Alternatives to OpenAPI Generator
Compare OpenAPI Generator alternatives for your business or organization using the curated list below. SourceForge ranks the best alternatives to OpenAPI Generator in 2026. Compare features, ratings, user reviews, pricing, and more from OpenAPI Generator competitors and alternatives in order to make an informed decision for your business.
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1
Blackbird API Development
Ambassador
Accelerate Development of Prod-Ready APIs. AI-Powered Code Gen, Mocking in Minutes, and On-Demand Ephemeral Test Environments. * Design Efficiently: Generate standardized OpenAPI specs with AI assistance, allowing you to begin coding faster. * Mock Effortlessly: Create shareable API mocks without manual coding, enabling rapid validation. * Automate Repetitive Tasks: Utilize AI to automatically generate boilerplate code for both client and server-side APIs. * Test Effectively: Access publicly available URLs for testing in a production-like test environment through Blackbird's ephemeral testing environments. * Debug Seamlessly: Set breakpoints and debug directly from your preferred IDE with Blackbird's integrated debugging tools. * Deploy Smoothly: Utilize a 24/7 hosted environment for progressive and repeated testing without reconfiguration, facilitated by Blackbird's containerized deployment.Starting Price: $69/month -
2
Archbee
AiurLabs
Documentation tool for high-performing teams. Archbee is the place to centralize your company's information. Unify knowledge in product, engineering, support, marketing, sales. Use cases: • Manage team knowledge • Developer & API docs • Documentation sites • Document internal processes • Collaborate on documents • Onboard & train teammates • Create documentation for your customers • Bring your own domain Integrations: Slack, Airtable, Loom, Trello, Lucidchart, Typeform, Mindmeister, Prezi, Miro, Google Docs, Google Sheets, Google Slides, Figma, Invision, Framer, Abstract, Marvel, Github, GraphQL, Swagger/Open API, Numeracy, Mode Analytics, Codepen, Intercom, Google Analytics.Starting Price: $60 per month -
3
Qdrant
Qdrant
Qdrant is a vector similarity engine & vector database. It deploys as an API service providing search for the nearest high-dimensional vectors. With Qdrant, embeddings or neural network encoders can be turned into full-fledged applications for matching, searching, recommending, and much more! Provides the OpenAPI v3 specification to generate a client library in almost any programming language. Alternatively utilise ready-made client for Python or other programming languages with additional functionality. Implement a unique custom modification of the HNSW algorithm for Approximate Nearest Neighbor Search. Search with a State-of-the-Art speed and apply search filters without compromising on results. Support additional payload associated with vectors. Not only stores payload but also allows filter results based on payload values. -
4
Swagger Codegen
SmartBear
Swagger Codegen can simplify your build process by generating server stubs and client SDKs for any API, defined with the OpenAPI (formerly known as Swagger) specification, so your team can focus better on your API’s implementation and adoption. Moving from design to development has never been easier with Swagger Codegen in SwaggerHub. API Definition files can be used to create stubs in popular languages, like Java, Scala, and Ruby, with just a few clicks.Starting Price: Free -
5
AutoRest
Microsoft
The AutoRest tool generates client libraries for accessing RESTful web services. Input to AutoRest is a spec that describes the REST API using the OpenAPI specification format and streamlines the creation of client code across multiple programming languages, including C#, Java, Python, TypeScript, and Go. This automation enhances consistency and efficiency in API consumption, reducing the manual effort required to develop and maintain client libraries. AutoRest operates through a flexible pipeline that processes OpenAPI input files, transforming them into a code model which is then utilized by language-specific generators to produce client code adhering to each language's design guidelines. The tool supports both OpenAPI 2.0 and 3.0 specifications, ensuring compatibility with a wide range of APIs. Developers can install AutoRest on Windows, macOS, or Linux systems, with installation facilitated via Node.js.Starting Price: Free -
6
NSwag
Rico Suter
