Best Free API Tools in 2026

Generate lifelike AI voices in 29 languages, clone voices, and enable real-time speech

4.6/5 across G2 and Capterra · 1,236 ratings, Sep 2026

ElevenLabs provides the most realistic AI voice technology for content creators and developers. Generate lifelike speech from text in 29 languages. Clone voices with just minutes of audio samples. Real-time voice synthesis for conversational AI applications. API for developers building voice-enabled products. AI voices indistinguishable from human speech.

GraphQL developer platform for building APIs

4.7/5 on G2 · 9,819 ratings, Aug 2026

Apollo Studio provides visibility into your GraphQL APIs. See which queries clients actually run, track performance by field and resolver, and catch schema changes that would break existing clients. The explorer lets developers browse and test queries against your schema interactively. Schema checks in CI prevent breaking changes from reaching production. Contract testing validates that client queries match server capabilities. Teams running GraphQL in production need observability. Apollo Studio provides the monitoring and governance that keep GraphQL APIs healthy as they evolve.

Dynamically query APIs, code, and cloud resources with SQL for Zero-ETL insights.

4.6/5 on G2 · 5,705 ratings, Aug 2026

Steampipe is an open-source data-access layer that allows users to query cloud APIs, code, and other data sources using standard SQL. It eliminates the need for complex ETL processes by providing a 'Zero-ETL' approach, treating live cloud configurations and other data as a dynamic database. This enables developers, security professionals, and operations teams to gain real-time insights without syncing or relying on outdated data. The platform leverages a vast library of plugins (over 500) to connect to various services like AWS, Azure, GCP, and many others, organizing their metadata into discoverable SQL tables. This unified SQL interface simplifies tasks such as compliance auditing, security posture assessment, cost optimization, and operational troubleshooting. Steampipe can be used as a CLI tool, or integrated as a PostgreSQL FDW or SQLite extension, making it a versatile tool for anyone needing to analyze and manage their cloud infrastructure and API data efficiently.

Official Shopify MCP server giving AI assistants access to Shopify docs, GraphQL API schemas, and code validation tools.

4.4/5 on G2 · 5,126 ratings, Aug 2026

Shopify MCP Server is the official Model Context Protocol server from Shopify that gives AI assistants direct access to Shopify's development documentation, GraphQL API schemas, and code validation tools. It enables developers to build Shopify apps faster by letting AI tools like Claude, Cursor, and VS Code provide accurate, up-to-date guidance based on current Shopify APIs. The Dev MCP server searches across all Shopify documentation, explores GraphQL schemas to discover available types, queries, and mutations, and validates generated code against Shopify's APIs. Supported validation covers GraphQL operations, JavaScript/TypeScript component checks, Liquid theme validation for syntax errors and broken references, and individual codeblock testing. It works with the Admin GraphQL API, Storefront API, Customer Account API, Functions, Liquid, Partner API, Payment Apps API, Web Components, POS UI Extensions, and more. Shopify also offers a separate Storefront MCP server for commerce data access (products, carts, customer info) and a Customer Accounts MCP server for order tracking and returns. The Dev MCP server requires Node.js 18+ and is free for all Shopify developers.

API platform for building and using APIs

4.6/5 across G2 and Capterra · 2,311 ratings, Sep 2026

Postman is an API development platform used by over 30 million developers and 500,000 organizations worldwide. It provides a unified workspace for designing, testing, documenting, and monitoring APIs across HTTP, GraphQL, gRPC, WebSocket, and MQTT protocols. Teams can collaborate through shared workspaces, collections, and mock servers while maintaining version control via native Git integration. The platform includes an AI-powered agent mode for automating repetitive API tasks, an API catalog for internal service discovery, and a CLI for CI/CD pipeline integration. Postman supports the full API lifecycle from spec design through production monitoring, making it the industry standard for API-first development workflows.

Reliable event infrastructure for webhooks and external event streams.

