle size under a limit
- fail CI when a pull request adds a heavy dependency
- measure how long a browser takes to download and execute my JS
- post bundle size changes as a comment on pull requests
- analyze why my bundle is large with --why
- set performance budgets for a JavaScript app

## When to choose
- you maintain a JS library or app and want to enforce bundle size or time budgets in CI
- you want PR feedback on bundle size changes
- you need tree-shaking-aware, dependency-inclusive size calculations

## When to avoid
- you need full runtime performance profiling rather than bundle cost estimation
- your project is not JavaScript-based
- you want visual bundle analysis only without budget enforcement

## Facets
- artifact type: cli-tool
- maturity: stable
- function: benchmarking, ci-cd, developer-tools, cli
- domain: developer-tools, performance, web-development, frontend
- platform: cli, cross-platform
- tags: performance-budget, bundle-size, javascript, ci, pull-request-checks, tree-shaking, nodejs

## Member repositories
- ai/size-limit (main) score 92

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:51.633732+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 2026-08-29T17:41:14.165125+00:00, confidence not recorded.
  - readme: https://github.com/ai/size-limit (fetched 2026-08-28T04:09:51.633732+00:00, sha 30504ec7de31)
  - registry_npm: https://registry.npmjs.org/size-limit (fetched 2026-08-29T08:37:15.456269+00:00, sha d0ea81660c25)
- Data as of 2026-08-30T08:39:29.467469+00:00.