NSwag is a comprehensive Swagger/OpenAPI 2.0 and 3.0 toolchain for .NET, .NET Core, ASP.NET Core, and TypeScript, written in C#. It enables developers to generate OpenAPI specifications from existing API controllers and create client code from these specifications. NSwag combines functionalities similar to Swashbuckle (for OpenAPI/Swagger generation) and AutoRest (for client generation) into a single toolchain, eliminating the need for both. Key features include the ability to generate Swagger 2.0 and OpenAPI 3.0 specifications from C# ASP.NET (Core) controllers, serve these specifications via ASP.NET (Core) middleware with integrated Swagger UI or ReDoc, and generate C# or TypeScript clients/proxies from the specifications. NSwag offers multiple usage methods, including a user-friendly Windows GUI (NSwagStudio), command-line interfaces compatible with Windows, Mac, and Linux, and integration into C# code via NuGet packages.Starting Price: Free -
7
Kiota
Microsoft
Kiota is a client, plugin, and manifest generator for HTTP REST APIs described by OpenAPI. Available as a command-line tool and a Visual Studio Code (VS Code) extension, Kiota enables developers to search for API descriptions, filter and select specific endpoints, and generate models and a chained method API surface in various programming languages. This approach eliminates the need to depend on different API clients for each API and allows for precise generation of the required API surface area. Additionally, Kiota facilitates participation in the Microsoft Copilot ecosystem by enabling the generation of API plugins. The VS Code extension enhances the Kiota experience with a rich user interface, supporting features such as searching for API descriptions, filtering endpoints, and generating API clients. Users can select desired endpoints and generate clients, plugins, or other outputs, with completion notifications and easy access to generated outputs within the workspace.Starting Price: Free -
8
Swagger
SmartBear
Simplify API development for users, teams, and enterprises with the Swagger open source and professional toolset. Find out how Swagger can help you design and document your APIs at scale. The power of Swagger tools starts with the OpenAPI Specification — the industry standard for RESTful API design. Individual tools to create, update and share OpenAPI definitions with consumers. SwaggerHub is the platform solution to support OpenAPI workflows at scale. Swagger open source and pro tools have helped millions of API developers, teams, and organizations deliver great APIs. Swagger offers the most powerful and easiest to use tools to take full advantage of the OpenAPI Specification. -
9
Zuplo
Zuplo
We’re reinventing API & MCP management for everybody, from startups to enterprises. Add authentication, analytics, rate-limiting, and developer documentation to your APIs and MCP servers in minutes. Protect your API by adding rate-limiting with Zuplo in minutes, and add over 50 available plugins like authentication to your API with a single click. Zuplo was built on the edge and deployed to +300 data centers in the world, which makes multi-cloud deployments first-class. With Zuplo you can run different workloads in different clouds while enforcing a unified set of security policies. Zuplo is the only API gateway that runs your OpenAPI spec directly. Leverage the OpenAPI ecosystem to build your API, and then deploy it to Zuplo without additional configuration. Zuplo automatically generates beautiful docs for your API. You can customize the docs with markdown and devs can self-serve API Keys directly from your docs. You can also directly generate hosted MCP servers from your OpenAPI.Starting Price: $0 per month -
10
Konfig
Konfig
Konfig is a developer tool that automates the generation of SDKs, documentation, demos, and tutorials for REST APIs, facilitating seamless onboarding for external developers. By importing an OpenAPI Specification or Postman Collection, Konfig automatically produces SDKs in popular programming languages, including TypeScript, Python, Java, C#, PHP, Ruby, Go, Swift, and Dart. The platform ensures high-quality SDKs by identifying and rectifying errors in the OpenAPI Specification through its linter and writing test cases to prevent API updates from breaking existing SDKs. Konfig also generates branded, user-friendly documentation that auto-updates with any changes to the API specification, maintaining consistency between documentation and SDKs. Additionally, it allows for the creation of engaging demos and tutorials using familiar Markdown, enabling users to run code in-browser for hands-on learning. -
11
ATA
ATA
ATA is an AI-powered API management platform that centralizes design, testing, governance, documentation, and lifecycle workflows into a single intelligent workspace to help teams design, build, test, maintain, and govern APIs with higher quality and collaboration. It keeps API code, design documentation, specifications, test cases, and release notes in sync, reducing manual effort and drift while supporting OpenAPI specs, mock servers for frontend progress without backend readiness, and scheduled API monitoring to detect slow responses, timeouts, or failures early. It includes a Developer Studio for design-first OpenAPI creation and version control, E2E Test Automation with AI-generated robustness and security tests, mock servers, chained API workflows, and UI automation testing, and a Documentation Portal that centralizes API docs with multi-editor support, version management, secure access control, and auto-linked live endpoints. -
