API Clients
Grouped by Kin Score band and ranked by composite score within each, with the separate agent-readiness score alongside. Click the scores on any row to open the full facet and dimension breakdown behind both numbers, and click again to close it.
search
34 providers
Exemplar 1 66.5+ Reference-quality API operations across every facet.
1
Postman Exemplar agent ready Client Platforms
Postman is the world's leading API platform, used by 35+ million developers to design, build, test, document, mock, monitor, and govern APIs across the entir...
Composite
73.7
Agent
57.2
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 73.7/100 · exemplar
Contract Quality
16.7 / 25
Developer Ergonomics
14.6 / 20
0 / 0
Operational Transparency
7.2 / 13
0 / 0
Discoverability
8.3 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
5.3 / 15
Agent readiness — 57/100 · agent ready
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
Documented Reversibility
0 / 6
MCP Server
12.0 / 12
Machine-Readable Auth served
9.0 / 10
Idempotency
0 / 9
Stable Error Semantics
8.0 / 8
Request/Response Examples partial
3.5 / 7
Rate-Limit Signaling documented
3.5 / 7
Typed Event Surface derived
1.5 / 6
Agent Skills unknown
4.5 / 5
Well-Known Catalog
0 / 4
Consent & Bot Identity
0 / 3
A2A Agent Card
0 / 8
Dry-Run / Simulate Mode
0 / 4
Delegated User Identity
6.0 / 6
Protected Resource Metadata
5.0 / 5
Registration Without a Human
6 / 6
Agentic Commerce Well-Known Document
0 / 5
Developing 2 39.3 – 54.2 Real signal across most facets with visible, nameable gaps.
2
Fiddler Developing agent aware Local-First & Offline-First Clients
Fiddler by Telerik (Progress Software) is a family of HTTP debugging proxy tools for capturing, inspecting, modifying, and replaying HTTP and HTTPS traffic b...
Composite
49.7
Agent
20.4
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 49.7/100 · developing
Contract Quality
0.0 / 25
Developer Ergonomics
12.4 / 20
0 / 0
Operational Transparency
7.5 / 13
0 / 0
Discoverability
6.8 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
5.3 / 15
Agent readiness — 20/100 · agent aware
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server documented
4.8 / 12
Machine-Readable Auth served
9.0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 7
Typed Event Surface
0 / 6
Agent Skills
5 / 5
Well-Known Catalog
0 / 4
Consent & Bot Identity
0 / 3
A2A Agent Card
0 / 8
Dry-Run / Simulate Mode
0 / 4
Delegated User Identity
6.0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
3
API Dash Developing agent ready Local-First & Offline-First Clients
API Dash is a beautiful AI-powered open-source cross-platform API client built with Flutter, available on Desktop (macOS, Windows, Linux) and Mobile. It prov...
Composite
45.5
Agent
29.9
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 45.5/100 · developing
Contract Quality
8.3 / 25
Developer Ergonomics
11.3 / 20
0 / 0
Operational Transparency
4.4 / 13
0 / 0
Discoverability
6.3 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
6.0 / 15
Agent readiness — 30/100 · agent ready
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
Documented Reversibility
0 / 6
MCP Server documented
4.8 / 12
Machine-Readable Auth bearer
3.5 / 10
Idempotency
0 / 9
Stable Error Semantics
8.0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 7
Typed Event Surface
0 / 6
Agent Skills derived
1.3 / 5
Well-Known Catalog
0 / 4
Consent & Bot Identity
0 / 3
A2A Agent Card
0 / 8
Dry-Run / Simulate Mode
0 / 4
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
Thin 6 26.2 – 39.2 Limited machine-readable signal beyond documentation a human can read.
4
Insomnia Thin agent aware Client Platforms
Insomnia is an open-source, cross-platform API development platform by Kong for designing, debugging, and testing HTTP, REST, GraphQL, gRPC, SOAP, WebSockets...
