Whistle website screenshot

Whistle

Whistle is a cross-platform HTTP, HTTPS, HTTP/2, WebSocket, and TCP debugging proxy built on Node.js. It enables developers to inspect, intercept, modify, and replay network traffic through a rule-based configuration system with a built-in web UI.

Whistle publishes 1 API on the APIs.io network. Tagged areas include Debugging Proxy, Proxy, Network Debugging, HTTP, and HTTPS.

The Whistle catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Whistle’s developer surface includes documentation, getting-started guide, GitHub presence, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub
38.0/100 thin ▬ flat Agent 3/100 human only Full breakdown ↓
scored 2026-08-05 · rubric v0.9.1
AccessFreemium
1 APIs
Debugging ProxyProxyNetwork DebuggingHTTPHTTPSWebSocketDeveloper Tools

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-08-05 · rubric v0.9.1
Composite quality — 38.0/100 · thin
Contract Quality 8.5 / 25
Developer Ergonomics 3.9 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 4.8 / 13
Governance 7.0 / 12
Discoverability 5.9 / 10
Agent readiness — 3/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 10
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/whistle: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 1

Individual APIs this provider publishes, each with its own machine-readable definition.

Whistle

Whistle is a cross-platform HTTP, HTTPS, HTTP/2, WebSocket, and TCP debugging proxy tool. It lets developers intercept, inspect, and modify network traffic using a rule-based co...

Pricing Plans 1

Published pricing tiers and plan structures.

Whistle Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Whistle Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Whistle Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Whistle Context

9 classes · 15 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Whistle API Rules

5 rules · 4 warnings 1 info

SPECTRAL

JSON Schema 2

Standalone JSON Schema definitions for this provider's data models.

Whistle Plugin

6 properties

JSON SCHEMA

Whistle Rule

4 properties

JSON SCHEMA

JSON Structure 1

JSON Structure definitions describing this provider's data shapes.

Whistle Rule Structure

3 properties

JSON STRUCTURE

Examples 1

Example request and response payloads for these APIs.

Whistle Rule Example

3 fields

EXAMPLE

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Whistle Domain Security

TLSv1.3

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

GettingStarted
GettingStarted

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Build 6

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization
 GitHub
GitHub
 NPM
NPM
 DesktopClient
DesktopClient
 ChromeExtension
ChromeExtension
 PluginScaffolding
PluginScaffolding

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Company 2

The organization behind the API

LinkedIn
LinkedIn
 Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: whistle
name: Whistle
description: Whistle is a cross-platform HTTP, HTTPS, HTTP/2, WebSocket, and TCP debugging proxy built on Node.js. It enables
  developers to inspect, intercept, modify, and replay network traffic through a rule-based configuration system with a built-in
  web UI.
type: Index
accessModel:
  pricing: freemium
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Freemium
  confidence: medium
  source:
  - plans
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/whistle.png
tags:
- Debugging Proxy
- Proxy
- Network Debugging
- HTTP
- HTTPS
- WebSocket
- Developer Tools
url: https://raw.githubusercontent.com/api-evangelist/whistle/refs/heads/main/apis.yml
created: '2026-03-27'
modified: '2026-05-03'
specificationVersion: '0.19'
apis:
- aid: whistle:whistle
  name: Whistle
  description: Whistle is a cross-platform HTTP, HTTPS, HTTP/2, WebSocket, and TCP debugging proxy tool. It lets developers
    intercept, inspect, and modify network traffic using a rule-based configuration system. Features include request/response
    modification, local file mapping, API mocking, remote debugging with Weinre, request replay via a built-in Composer, plugin
    support, and a web-based UI.
  humanURL: https://wproxy.org/whistle/
  baseURL: http://localhost:8899
  tags:
  - Debugging Proxy
  - Proxy
  - Network Debugging
  - HTTP
  - HTTPS
  - WebSocket
  - Developer Tools
  - API Mocking
  - Request Replay
  properties:
  - type: Documentation
    url: https://wproxy.org/en/docs/
  - type: GettingStarted
    url: https://wproxy.org/en/docs/getting-started.html
  - type: GitHub
    url: https://github.com/avwo/whistle
  - type: NPM
    url: https://www.npmjs.com/package/whistle
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/json-schema/whistle-rule-schema.json
  - type: JSONSchema
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/json-schema/whistle-plugin-schema.json
  - type: JSONStructure
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/json-structure/whistle-rule-structure.json
  - type: JSONLDContext
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/json-ld/whistle-context.jsonld
  - type: Examples
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/examples/whistle-rule-example.json
  - type: Vocabulary
    url: https://raw.githubusercontent.com/api-evangelist/whistle/main/vocabulary/whistle-vocabulary.yml
  contact:
  - FN: Whistle Team
    url: https://github.com/avwo/whistle
  features:
  - Request and response interception and modification
  - HTTP, HTTPS, HTTP/2, WebSocket, TCP support
  - Rule-based traffic modification
  - Local file mapping and API mocking
  - Built-in Weinre for remote DOM inspection
  - Request Composer for replay and editing
  - Plugin extensibility system
  - Multiple proxy modes: HTTP, HTTPS, Socks, reverse proxy
  - Cross-platform: macOS, Windows, Linux
  - Web-based management UI at localhost:8899
  use-cases:
  - Frontend development API proxying
  - Mobile app network debugging
  - CORS configuration testing
  - Request/response modification during development
  - API mocking with local JSON files
  - Remote debugging of web pages on devices
  - Traffic inspection and analysis
  integrations:
  - Chrome Extension ZeroOmega for proxy switching
  - Weinre for remote DOM inspection
  - Node.js NPM module integration
  - Desktop client via whistle-client
common:
- type: DomainSecurity
  url: security/whistle-domain-security.yml
- type: LinkedIn
  url: https://www.linkedin.com/company/whistle-labs
- type: Website
  url: https://wproxy.org/whistle/
- type: Documentation
  url: https://wproxy.org/en/docs/
- type: GettingStarted
  url: https://wproxy.org/en/docs/getting-started.html
- type: GitHubOrganization
  url: https://github.com/avwo
- type: GitHub
  url: https://github.com/avwo/whistle
- type: NPM
  url: https://www.npmjs.com/package/whistle
- type: DesktopClient
  url: https://github.com/avwo/whistle-client
- type: ChromeExtension
  url: https://github.com/avwo/whistle-for-chrome
- type: PluginScaffolding
  url: https://github.com/avwo/lack
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com