12
Speakeasy
Speakeasy
Speakeasy is a platform that enhances API integration by generating handwritten, type-safe SDKs in over nine programming languages, including TypeScript, Python, Go, Java, and C#. These SDKs improve API integration times by up to 60% by eliminating the need for users to write boilerplate code, reducing common implementation errors, and expanding API accessibility across various programming communities. The platform also simplifies the creation of Terraform providers, allowing for the definition of resources and operations, automatic validation from OpenAPI specifications, and handling complex API landscapes. Additionally, Speakeasy offers end-to-end testing workflows to enforce API standards and protect against breaking changes, as well as SDK documentation that remains up-to-date with compilable usage snippets for every SDK method. Trusted by top API companies, Speakeasy's solutions are designed to provide robust SDKs, Terraform providers, and comprehensive testing tools.Starting Price: $250 per month -
13
Fern
Fern
Stripe-level SDKs and Docs for your API. Offer type-safe SDKs in the most popular languages. Let Fern do the heavy lifting of generating and publishing client libraries so your team can focus on building the API. Import your API definition, whether it's in OpenAPI or Fern's simpler format. Select which code generators you'd like to use: TypeScript, Python, Java, Go, Ruby, C#, Swift. Fern semantically versions and publishes packages to each registry (e.g. npm, pypi, maven). Beautiful API documentation that reflects your brand.Starting Price: $250 per month -
14
DapperDox
DapperDox
DapperDox is open source, and provides rich, out-of-the-box, rendering of your OpenAPI specifications, seamlessly combined with your GitHub flavoured Markdown documentation, guides, and diagrams. Publish your API Swagger specifications like never before. Document multiple API specifications as a suite of products, and cross-reference as required. The built-in API explorer enables API experimentation from within the documentation pages, and can seamlessly integrate into your authentication and API key model. DapperDox can proxy your developer platform, allowing full integration of API key generation and management alongside your specifications and guides. Change themes and present your documentation in the style you like. DapperDox was created by API documentation authors for one purpose, to improve the quality and usability of the API documentation they were providing for other developers.Starting Price: Free -
15
Redocly
Redocly
Beautiful API documentation loved by teams and API consumers. At last, API documentation your whole team will be proud of. Publish beautiful API reference docs in seconds and style them in minutes. Tick every developer's favorite box right out of the box, three panels, a try-it console, generated code samples, SEO-friendly, even friendlier search. Nobody likes outdated docs and scope creep. Maintain API documentation with your favorite source control integrated with our cloud app workflows. We support them all, including on-premise and API management providers. Launch a developer portal in minutes reusing your API definitions as assets. Add tutorials, quick-start guides, and developer tooling with incredible customization. Validate, lint, and bundle multi-file API definitions. Write always on-spec OpenAPI documents. Plug in your API reference and customize every nook & cranny to wow your API consumers.Starting Price: $69 per month -
16
Apitive Studio
Apitive
Design, Document, Mock and Publish your APIs in OpenAPI 3.0 specification. A sleek UI that allows its users to design REST APIs intuitively. Product managers can now be less or notdependent on engineering teams to create API designs; thus increasing time to market. Workbench includes a refined review tool that allows users to submit their API designs for peer reviews. Achieve enterprise wide interface design standardization with Apitive Studio by creating reusable data models and global policies. Share them across various products and provide uniformity in your API Designs and Implementations. API designs are only as good as its document. Auto generate complete API documentation as web pages that provides both technical and business documentation to its consumers. Apitive Studio also deploys the documentation as a portal at pre-defined location for consumption saving time and effort. Socialize your APIs with external consumers and get instant validation. -
17
RapiDoc
RapiDoc
