API Evangelist Trend Report
The State of API Clients
The API client market, and the one cut in this series where the measuring instrument stops fitting the category. Only 3 of 35 publish an API of their own. That is not a gap in the research — it is a market deliberately building without a service surface, and Postman is the reason. Scores the six platforms that do operate a service, and reads the other twenty-nine as the offline-first counter-movement they advertise themselves to be.
Read the report →
$500
· PDF + Word + AI data bundle, instant download
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
35 providers
Exemplar 1 66+ 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
69.4
Agent
58.1
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 69.4/100 · exemplar
Contract Quality
17.7 / 25
Developer Ergonomics
15.2 / 20
Commercial Clarity
15.3 / 20
Operational Transparency
7.2 / 13
Governance
5.7 / 12
Discoverability
8.3 / 10
Agent readiness — 58/100 · agent ready
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
MCP Server
12 / 12
Machine-Readable Auth
10 / 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 derived
1.5 / 6
Agent Skills
5 / 5
Well-Known Catalog
4 / 4
Consent & Bot Identity
0 / 3
A2A Agent Card
0 / 8
Dry-Run / Simulate Mode
0 / 4
Developing 2 42 – 55.9 Real signal across most facets with visible, nameable gaps.
2
Insomnia Developing 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
45.4
Agent
30.6
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 45.4/100 · developing
Contract Quality
17.9 / 25
Developer Ergonomics
5.7 / 20
Commercial Clarity
5.3 / 20
Operational Transparency
3.1 / 13
Governance
7.0 / 12
Discoverability
6.5 / 10
Agent readiness — 31/100 · agent aware
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 10
MCP Server
0 / 12
Machine-Readable Auth
10 / 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
3
Hoppscotch Developing agent aware Client Platforms
Hoppscotch is a lightweight open-source browser-based API client supporting REST, GraphQL, WebSockets, SSE, and MQTT.
Composite
43.6
Agent
19.4
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 43.6/100 · developing
Contract Quality
12.0 / 25
Developer Ergonomics
6.5 / 20
Commercial Clarity
12.1 / 20
Operational Transparency
7.2 / 13
Governance
0.0 / 12
Discoverability
5.7 / 10
Agent readiness — 19/100 · agent aware
Machine-Readable Contract
18 / 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 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
Thin 4 28 – 41.9 Limited machine-readable signal beyond documentation a human can read.
4
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
40.9
Agent
21.6
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 40.9/100 · thin
Contract Quality
16.2 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
7.9 / 20
Operational Transparency
1.7 / 13
Governance
7.0 / 12
Discoverability
5.9 / 10
Agent readiness — 22/100 · agent aware
Machine-Readable Contract
18 / 18
Agentic Access Contract derived
2.5 / 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 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
5
Thunder Client Thin 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
30.3
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 30.3/100 · thin
Contract Quality
4.4 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
5.3 / 20
Operational Transparency
3.8 / 13
Governance
8.3 / 12
Discoverability
6.9 / 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 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
6
Retrofit Thin 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
29.0
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 29.0/100 · thin
Contract Quality
5.7 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
8.3 / 12
Discoverability
6.5 / 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 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
7
Wget Thin 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
29.0
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 29.0/100 · thin
Contract Quality
7.3 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
8.3 / 12
Discoverability
6.9 / 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 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
Emerging 20 13 – 27.9 More than an index entry but still mostly links rather than artifacts.
8
REST Client Emerging 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
27.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 27.7/100 · emerging
Contract Quality
6.9 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
8.3 / 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 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
9
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
27.3
Agent
4.7
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 27.3/100 · emerging
Contract Quality
4.4 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
8.3 / 12
Discoverability
5.9 / 10
Agent readiness — 5/100 · 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 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
10
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
27.2
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 27.2/100 · emerging
Contract Quality
5.7 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 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 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
11
Bruno Emerging human only Local-First & Offline-First Clients
Bruno is an open-source, Git-native, offline-first API client for exploring and testing APIs. It stores collections directly on the filesystem as plain text ...
Composite
25.4
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 25.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
3.0 / 20
Commercial Clarity
11.1 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 12
Discoverability
7.6 / 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 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
12
Voiden Emerging 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
25.2
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 25.2/100 · emerging
Contract Quality
5.7 / 25
Developer Ergonomics
0.4 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.0 / 13
Governance
8.3 / 12
Discoverability
6.7 / 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 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
13
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
23.6
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 23.6/100 · emerging
Contract Quality
3.2 / 25
Developer Ergonomics
2.6 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 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 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
14
API Dash Emerging human only 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
19.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 19.7/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.6 / 20
Commercial Clarity
5.3 / 20
Operational Transparency
5.1 / 13
Governance
0.0 / 12
Discoverability
6.7 / 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 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
15
Fiddler Emerging human only Local-First & Offline-First Clients
Fiddler by Telerik (Progress Software) is a suite of HTTP debugging proxy tools for capturing, inspecting, modifying, and replaying HTTP and HTTPS traffic be...
Composite
19.1
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 19.1/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
3.0 / 20
Commercial Clarity
7.9 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
6.5 / 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 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
16
Firecamp Emerging 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
18.0
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 18.0/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
3.0 / 20
Commercial Clarity
5.3 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 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 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
17
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
17.4
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 17.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
3.0 / 20
Commercial Clarity
7.4 / 20
Operational Transparency
1.0 / 13
Governance
0.0 / 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 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
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
15.8
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 15.8/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
1.2 / 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 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
19
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
15.6
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 15.6/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 12
Discoverability
6.5 / 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 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
20
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
15.4
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 15.4/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
3.0 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
5.1 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
21
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
15.0
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 15.0/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
5.1 / 13
Governance
0.0 / 12
Discoverability
5.0 / 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 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
22
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
14.6
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 14.6/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 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 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
23
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
13.9
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 13.9/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 12
Discoverability
4.8 / 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 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
24
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
13.9
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 13.9/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.1 / 13
Governance
0.0 / 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 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
25
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
13.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 13.7/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
4.8 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
26
Yaak Emerging human only 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
13.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 13.7/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
6.7 / 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 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
27
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
13.0
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 13.0/100 · emerging
Contract Quality
0.0 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 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 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
Minimal 8 0 – 12.9 Index entry only; little beyond a description and a link.
28
cURL Minimal 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
12.8
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 12.8/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.3 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
2.4 / 13
Governance
0.0 / 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 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
29
Kreya Minimal 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
12.8
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 12.8/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
5.7 / 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 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
30
Grpcurl Minimal 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
12.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 12.7/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
3.8 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
31
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
10.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 10.7/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
32
Nightingale Minimal human only Local-First & Offline-First Clients
Nightingale REST Client is a modern, resource-friendly REST API client for Windows.
Composite
10.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 10.7/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
33
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
10.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 10.7/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
34
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
10.7
Agent
3.2
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 10.7/100 · minimal
Contract Quality
0.0 / 25
Developer Ergonomics
1.7 / 20
Commercial Clarity
3.2 / 20
Operational Transparency
1.7 / 13
Governance
0.0 / 12
Discoverability
4.1 / 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 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
35
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
10.4
Agent
0.0
Kin Score
How this is scored →scored 2026-08-17 · rubric v0.11.0
Composite quality — 10.4/100 · minimal
Contract Quality
3.2 / 25
Developer Ergonomics
2.2 / 20
Commercial Clarity
0.0 / 20
Operational Transparency
0.0 / 13
Governance
0.0 / 12
Discoverability
5.0 / 10
Agent readiness — 0/100 · 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
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