Composite
37.2
Agent
19.8
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 37.2/100 · thin
Contract Quality
15.6 / 25
Developer Ergonomics
6.2 / 20
0 / 0
Operational Transparency
3.8 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
2.5 / 15
Agent readiness — 20/100 · agent aware
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
Documented Reversibility
0 / 6
MCP Server
0 / 12
Machine-Readable Auth bearer
3.5 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
5
HTTPie Thin agent aware Client Platforms
HTTPie is a user-friendly command-line and web-based HTTP client designed for testing, debugging, and interacting with APIs and HTTP services. It provides ex...
Composite
31.5
Agent
20.0
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 31.5/100 · thin
Contract Quality
13.5 / 25
Developer Ergonomics
4.8 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 20/100 · agent aware
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
Documented Reversibility
6 / 6
MCP Server
0 / 12
Machine-Readable Auth
0 / 10
Idempotency
9 / 9
Stable Error Semantics
0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 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
4 / 4
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
6
Voiden Thin human only Local-First & Offline-First Clients
Voiden is an offline-first, Git-native API workspace that unifies API design, testing, and documentation in plain Markdown .void files stored alongside your ...
Composite
31.2
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 31.2/100 · thin
Contract Quality
4.5 / 25
Developer Ergonomics
2.4 / 20
0 / 0
Operational Transparency
5.1 / 13
0 / 0
Discoverability
6.4 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
7
Firecamp Thin human only Client Platforms
Firecamp is an open-source API development platform for designing, testing, and documenting REST, GraphQL, and WebSocket APIs. It provides multi-protocol pla...
Composite
31.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 31.1/100 · thin
Contract Quality
0.0 / 25
Developer Ergonomics
5.7 / 20
0 / 0
Operational Transparency
2.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
2.1 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
8
Hoppscotch Thin agent aware Client Platforms
Hoppscotch is a lightweight open-source browser-based API client supporting REST, GraphQL, WebSockets, SSE, and MQTT.
Composite
30.9
Agent
11.2
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 30.9/100 · thin
Contract Quality
0.0 / 25
Developer Ergonomics
7.1 / 20
0 / 0
Operational Transparency
6.2 / 13
0 / 0
Discoverability
5.8 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
2.1 / 15
Agent readiness — 11/100 · agent aware
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server
12.0 / 12
Machine-Readable Auth
0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
9
REST Client Thin human only Local-First & Offline-First Clients
REST Client is a Visual Studio Code extension developed by Huachao Mao that enables developers to send HTTP requests and view responses directly within the V...
Composite
27.1
Agent
3.8
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 27.1/100 · thin
Contract Quality
7.1 / 25
Developer Ergonomics
4.3 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 4/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server
0 / 12
Machine-Readable Auth
0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples documented
1.8 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
Emerging 20 11 – 26.1 More than an index entry but still mostly links rather than artifacts.
10
Requests Emerging human only CLI Clients & HTTP Libraries
Requests is a simple and elegant HTTP library for Python, designed for human beings. Published under the Apache2 license by the Python Software Foundation (P...
Composite
25.0
Agent
3.8
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 25.0/100 · emerging
Contract Quality
5.3 / 25
Developer Ergonomics
5.7 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Education & Research
1.6 / 15
Agent readiness — 4/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server
0 / 12
Machine-Readable Auth
0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples documented
1.8 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
11
Thunder Client Emerging human only Client Platforms
Thunder Client is a lightweight REST API client extension for Visual Studio Code created by Ranga Vadhineni, providing a clean interface for sending HTTP req...
Composite
24.8
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 24.8/100 · emerging
Contract Quality
3.7 / 25
Developer Ergonomics
4.3 / 20
0 / 0
Operational Transparency
3.8 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
12
Axios Emerging human only CLI Clients & HTTP Libraries
Axios is a promise-based HTTP client for the browser and Node.js with automatic JSON data transformation and request/response interceptors.
Composite
24.4
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 24.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
5.7 / 20
0 / 0
Operational Transparency
4.8 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
13
Node-Fetch Emerging human only CLI Clients & HTTP Libraries
node-fetch is a lightweight module that brings the Fetch API to Node.js for making HTTP requests. It is a client library, not an API service, and provides a ...