Free of any frameworks, setups, configs, build steps, or packaging. Can be used with any framework or just with vanilla Javascript. Style it to your heart's content. Change font, logo, colors, and theme. Inject external HTML or embed it into another HTML document. Create beautiful, customizable, interactive API documentation from OpenAPI specification. Use It just like any other HTML tag, Change its attribute using JavaScript and see it react to those changes. Basic knowledge of HTML is all that's required. Minimal dependencies, no runtime, and no virtual DOM ensure the lowest memory consumption, Just the native and raw speed of modern browsers. Loved by tech writers, designers, dev-ops, testers, and developers alike, due to its simplicity, interoperability, and powerful features. No special build-steps, runtime, or framework are required. Comes with built-in console to Try out the APIs. Supports authentication mechanism. No validation ensures you can test negative cases.Starting Price: Free -
18
SwaggerHub
SmartBear
SwaggerHub is an integrated API design and documentation platform, built for teams to drive consistency and discipline across the API development workflow. Accelerate your team’s design process without any loss in quality or organizational style consistency with a powerful Editor that’s fully compliant with the latest Swagger (OpenAPI) standards. A Powerful Editor equipped with smart error feedback and syntax auto-completion. Style Validators for ensuring design consistency across multiple APIs. API Mocking to virtualize operations without any code. Domains for storing, reusing and referencing common OAS syntax across multiple APIs. Have your API design and development centralized on a single location, allowing your teams to seamlessly collaborate on new APIs, or discover existing APIs on a centralized platform. Coordinate your entire API lifecycle from a central internal repository, hosted on the cloud.Starting Price: $90 per month -
19
Procurement Service Bus (PSB)
eConnect
The Procurement Service Bus (PSB) provides a cloud managed connection to eDelivery networks like the Peppol network. Specially designed for large volumes and low latency with automatic scaling. Build with redundancy and high availability in mind. The shared cloud approach is centrally monitored for optimal utilization and predictable costs. Additional services are available, like target-transformation, automatic retry and party discovery. The Procurement Service Bus is more than just an AccessPoint As A Service (APAAS). We connect the Peppol network with the enterprise systems. The interface is based on REST with OAUTh 2.0 layer. The API’s are self explanatory and made visible with the OpenApi UI. The swagger.json file can be downloaded on top of the OpenAPI UI main page and can be used to generate code for several languages. If you choose to generate code, we recommend using OpenAPI Generator. -
20
create-api.dev
Kong
Create-API.dev is an AI-powered OpenAPI specification builder by Kong that lets you generate high-quality API specs in seconds through a simple chat interface. By messaging the service, you provide your desired endpoints or rough outline, and an underlying Google LLM crafts complete, standards-compliant OpenAPI definitions that are ready to share, test, and ship. As a lightweight, web-based tool, it requires no installation. The generated specs can be exported in standard YAML or JSON formats for seamless integration with your existing API gateways and documentation pipelines. Create-API.dev operates under Google’s Generative AI Prohibited Use Policy and advises discretion before relying on or publishing any AI-generated content.Starting Price: Free -
21
Ceptor API Management
Ceptor
Features range from a Service Repository with built-in support for authoring APIs to full support for Ceptor's many proven authentication and authorization methods over full API Gateway functionality to a customizable API Developer Portal supporting self-registration which allows you to expose your APIs to both internal and external consumers. Where other products focus mostly on monetizing APIs, Ceptor API Management is more focused on providing flexibility to enterprising solving complex use cases that go far beyond simply publishing and subscribing to APIs. Ceptor API Management allows you to create as many API Groups as you need, you can use Ceptor's default templates or create your own. Ceptor supports various different types of APIs including OpenAPI, SOAP / WSDL and plain HTTP. You can document your APIs using the OpenAPI Specification or Ceptor’s built-in HTML editor. -
22
RepreZen API Studio
RepreZen
Build APIs that click with client apps. RepreZen API Studio is an integrated workbench that brings API-first design into focus for your whole team, harmonizes your API designs, and generates APIs that click into client apps. Effortlessly. Full-featured OpenAPI editor with content assist, customizable templates, outline navigation & more for fast, focused API design. Live documentation view gives you immediate clarity & insight from the API user's perspective. Interactive diagram lets you visualize the API as you design. Generate & view in any browser to give API users a fast, intuitive overview. Split a large Swagger API spec into multiple files, even share & reuse API components across projects & teams! Edit, navigate, document & generate, all fully compliant with OpenAPI standards. Consolidate & simplify complex multi-file projects to a single file, for easy downstream code generation & docs presentation.Starting Price: $22 per month -