4.5/5 across G2 and Capterra · 2,271 ratings, Oct 2026

This platform provides robust event infrastructure designed to manage the full lifecycle of external events, from ingestion to delivery and observability. It ensures that every event, whether from third-party webhooks or outbound event streams, is received, processed, and monitored reliably at scale, offering complete visibility and control. It's built for engineering teams dealing with event-driven systems, offering features like built-in event queueing to handle traffic spikes and destination failures, automatic issue management with event replay capabilities, and flexible routing and transformation of events. The platform integrates seamlessly with any tech stack, supporting various backends and allowing declarative infrastructure definition through API or Terraform. The core value proposition is to eliminate the headaches associated with managing webhooks and external events, such as missed events, retries, and debugging. By providing a scalable, secure, and compliant solution, it allows developers to focus on building their applications rather than on the complexities of event infrastructure, ensuring peace of mind even with high volumes of event data.

Connect 1000+ apps with AI-powered no-code automations

4.7/5 across G2 and Capterra · 916 ratings, Sep 2026

Albato is an AI-driven integration platform that connects 1,000+ applications through a no-code visual builder. It supports two-way data synchronization, webhook triggers, scheduled automations, and bulk data migration between business tools. With built-in AI capabilities for advanced models, teams can add intelligent data transformation directly into workflows. Albato positions itself as a cost-effective Zapier alternative at roughly lower pricing, serving 200,000+ users from small businesses to enterprises with a white-label embedded integration option.

Multi-carrier e-commerce shipping API with discounted rates

4.6/5 across G2 and Capterra · 903 ratings, Sep 2026

Shippo provides shipping API and discounts. Multi-carrier shipping for e-commerce-labels and tracking with rate shopping. The carrier options are many. The rates are discounted. The API is straightforward. E-commerce shipping through APIs often uses Shippo for multi-carrier access.

Send, parse, and validate emails with a reliable developer API

4.1/5 across G2 and Trustpilot · 1,850 ratings, Sep 2026

Mailgun is an email API service for developers sending transactional and marketing emails. Reliable delivery with detailed logs and analytics. Email validation catches bad addresses before sending. Intelligent routing optimizes deliverability. Parse incoming emails with webhooks. Integrations with popular frameworks and languages. The email infrastructure developers trust for critical communications.

Connect 1,500+ apps with millions of pre-built automations

4.7/5 on G2 · 695 ratings, Mar 2026

Integrately is a workflow automation platform connecting 1,500+ applications with over 20 million pre-built automation templates. It enables users to set up integrations between business tools like CRMs, email marketing platforms, project management apps, and payment processors without coding. The platform offers a visual workflow builder with branching logic, webhooks, auto-retry, and multi-step automations. Integrately positions itself as a simpler, more affordable alternative to Zapier, with a free plan offering 100 tasks/month and paid plans offering various task volumes.

Federated content platform with GraphQL

4.5/5 across G2 and Capterra · 745 ratings, Sep 2026

Hygraph (formerly GraphCMS) is a headless CMS that pioneered GraphQL-first content APIs. The platform focuses on content federation - connecting and unifying content from multiple sources. Hygraph is known for its powerful GraphQL API, content localization, and flexible content modeling. The platform is popular among teams building complex content architectures that need to combine content from different systems into a unified API.

Instant search and AI-powered discovery for your site

4.6/5 across G2 and Capterra · 528 ratings, Sep 2026

Algolia is a search and discovery API platform offering instant search, AI-powered recommendations, personalization, and analytics for websites and applications.

Get documents signed online with a simple, legally-binding e-signature solution

3.7/5 across G2 and Trustpilot · 2,316 ratings, Sep 2026

Dropbox Sign is electronic signature software for getting documents signed online. Simple interface makes signing easy for recipients. Templates save time on frequently-used documents. API enables embedding signatures in your applications. Audit trails provide legally-binding proof. Integrations with Dropbox, Google Drive, and business tools. E-signatures made simple for businesses of all sizes.

Manage and deliver digital content across all channels via APIs

4.4/5 across G2 and Capterra · 409 ratings, Sep 2026

Contentful is a composable content platform that enables enterprises to create, manage, and deliver digital content across websites, apps, and devices via APIs.

API design, testing, and documentation in one platform

4.8/5 on G2 · 226 ratings, Sep 2026

Apidog combines API design, testing, and documentation in one tool. Design your API spec, test endpoints as you build them, and generate documentation automatically-without switching between different applications. Mock servers let frontend and backend teams work in parallel. Automated testing catches regressions when APIs change. The interface is modern and the workflow is streamlined compared to juggling other API tools. Development teams looking to consolidate their API workflow find Apidog does what used to require multiple tools.