Composite
23.9
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 23.9/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.3 / 20
0 / 0
Operational Transparency
4.8 / 13
0 / 0
Discoverability
4.8 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
14
Wget Emerging human only CLI Clients & HTTP Libraries
GNU Wget is a free, open-source command-line utility for non-interactive downloading of files from the web using HTTP, HTTPS, FTP, and FTPS protocols. It sup...
Composite
23.0
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 23.0/100 · emerging
Contract Quality
5.7 / 25
Developer Ergonomics
3.1 / 20
0 / 0
Operational Transparency
2.4 / 13
0 / 0
Discoverability
6.6 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
15
Restfox Emerging human only Local-First & Offline-First Clients
Restfox is an offline-first, minimalistic HTTP and socket testing client for the web and desktop. It is an open-source alternative to Postman, supporting HTT...
Composite
21.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 21.1/100 · emerging
Contract Quality
4.5 / 25
Developer Ergonomics
1.9 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
16
cURL Emerging human only CLI Clients & HTTP Libraries
cURL is a command-line tool and library for transferring data with URLs. Originally released in 1997 by Daniel Stenberg, cURL is the de facto standard tool u...
Composite
20.8
Agent
3.8
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 20.8/100 · emerging
Contract Quality
1.6 / 25
Developer Ergonomics
6.2 / 20
0 / 0
Operational Transparency
5.1 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Education & Research
1.8 / 15
Agent readiness — 4/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server
0 / 12
Machine-Readable Auth
0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples documented
1.8 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
17
RestSharp Emerging human only CLI Clients & HTTP Libraries
RestSharp is a simple REST and HTTP API client library for .NET that wraps HttpClient with a fluent API for making HTTP requests with automatic serialization...
Composite
20.7
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 20.7/100 · emerging
Contract Quality
2.7 / 25
Developer Ergonomics
5.2 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
18
HTTPX Emerging human only CLI Clients & HTTP Libraries
HTTPX is a fully featured HTTP client for Python 3 with sync and async APIs, HTTP/1.1 and HTTP/2 support. It is broadly compatible with the popular requests ...
Composite
19.5
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 19.5/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.3 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Education & Research
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
19
Charles Proxy Emerging human only Local-First & Offline-First Clients
Charles Proxy is an HTTP proxy and HTTP monitor that enables developers to view all HTTP and SSL/HTTPS traffic between their machine and the Internet, includ...
Composite
18.5
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 18.5/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
5.2 / 20
0 / 0
Operational Transparency
1.0 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.5 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
20
Retrofit Emerging human only CLI Clients & HTTP Libraries
Retrofit is a type-safe HTTP client for Android and the JVM (Java and Kotlin) built by Square, turning HTTP API interfaces into callable Java objects with an...
Composite
18.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 18.1/100 · emerging
Contract Quality
4.5 / 25
Developer Ergonomics
0.0 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
6.3 / 10
Regulatory · Education & Research
0.7 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
21
Mitmproxy Emerging human only Local-First & Offline-First Clients
mitmproxy is a free and open source interactive HTTPS proxy that allows developers and security researchers to intercept, inspect, modify, and replay HTTP an...
Composite
16.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 16.1/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.8 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
6.3 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
22
Hurl Emerging human only CLI Clients & HTTP Libraries
Hurl is an open source command-line tool for running HTTP requests defined in a simple plain text format with built-in assertions for API testing.
Composite
15.8
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 15.8/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.4 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
4.6 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
23
Yaak Emerging agent ready Local-First & Offline-First Clients
Yaak is an open-source desktop API client for organizing and executing REST, GraphQL, WebSockets, Server Sent Events, and gRPC requests. Built with Tauri, Ru...
Composite
15.4
Agent
29.9
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 15.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.8 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
6.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.8 / 15
Agent readiness — 30/100 · agent ready
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
MCP Server
12.0 / 12
Machine-Readable Auth served
9.0 / 10
Idempotency
0 / 9
Stable Error Semantics
0 / 8
Request/Response Examples
0 / 7
Rate-Limit Signaling documented
3.5 / 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
Delegated User Identity
6.0 / 6
Protected Resource Metadata
5.0 / 5
Registration Without a Human
6 / 6
Agentic Commerce Well-Known Document
0 / 5
24
HTTP Client Emerging human only Local-First & Offline-First Clients
HTTP Client is JetBrains' built-in tool for creating, editing, and executing HTTP requests directly from the IDE. Requests are stored in .http and .rest file...
