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The Lytms Index· API development toolsUS region · updated Aug 16, 2026
The Lytms Index / API development tools

Which tool your team designs, tests and documents APIs in

Summary

As of Aug 16, 2026, the market’s strongest steer is Postman — followed by Swagger and Insomnia.

The engines name 11 of the 20 products measured here — the other 9 are never mentioned in an answer.

Postman is also the most searched for by name on this board.

20 products scored · scores are 0-100 · measured continuously · updated Aug 16, 2026 · about this score
Rank 1 · the market’s pick
Postmanpostman.com85

The AI-native API Platform — their words · Aug 14, 2026

named by Claude, Gemini, Google's AI Mode and Google's AI Overview · not in the top results where buyers search · 142,900 searches a month by name

The rest of the board, ranked by what the market says — every score’s receipts one click away.

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Density
2
Swaggerswagger.ioThe Future of AI Relies on API Qualitymovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Claude, Gemini, Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand126,400 searches a month by name
78
3
Insomniainsomnia.restAI-ready APIs Built Smarter. Tested Faster. Governed Better.movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Claude, Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand14,920 searches a month by name
75
4
Stoplightstoplight.ioDesign, document, and build APIs faster.movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Claude, Gemini, Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand27,100 searches a month by name
70
5
Hoppscotchhoppscotch.comMake Better APIsmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand91,000 searches a month by name
69
6
JMeterjmeter.apache.orgApache JMeter™movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Claude, Gemini and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand22,660 searches a month by name
65
7
Brunousebruno.comThe Git-native API clientmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand210 searches a month by name
64
8
Apiaryapiary.ioPowerful API Design Stack. Built for Developers.movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Claude and Google's AI Mode
  • Search resultsnot in the top results where buyers search
  • Buyer demand33,100 searches a month by name
63
9
SoapUIsoapui.orgDownload the Best API Testing Tool for your Needsmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Gemini
  • Search resultsnot in the top results where buyers search
  • Buyer demand4,990 searches a month by name
51
10
Kongkonghq.commovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Google's AI Mode and Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
47
11
Rest-assuredrest-assured.iomovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnamed by Google's AI Overview
  • Search resultsnot in the top results where buyers search
  • Buyer demand90 searches a month by name
47
12
Workatoworkato.comThe Control and Execution Platform for Enterprise AImovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand14,800 searches a month by name
40
13
Boomiboomi.comThe Infrastructure That Turns AI Into Actionmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand12,100 searches a month by name
38
14
News APInewsapi.aiBest news APIfor your productmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand4,710 searches a month by name
36
15
Apideckapideck.comAll the accounting integrations you need.Already done.movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29
16
Fireapifireapi.ioThe Global Engine for APIs & Software Toolsmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29
17
Hybiscushybiscus.devBuild stunning PDF reports with zero design experience.movement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29
18
MobiLoudmobiloud.commovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29
19
Treblletreblle.comEnterprise Runtime Intelligence Platformmovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29
20
Zapierzapier.comThe automation layer for agentic AImovement · measures nothing until the next capture
Why it ranks here →
  • AI answersnot named in AI answers
  • Search resultsnot in the top results where buyers search
  • Buyer demand0 searches a month by name
29

What the engines say

Verbatim, from the answers themselves. We quote what an engine said and when it said it — never a paraphrase, and never our summary of it.

Open-source options like Hoppscotch and Insomnia also offer collaborative workspaces, but require balancing cloud features against pricing or self-hosting needs.

Google's AI Overview on Hoppscotch · Aug 16, 2026

Insomnia - A REST client that's clean and intuitive, with good support for environment variables, request chaining, and GraphQL.

Claude on Insomnia · Aug 16, 2026

Apache JMeter - Better for load testing and performance testing at scale. cURL - The command-line classic for simple API testing, though less user-friendly than GUI tools.

Claude on JMeter · Aug 16, 2026

It is best for developers who prioritize data privacy and want to store API collections as plain-text files directly inside a Git repository without cloud lock-in. - Insomnia by Kong is a clean, developer-first API client.

Google's AI Mode on Kong · Aug 16, 2026

However, here are some of the most popular and highly-regarded options: API Development & Testing Tools: Postman - One of the most popular, with a user-friendly interface, collections, mock servers, and automated testing capabilities.

Claude on Postman · Aug 16, 2026

Functional and Performance Testing Specialists: * SoapUI (SmartBear): A widely used open-source tool specifically designed for functional and performance testing of SOAP and REST APIs.

Gemini on SoapUI · Aug 16, 2026

Engines asked for this category: Claude, Gemini, Google's AI Mode and Google's AI Overview.

Check it yourself

Ask ChatGPT about this market →

You will not get our answer back, and you should not expect to. A single reply varies by the day, the account and the wording; the board is what several engines named across a fixed set of buying questions, recorded over time. What you can check is the part that matters — whether the products we say the engines name are the ones you are shown.

What decides a position

Four signals, chosen because a vendor cannot buy any of them directly. Each is a measurement of what the market does, not of what a company says.

AI answers

What AI engines answer when buyers ask what to use for a job.

Search results

Where the product stands in the search results buyers actually see for the category’s buying queries — including who owns the answer box.

Buyer demand

How many buyers search for the product by name.

Movement

Whether the product is gaining or losing ground against the others in its market, measured between dated captures rather than claimed.

A product is scored on the signals we could actually measure for it, and a signal we could not measure is left out rather than counted as zero. This is not a quality rating and not a recommendation. It measures how present and how well-regarded a product is across public surfaces — a different question from whether it is right for you.

Cite this

Free to quote, with attribution. Add your own accessed date if your style needs one — the date below is when we measured, which is the one that decides whether a number is still current.

The Lytms Index. "Which tool your team designs, tests and documents APIs in." Lytms AI. Measured Aug 16, 2026. https://lytms.ai/best/api-development

Prefer the numbers? Download the API development tools board as CSV — every row and every evidence line exactly as shown above, nothing extra.

Markets next to this one

Related because the rosters overlap, which is a fact about the products we track rather than a judgment about the markets. Each row says how much.

Workflow & agentic automation

2 of these 20 products also appear on that roster — Workato and Zapier.

Something wrong? Tell us. Nobody pays to be listed here, and claiming a listing never changes a position.