23
Globessey Data Server
Adaptive Recognition
Globessey Data Server (GDS) is a centralized data server and middleware solution designed to collect, manage, and visualize extensive traffic data from various endpoints. It seamlessly integrates with Adaptive Recognition's ANPR/LPR cameras and third-party devices, enabling efficient data aggregation and analysis. Built on the robust ELK stack, GDS offers secure data storage, user-friendly dashboards, and advanced visualization tools, including heatmaps and geofencing filters. Its intuitive interface facilitates easy deployment and device registration, while the documented OpenAPI and SDK samples support flexible development. GDS is compatible with both Windows and Linux operating systems, making it a versatile tool for traffic management, smart city infrastructure, and security applications. -
24
tap
Digital Society
Turn spreadsheets and data files into production-ready APIs without writing backend code. Upload CSV, JSONL, Parquet and other formats, clean and join them with familiar SQL, and expose secure, documented endpoints instantly. Built-in features include auto-generated OpenAPI docs, API key security, geospatial filters with H3 indexing, usage monitoring, and high-performance queries. You can also download transformed datasets anytime to avoid vendor lock-in. Works for single files, combined datasets, or public data portals with minimal setup. Key features - Create secure, documented APIs directly from CSV, JSONL, and Parquet. - Run familiar SQL queries to clean, join, and enrich data. - No backend setup or servers to configure or maintain. - Auto-generated OpenAPI documentation for every endpoint you create. - Secure endpoints with API keys and isolated storage for safety. - Geospatial filters, H3 indexing, and fast, optimised queries at scale.Starting Price: $10/month -
25
Insomnia
Kong
Design, debug, and test APIs like a human, not a robot. Finally, a workflow you'll love. The Collaborative API Design Tool for designing, testing and managing OpenAPI specifications. The Desktop API client for REST and GraphQL. Make requests, inspect responses. Quickly create and group requests, specify environment variables, authentication, generate code snippets, and more. Get all the details on responses. View the whole request timeline, status codes, body, headers, cookies, and more. Create workspaces, folders, environments, drag-and-drop requests, and easily import and export your data. Create, edit, lint, debug, preview, and manage all of your OpenAPI specs in one collaborative API design editor. Generate configuration for common API gateways such as the Kong API Gateway, and Kong for Kubernetes. Sync your API designs with source control such as Github / Gitlab, and deploy directly to API Gateways such as Kong with one click.Starting Price: $5 per month -
26
42Crunch
42Crunch
Your most valuable intelligence isn’t AI, it’s your developers. Empower them with tools to be the driving force behind API security – ensuring continuous, unparalleled protection across the entire API lifecycle. Push your OpenAPI definition to your CI/CD pipeline and automatically audit, scan and protect your API. Audit your OpenAPI / Swagger file against 300+ security vulnerabilities, we’ll rank them by severity level and tell you exactly how to fix them – making security a seamless part of your development lifecycle Enforce a zero-trust architecture by ensuring all your APIs meet a set security standard before production, scan the live API endpoints for potential vulnerabilities, and automate redeployment. Ensure security of all your APIs from design to deployment, get detailed insight about attacks on APIs in production – and protect against threats – without impacting performance. -
27
SOAPSonar
Crosscheck Networks
Validate the functional behavior of APIs with client input simulations. Success criteria rules provide validation and regression testing of API behavior. Tests can be run on-demand or automated. Supports latest OpenAPI standards for automatically parsing OpenAPI documents and building test cases for all of the defined operations. Test authentication schemes including OAuth, SAML, PKI, Basic Auth, Amazon Auth, and Kerberos. Verify SSO tokens and cookies. Create behavior baselines and run regression tests to determine if any breakage or change of behavior occurs. Includes JSON and XML Diff capability. Test encryption and decryption of JSON, XML, REST, and SOAP message patterns. Simulate load from multiple virtual clients to measure and validate the performance criteria of the target APIs. Dynamic security and identity provide real world simulated inputs. Built-in support for AWSv4 signatures to authenticate to and test Amazon AWS APIs.Starting Price: $80/month -