Composite
14.4
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 14.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.8 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.8 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
25
Milkman Emerging human only Local-First & Offline-First Clients
Milkman is an open-source, JavaFx-based, plugin-driven request/response workbench and desktop alternative to Postman and Insomnia. It supports multiple proto...
Composite
14.2
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 14.2/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.3 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
26
Xh Emerging human only CLI Clients & HTTP Libraries
xh is a friendly and fast command-line HTTP client written in Rust, designed as a modern, high-performance alternative to HTTPie. It reimplements HTTPie's re...
Composite
13.2
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 13.2/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.9 / 20
0 / 0
Operational Transparency
3.8 / 13
0 / 0
Discoverability
5.7 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
27
Got Emerging human only CLI Clients & HTTP Libraries
Got is a human-friendly and powerful HTTP request library for Node.js with support for streams, retries, and pagination.
Composite
11.7
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 11.7/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
5.2 / 20
0 / 0
Operational Transparency
1.7 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
28
Kreya Emerging human only Local-First & Offline-First Clients
Kreya is a GUI client for gRPC, REST, GraphQL, WebSocket, and Server-Sent Events APIs. All data is stored in git-diffable files for easy reviews and versioni...
Composite
11.5
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 11.5/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.9 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
5.5 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
29
Grpcurl Emerging human only CLI Clients & HTTP Libraries
grpcurl is an open source command-line tool for interacting with gRPC servers, like curl for gRPC with support for service reflection and JSON encoding.
Composite
11.3
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 11.3/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.9 / 20
0 / 0
Operational Transparency
3.4 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
Minimal 5 0 – 10.9 Index entry only; little beyond a description and a link.
30
Paw Minimal human only Local-First & Offline-First Clients
Paw (now RapidAPI for Mac) is a full-featured HTTP client that lets you test and describe the APIs you build or consume. It provides a native macOS API testi...
Composite
9.8
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 9.8/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.9 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
4.8 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
31
Nightingale Minimal human only Local-First & Offline-First Clients
Nightingale REST Client is a modern, resource-friendly REST API client for Windows.
Composite
9.4
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 9.4/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
2.4 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.9 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
32
ReqBin Minimal human only Local-First & Offline-First Clients
ReqBin is an online HTTP/REST API client for testing API requests directly from the browser without plugins or software installation. It supports all HTTP me...
Composite
6.8
Agent
0.0
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 6.8/100 · minimal
Contract Quality
2.7 / 25
Developer Ergonomics
0.0 / 20
0 / 0
Operational Transparency
0.0 / 13
0 / 0
Discoverability
4.8 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
1.6 / 15
Agent readiness — 0/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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
0 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
33
Ezy Minimal human only Local-First & Offline-First Clients
ezy is a graphical gRPC and gRPC-Web client for testing and debugging gRPC services with an intuitive desktop interface.
Composite
6.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 6.1/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
0.0 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5
34
OkHttp Minimal human only CLI Clients & HTTP Libraries
OkHttp is an efficient HTTP and HTTP/2 client for Android and Java applications with connection pooling and transparent GZIP.
Composite
6.1
Agent
2.5
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Composite quality — 6.1/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
0.0 / 20
0 / 0
Operational Transparency
1.4 / 13
0 / 0
Discoverability
3.9 / 10
Regulatory · Horizontal (data, software, accessibility, platform)
0.0 / 15
Agent readiness — 3/100 · human only
Machine-Readable Contract
0 / 18
Agentic Access Contract
0 / 10
Documented Reversibility
0 / 6
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 documented
3.5 / 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
Delegated User Identity
0 / 6
Protected Resource Metadata
0 / 5
Registration Without a Human
0 / 6
Agentic Commerce Well-Known Document
0 / 5