Developer tools / API testing11 tools

Best API testing tools

Send requests to an API and inspect the responses. Facts come from each tool's own pages, and every score says where it comes from. How we rank

Tools: 11
Researched: 4
Free option: 4
Only listed: 7

Ranked by signals we can measure or quote: website health, the facts each tool's own pages state, and community discussion. Nothing here has been hands-on tested yet, so this is not a quality test. How the signals rank works

Quick answer

No signup needed: Yaak
Files stay on your device: Yaak

Based on what each tool's own pages say. A tool is left out when its pages say it varies or do not say. Details are listed under each tool.

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Want two of these head to head? Compare tools side by side.

1
Checkly
Free optionSignup unclearFile handling unclearHealth 4.5
CompareOpen Checkly
Details and sources
Free tier
Hobby plan costs $0: 10 uptime monitors, up to 1,000 browser check runs and 10,000 API check runs per month (hard-capped), 6 locations, 2-minute maximum frequency, 1 user, 1 dashboard. Email, Slack and webhook alerts. Raw data kept 7 days.
Paid plan
Prices in $ (currency not named). Starter: Detect (uptime and synthetic) $24/month billed annually. Team: Detect $64/month billed annually. Status pages, AI root cause and Platform bundles are priced separately. Enterprise is a custom quote. The page says save up to 20% on annual billing.
Signup
Sign-up is through a Get Started link to the signup page; the page does not explicitly say an account is required. The FAQ says no credit card is needed to get started.
Watermark
Not applicable.
Where files go
Data may be processed in the United States. Test results are kept by plan: Hobby and Starter 7 days raw and 30 days aggregated; Team 30 days raw and 1 year aggregated; Enterprise 180 days raw and 25 months aggregated. No retention period is given for account data.
From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy. Prices and limits change; check the tool before you rely on them.
Full page for Checkly
2
Insomnia
Free optionSignup unclearFile handling unclearHealth 4.2Community 4
CompareOpen Insomnia
Details and sources
Free tier
Essentials plan is $0 per user/month: Git Sync projects for up to 3 users, unlimited Cloud/Local projects, unlimited collection runs and environments, 1,000 mock server requests per month, Inso CLI. Scratch Pad is local-only and free.
Paid plan
Pro $12 per user/month (annual payment schedule; toggle shows Save 17% for annual). Enterprise $45 per user/month, self-serve up to 50 users; billing period not clearly stated. Extra mock requests add-on: $10 per 25,000.
Signup
Not stated for the free plan. The page says the Scratch Pad can be used without logging in.
Watermark
Not applicable.
Where files go
Privacy policy names Google Cloud for hosting and says data may be stored outside the EU. It does not say whether project data is stored locally or in the cloud. Optional end-to-end encryption for project data. No retention periods given; account deletion is permanent.
From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy policy. Prices and limits change; check the tool before you rely on them.
Full page for Insomnia
3
Postman
Free optionSignup unclearFile handling unclearHealth 4.5Community 3.6
CompareOpen Postman
Details and sources
Free tier
The Free plan supports core solo API development and testing for individual developers. The page says: “Free supports core solo API development and testing for individual developers.”
Paid plan
Not stated.
Signup
A signup is required to use Postman. The page says: “Sign In Sign Up for Free.”
Watermark
Not stated.
Where files go
Not stated.
From the tool's own pages, checked 2026-11-08. Sources: Pricing. Prices and limits change; check the tool before you rely on them.
Read automatically by a program, not by a person. Each fact quotes the sentence it came from, and a fact is shown only if that sentence is on the page. Where a page did not say, it reads “Not stated.”
Full page for Postman
4
Yaak
Free optionNo signupFiles stay on your deviceHealth 4.3
CompareOpen Yaak
Details and sources
Free tier
Free for personal use with no license. Commercial use has a 30-day trial starting on first launch, with no credit card or signup required.
Paid plan
Individual $79 per year; Individual lifetime $399 one-time; Business $149 per user per year. Annual billing only. Currency shown only as $. 50% discount for eligible residents of lower purchasing power countries.
Signup
Personal use and trial need no account. Licenses are tied to a Yaak account.
Watermark
Not applicable.
Where files go
Privacy policy says requests, responses, environments and workspace data are stored on-device and not sent to the company. Operational metadata (license status, app version, OS) is sent to the company. Retention periods not stated.
From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy. Prices and limits change; check the tool before you rely on them.
Full page for Yaak