28
Kusk
Kubeshop
Kusk is an Open Source API Gateway that allows you to develop, monitor and deploy your APIs in a matter of minutes. Kusk powers-up your API workflows with mocked responses and validated requests out-of-the-box and automates the deployment of the API Gateway with your favorite GitOps workflows. Have a single source of truth for your API by using the OpenAPI Standard, meaning no additional configuration files are needed!Starting Price: Free -
29
Qarbon LATTICE
Qarbon Technologies
Qarbon LATTICE, a SaaS-based orchestration platform can provide a single, OpenAPI interface between data centers and customers. Qarbon will transform the status quo for digital infrastructure customers. LATTICE is a SaaS-based platform that onboards the entire tech stack of each data center, providing users with a single, open, and secure interface between the operator and their business systems. LATTICE provides customers with an OpenAPI-compliant interface between data centers and their customers. OpenAPI is the leading industry specification for a machine-readable interface definition language for both humans and machines. LATTICE enables seamless, standardized reporting of ESG data, including scope I and II CO2 emissions. Customers will be able to access real-time, standardized power, water, and CO2 data, for data center-related ESG reporting through a button-click. Qarbon is a platform that securely transfers data between workflow management and data center systems. -
30
Writerside
JetBrains
The most powerful development environment, now adapted for writing documentation. Use a single authoring environment, eliminating the need for a wide array of tools. With the built-in Git UI, an integrated build tool, automated tests, and a ready-to-use and customizable layout, you can focus on what matters most, your content. You can now combine the advantages of Markdown with those of semantic markup. Stick to one format, or enrich markdown with semantic attributes and elements, Mermaid diagrams, and LaTeX math formulas. Ensure documentation quality and integrity with 100+ on-the-fly inspections in the editor as well as tests in live preview and during build. The preview shows the docs exactly as your readers will see them. Preview a single page in the IDE, or open the entire help website in your browser without running the build. Reuse anything, from smaller content chunks to entire topics or sections of your TOC.Starting Price: Free -
31
Dash
Kapeli
Dash gives your Mac instant offline access to 200+ API documentation sets. Dash is an API documentation browser and code snippet manager. Dash instantly searches offline documentation sets for 200+ APIs, 100+ cheat sheets, and more. You can even generate your own docsets or request docsets to be included. Dash comes with 200+ offline documentation sets. You can choose which documentation sets to download and Dash will take care of the rest, making sure they are kept up to date. You can also generate your own docsets, request docsets or download docsets from third-party sources. All documentation sets have been generated and are maintained with the utmost care. Dash integrates with package managers to generate documentation sets for anything you might need, as well as provide custom documentation sources of their own. Store snippets of code. Easily reuse snippets. Expand snippets in any app. Organize snippets with tags, syntax highlighting, and variable placeholders.Starting Price: Free -
32
Langdock
Langdock
Native support for ChatGPT and LangChain. Bing, HuggingFace and more coming soon. Add your API documentation manually or import an existing OpenAPI specification. Access the request prompt, parameters, headers, body and more. Inspect detailed live metrics about how your plugin is performing, including latencies, errors, and more. Configure your own dashboards, track funnels and aggregated metrics.Starting Price: Free -
33
Apache ServiceComb
ServiceComb
Open-source, full-stack microservice solution. With out-of-the-box, high performance, compatible with popular ecology, and multi-language support. Service contract guarantee based on OpenAPI. One-click scaffolding, out of the box, speeds up the building of microservice applications. The ecological extension supports multiple development languages such as Java/Golang/PHP/NodeJS. Apache ServiceComb is an open-source solution for microservices. It consists of multiple components that can be flexibly adapted to different scenarios through the combination of components. This guide can help you get started quickly with Apache ServiceComb, which is the best place to start trying for first-time users. To decouple the programming and communication models, so that a programming model can be combined with any communication models as needed. Application developers only need to focus on APIs during development and can flexibly switch communication models during deployment.Starting Price: Free -
