Freemium
API Clients · API Tools
API platform for building, testing, documenting and sharing APIs.
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Discover the 27 best browser-based tools for api tools. Run directly in any modern browser without local installation. Curated, compared, and updated for developers.
| Tool | Pricing | Platforms | Top Strength | Link |
|---|---|---|---|---|
| Postman | freemium | desktop, web | The API client standard — collections, environments, docs, mocking | Details → |
| Hoppscotch | freemium | web | Lightweight, open-source API development ecosystem in the browser. | Details → |
| Apidog | freemium | desktop, web | All-in-one API platform for design, debug, mock, test and document. | Details → |
| Swagger | freemium | web | OpenAPI tooling suite by SmartBear: UI, editor, codegen and more. | Details → |
| Stoplight | freemium | web | Design-first API platform for specs, docs, mocking and governance. | Details → |
| WireMock | free | cli, web | Flexible API mocking and service virtualization for HTTP. | Details → |
| Requestly | freemium | web, extension | Open-source HTTP interception: modify requests, mock, and debug in browser. | Details → |
| JSONPlaceholder | free | web | Free fake REST API for prototyping and testing. | Details → |
| httpbin | free | web | HTTP request and response service for testing clients. | Details → |
| Webhook.site | freemium | web | Instantly inspect and test incoming webhooks with a temporary URL. | Details → |
Showing top 10 of 27. Browse the full grid below.
API Clients · API Tools
API platform for building, testing, documenting and sharing APIs.
API Clients · API Tools
Lightweight, open-source API development ecosystem in the browser.
API Clients · API Tools
All-in-one API platform for design, debug, mock, test and document.
API Documentation · API Tools
OpenAPI tooling suite by SmartBear: UI, editor, codegen and more.
API Documentation · API Tools
Design-first API platform for specs, docs, mocking and governance.
API Mocking · API Tools
Flexible API mocking and service virtualization for HTTP.
Tunneling & Debugging · API Tools
Open-source HTTP interception: modify requests, mock, and debug in browser.
API Mocking · API Tools
Free fake REST API for prototyping and testing.
API Mocking · API Tools
HTTP request and response service for testing clients.
API Mocking · API Tools
Instantly inspect and test incoming webhooks with a temporary URL.
Authentication · API Tools
Okta's identity platform for authentication and authorization.
Authentication · API Tools
Complete auth and user management with beautiful prebuilt components.
Authentication · API Tools
Official resource for the OAuth 2.0 authorization framework.
Email · API Tools
Developer-first email API with React Email templates.
Email · API Tools
Long-standing transactional email API for developers.
Email · API Tools
Email sandbox that safely captures mail from dev and staging.
Email · API Tools
Self-hosted email testing tool with a web UI, catches local mail.
Payments · API Tools
The standard payments platform with excellent developer APIs.
Payments · API Tools
Merchant-of-record payments and licensing for digital products.
Payments · API Tools
Indonesia's leading payment gateway (GoTo): QRIS, VA, cards and more.
Payments · API Tools
Payment gateway for Indonesia and Southeast Asia markets.
Payments · API Tools
Merchant-of-record payments for SaaS — global tax, invoicing and subscriptions handled for you.
Payments · API Tools
Subscription infrastructure for mobile apps — cross-platform in-app purchases, entitlements and analytics.
Payments · API Tools
Open-source payments and monetization for developers — checkouts, subscriptions and license keys, MoR model.
Authentication · API Tools
Open-source auth infrastructure with a beautiful admin console — OIDC/OAuth, SSO and user management, self-hostable.
Scheduling & Booking · API Tools
Open-source scheduling infrastructure — Calendly alternative with booking links, teams and an API you can self-host.
Scheduling & Booking · API Tools
The scheduling standard — shareable booking links, round-robin teams, reminders and integrations.