API testing: tools compared
Tool	Free option	Signup	Your files	Scores	Compare, open or show details
1Checkly	Yes	Unclear	Unclear	Health 4.5Signals 4.0	CompareOpen
Free tier Hobby plan costs $0: 10 uptime monitors, up to 1,000 browser check runs and 10,000 API check runs per month (hard-capped), 6 locations, 2-minute maximum frequency, 1 user, 1 dashboard. Email, Slack and webhook alerts. Raw data kept 7 days. Paid plan Prices in $ (currency not named). Starter: Detect (uptime and synthetic) $24/month billed annually. Team: Detect $64/month billed annually. Status pages, AI root cause and Platform bundles are priced separately. Enterprise is a custom quote. The page says save up to 20% on annual billing. Signup Sign-up is through a Get Started link to the signup page; the page does not explicitly say an account is required. The FAQ says no credit card is needed to get started. Watermark Not applicable. Where files go Data may be processed in the United States. Test results are kept by plan: Hobby and Starter 7 days raw and 30 days aggregated; Team 30 days raw and 1 year aggregated; Enterprise 180 days raw and 25 months aggregated. No retention period is given for account data. From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy. Prices and limits change; check the tool before you rely on them. Full page for Checkly
2Insomnia	Yes	Unclear	Unclear	Health 4.2Community 4Signals 3.9	CompareOpen
Free tier Essentials plan is $0 per user/month: Git Sync projects for up to 3 users, unlimited Cloud/Local projects, unlimited collection runs and environments, 1,000 mock server requests per month, Inso CLI. Scratch Pad is local-only and free. Paid plan Pro $12 per user/month (annual payment schedule; toggle shows Save 17% for annual). Enterprise $45 per user/month, self-serve up to 50 users; billing period not clearly stated. Extra mock requests add-on: $10 per 25,000. Signup Not stated for the free plan. The page says the Scratch Pad can be used without logging in. Watermark Not applicable. Where files go Privacy policy names Google Cloud for hosting and says data may be stored outside the EU. It does not say whether project data is stored locally or in the cloud. Optional end-to-end encryption for project data. No retention periods given; account deletion is permanent. From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy policy. Prices and limits change; check the tool before you rely on them. Full page for Insomnia
3Postman	Yes	Unclear	Unclear	Health 4.5Community 3.6Signals 3.9	CompareOpen
Free tier The Free plan supports core solo API development and testing for individual developers. The page says: “Free supports core solo API development and testing for individual developers.” Paid plan Not stated. Signup A signup is required to use Postman. The page says: “Sign In Sign Up for Free.” Watermark Not stated. Where files go Not stated. From the tool's own pages, checked 2026-11-08. Sources: Pricing. Prices and limits change; check the tool before you rely on them. Read automatically by a program, not by a person. Each fact quotes the sentence it came from, and a fact is shown only if that sentence is on the page. Where a page did not say, it reads “Not stated.” Full page for Postman
4Yaak	Yes	Not needed	On your device	Health 4.3Signals 3.9	CompareOpen
Free tier Free for personal use with no license. Commercial use has a 30-day trial starting on first launch, with no credit card or signup required. Paid plan Individual $79 per year; Individual lifetime $399 one-time; Business $149 per user per year. Annual billing only. Currency shown only as $. 50% discount for eligible residents of lower purchasing power countries. Signup Personal use and trial need no account. Licenses are tied to a Yaak account. Watermark Not applicable. Where files go Privacy policy says requests, responses, environments and workspace data are stored on-device and not sent to the company. Operational metadata (license status, app version, OS) is sent to the company. Retention periods not stated. From the tool's own pages, checked 2026-11-01. Sources: Pricing, Privacy. Prices and limits change; check the tool before you rely on them. Full page for Yaak

Free option, signup and file handling come from each tool's own pages (“Unclear” means they do not say). Hover a score for what it means. Tick “Compare” on two to four tools to read them side by side.

Answers come from each tool's own pages (“Unclear” means they do not say). Tick “Compare” on two to four tools to read them side by side.

Also listed (7, not yet tested)

Each of these answered when we visited its site. We have not tested them or recorded facts, so they are in alphabetical order, not ranked.

Apidog
Apidog is listed for: api testing.
Open
Bruno
Bruno is the Git-native API client for REST, GraphQL, gRPC and Websocket. A local and open-source solution to Postman. Fast, developer-first, and no cloud syncing.
Open
Hoppscotch
Helps you create requests faster, saving precious time on development.
Open
HTTPie
Making APIs simple and intuitive for those building the tools of our time.
Open
RapidAPI
RapidAPI is listed for: api testing.
Open
ReqBin
ReqBin is listed for: api testing.
Open
Swagger
Simplify API development for users, teams, and enterprises with our open source and professional toolset. Findogut how Swagger can help you and get started today.
Open