⌁runtimereadySTATIC COMPATIBILITY INTELLIGENCE
SAVED COMPATIBILITY REPORT

socket.io@4.8.4
on Cloudflare Workers

Analyzed · Static analysis only

A saved snapshot, not a live compatibility guarantee. Opening this page does not run a scan.

Analyze a package ↗Methodology and limitations

What compatibility issues were found on Cloudflare Workers?

The saved analysis assesses socket.io@4.8.4 as potential issue for Cloudflare Workers. Review the findings and coverage below; this is not a runtime execution test.

Potential issue

83/100 · medium confidence

No detected blocker within scan limits does not mean verified execution. Scores are heuristics, not probabilities.

import
Potential issue
execute
Likely compatible
APIs
Potential issue
SSR
Likely compatible

21 packages and 96 files scanned. Coverage describes the inspected scope, not every possible code path.

FILE AND DEPENDENCY EVIDENCE

18 findings to review

1. Filesystem API

Potential issue

Imports fs

Source excerpt

dist/index.js:41:14 · first detected occurrence

exports.Namespace = exports.Socket = exports.Server = void 0;
const http_1 = require("http"); // 'node:' prefix was added in Node.js 16
const fs_1 = require("fs");
const zlib_1 = require("zlib");
const accepts = require("accepts");

Suggested next steps

Check the storage operation and execution environment
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Identify which filesystem operation is used and whether your target runtime implements that operation with the required persistence and permissions.
  3. If it is needed but unsupported, move filesystem work to a supported server environment or adapt it to the runtime's storage APIs. A shim cannot supply a real filesystem.
  4. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
dist/index.js
Dependency path
socket.io@4.8.4
Entry points
wrapper.mjs
Dimension
apis
Reachability
not proven reachable from selected entry
Confidence
low · static

2. Filesystem API

Potential issue

Imports fs

Source excerpt

dist/uws.js:10:14 · first detected occurrence

exports.serveFile = serveFile;
const socket_io_adapter_1 = require("socket.io-adapter");
const fs_1 = require("fs");
const debug_1 = __importDefault(require("debug"));
const debug = (0, debug_1.default)("socket.io:adapter-uws");

Suggested next steps

Check the storage operation and execution environment
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Identify which filesystem operation is used and whether your target runtime implements that operation with the required persistence and permissions.
  3. If it is needed but unsupported, move filesystem work to a supported server environment or adapt it to the runtime's storage APIs. A shim cannot supply a real filesystem.
  4. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
dist/uws.js
Dependency path
socket.io@4.8.4
Entry points
wrapper.mjs
Dimension
apis
Reachability
not proven reachable from selected entry
Confidence
low · static

3. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
lib/index.js
Dependency path
socket.io@4.8.4 → cors@2.8.6
Entry points
lib/index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

4. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
src/index.js
Dependency path
socket.io@4.8.4 → debug@4.4.3
Entry points
src/index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

5. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → accepts@1.3.8
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

6. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
dist/index.js
Dependency path
socket.io@4.8.4 → socket.io-adapter@2.5.8
Entry points
dist/index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

7. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → cors@2.8.6 → object-assign@4.1.1
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

8. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → cors@2.8.6 → vary@1.1.2
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

9. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index
Dependency path
socket.io@4.8.4 → debug@4.4.3 → ms@2.1.3
Entry points
index
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

10. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → accepts@1.3.8 → mime-types@2.1.35
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

11. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → accepts@1.3.8 → negotiator@0.6.3
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

12. Node built-in

Potential issue

Imports net

Source excerpt

lib/websocket.js:8:13 · first detected occurrence

const https = require('https');
const http = require('http');
const net = require('net');
const tls = require('tls');
const { randomBytes, createHash } = require('crypto');

Suggested next steps

Verify the exact Node API being used
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Inspect which methods are called, then compare those methods with the target runtime's API support. An import that resolves may still expose unsupported methods.
  3. If required methods are unavailable, choose an exported runtime-specific entry, replace the operation with supported APIs, or run that part of the application in a supported Node environment.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
lib/websocket.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → ws@8.21.3
Entry points
browser.js
Dimension
apis
Reachability
not proven reachable from selected entry
Confidence
low · static

13. Node built-in

Potential issue

Imports tls

Source excerpt

lib/websocket.js:9:13 · first detected occurrence

const http = require('http');
const net = require('net');
const tls = require('tls');
const { randomBytes, createHash } = require('crypto');
const { Duplex, Readable } = require('stream');

Suggested next steps

Verify the exact Node API being used
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Inspect which methods are called, then compare those methods with the target runtime's API support. An import that resolves may still expose unsupported methods.
  3. If required methods are unavailable, choose an exported runtime-specific entry, replace the operation with supported APIs, or run that part of the application in a supported Node environment.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
lib/websocket.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → ws@8.21.3
Entry points
browser.js
Dimension
apis
Reachability
not proven reachable from selected entry
Confidence
low · static

14. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → cookie@0.7.2
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

15. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → @types/cors@2.8.19
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

16. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → @types/node@26.6.3
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

17. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → accepts@1.3.8 → mime-types@2.1.35 → mime-db@1.52.0
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

18. CommonJS entry

Potential issue

Selected entry appears to use CommonJS; this runtime may need bundler interop

Source excerpt

No source excerpt was saved for this finding. Older reports, manifest or binary signals, and inspection failures may not have a source location.

Suggested next steps

Review the package's module entry points
  1. First trace whether this file is reachable from the entry point your application uses. The finding may be outside the executed code path.
  2. Check the package's documented exports for a supported ESM or browser entry. Import public exported paths rather than guessing internal file paths.
  3. If only CommonJS is available, test your build tool's CommonJS conversion and interop behavior. Changing your own package to type: module does not convert a dependency's CommonJS source.
  4. This finding is in a transitive dependency. Prefer upgrading/configuring its parent package or proposing an upstream fix over editing installed node_modules.
  5. Check your Workers compatibility date and Node API support before making changes. This analyzer uses a coarse profile and does not model every compatibility flag or API implementation.

Rebuild and exercise the affected import and operation in your exact runtime, version, and deployment configuration. These suggestions are not a tested fix.

File
index.js
Dependency path
socket.io@4.8.4 → engine.io@6.6.11 → @types/node@26.6.3 → undici-types@8.9.0
Entry points
index.js
Dimension
import
Reachability
not proven reachable from selected entry
Confidence
low · static

How to use this report

This report preserves the findings as of September 29, 2026 at 6:19 PM UTC. It may use older analysis rules (analysis version 3). Package code was not executed. Runtime versions, flags, bundlers, and operating systems can change actual compatibility.

Reachability is approximate. Optional dependencies, generated code, dynamic imports, and incomplete scans can cause false positives or missed issues. A green assessment means no blocker was found within the inspected scope. The score is a heuristic, not a probability.

Read all limitations ↗