CompatLab

npx add-mcp 'https://compatlab.me/mcp'

CompatLab

Check whether an npm package loads with import and require in Node.js, Bun and Deno.

Published npm packages are tested on Linux amd64 / glibc with pinned runtime images. Install scripts stay disabled. Loading success does not establish functional correctness or package safety.

Search by name at https://compatlab.me/ or read the public API guide. Reads never start scans.

Browse npm compatibility results · Observed runtime loading failures

Completed reports

• preact 11.0.0: Inconclusive; planned coverage complete.

• express 5.3.0: Passed; planned coverage complete.

• zod 4.6.7: Inconclusive; coverage limited.

Example runtime results

node 24.21.0

Profile: node_24_21_0. Image: sha256:ae61554e1d39b7a8aaa8ed25f3bf8dc883176e544d0c7b9b461618ad0930cd6d.

• root esm: Passed; 1 passed · 0 failed.

• root commonjs: Passed; 1 passed · 0 failed.

• subpaths esm: Inconclusive; 12 passed · 2 need optional peers.

• subpaths commonjs: Inconclusive; 12 passed · 2 need optional peers.

node 26.10.0

Profile: node_26_10_0. Image: sha256:c26032c5da3d5f0b93e391591be439a6ed5d9cdf47fc854b7d715c50794c0c6e.

• root esm: Passed; 1 passed · 0 failed.

• root commonjs: Passed; 1 passed · 0 failed.

• subpaths esm: Inconclusive; 12 passed · 2 need optional peers.

• subpaths commonjs: Inconclusive; 12 passed · 2 need optional peers.

bun 1.4.2

Profile: bun_1_4_2. Image: sha256:661406fb7c65de07544f88300466de4b5f52dff7aa4866ca4114377d6825bb11.

• root esm: Passed; 1 passed · 0 failed.

• root commonjs: Passed; 1 passed · 0 failed.

• subpaths esm: Inconclusive; 12 passed · 1 failed · 1 batch failure unconfirmed.

• subpaths commonjs: Inconclusive; 12 passed · 1 needs an optional peer · 1 batch failure unconfirmed.

deno 2.9.7

Profile: deno_2_9_7. Image: sha256:e38d0b2ed731e26a252e1c17f60960916d1efc1d1dc4d43a5ca6667818248b66.

• root esm: Passed; 1 passed · 0 failed.

• root commonjs: Passed; 1 passed · 0 failed.

• subpaths esm: Inconclusive; 12 passed · 2 need optional peers.

• subpaths commonjs: Inconclusive; 12 passed · 2 need optional peers.

From the lab

Check npm compatibility with MCP: a guide for AI agents

Connect Claude Code, Cursor or Codex to CompatLab's MCP server. Check npm packages across Node.js, Bun and Deno, interpret real reports and cite evidence.

Do npm packages work on Node.js, Bun and Deno? We built a tool to find out

Real npm package compatibility results for Express, Preact, Zod and the Convex agent across Node.js, Bun and Deno, with failures, coverage and linked evidence.

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