34
Gentoro
Gentoro
Gentoro is a platform built to empower enterprises to adopt agentic automation by bridging AI agents with real-world systems securely and at scale. It uses the Model Context Protocol (MCP) as its foundation, allowing developers to automatically convert OpenAPI specs or backend endpoints into production-ready MCP Tools, without writing custom integration code. Gentoro takes care of runtime concerns like logging, retries, monitoring, and cost optimization, while enforcing secure access, auditability, and governance policies (e.g., OAuth support, policy enforcement) whether deployed in a private cloud or on-premises. It is model- and framework-agnostic, meaning it supports integration with various LLMs and agent architectures. Gentoro helps avoid vendor lock-in and simplifies tool orchestration in enterprise environments by managing tool generation, runtime, security, and maintenance in one stack. -
35
Specmatic
Specmatic
Specmatic offers a no-code, specification-driven, visual approach to API testing by leveraging API specifications to automatically execute positive and negative tests. Specmatic Studio offers broad format and protocol support across REST, SOAP, GraphQL, gRPC, WebSockets, and asynchronous messaging systems (message queues and event-driven APIs). The platform provides a comprehensive toolkit for API development and testing, utilizing specs as the single source of truth. Key features include: • Contract testing across various protocols • Service virtualization and mocking • Workflow and resiliency testing • Backward compatibility checks to prevent breaking changes • Open-source testing tools for OpenAPI, MCP and SOAP • Postman collection import for spec creation Specmatic focuses on functional correctness, contract compliance, resiliency, and compatibility testing. Genie assists API design, enabling interactive validation of the API spec prior to generating an MCP server.Starting Price: $2500 per month (50 seats) -
36
Sigmify
Business Integration Systems India
Make your teams more effective. Help them perform their tasks by giving them access to the correct information. Unify the data scattered over documents and emails in one place making daily work more streamlined. You have invested in a lot of ‘systems’. Some purchased, some outsourced, some custom developed. You may have an ERP for your core function. Sigmify OpenAPIs provide the necessary framework for you to integrate your existing applications with SigmifySigmify can become your single access point for the apps which you are using and which you want to build in future. Conversations hold the secret – to not only deal with tasks but also solve critical bottlenecks/escalations. Facebook displayed the power of mere conversations. It set the tone for creating social networks.Sigmify is the equivalent of “Facebook” for Enterprises/Organisations. Why? Because better communication at the workplace is the key to better collaboration.Starting Price: $5.00/month/user -
37
Javalin
Javalin
You never extend classes and you rarely implement interfaces. Javalin is just a few thousand lines of code on top of Jetty, and its performance is equivalent to raw Jetty code. Due to its size, it's very easy to reason about the source code. Other Java and Kotlin web frameworks usually offer one version for each language. Javalin is being made with inter-operability in mind, apps are built the same way in both Java and Kotlin. Javalin runs on top of Jetty, one of the most used and stable web servers on the JVM. You can configure the Jetty server fully, including SSL and HTTP3 and everything else that Jetty offers. Many lightweight Java and Kotlin web frameworks don't support OpenAPI, but Javalin does. -
38
SwytchCode
SwytchCode
SwytchCode is an AI-powered “solutions engineer” platform that transforms API and SDK documentation into interactive developer experiences. It allows API publishers to upload an OpenAPI spec, Postman collection, or SDK, and within minutes, the system generates multilingual code samples (15+ programming languages), live playgrounds, and ready-to-run workflows that reduce developer integration time from hours to under two minutes. It supports smart testing with mock calls, analytics to surface developer drop-off or usage issues, and multi-step workflow generation via drag-and-drop or natural-language prompts, enabling API teams to significantly reduce support costs and improve adoption while maintaining high uptime and broad language support. With a mission to eliminate friction between APIs and developers, SwytchCode is a unified AI-driven interface that sits alongside your API.Starting Price: $19 per month -
39
Alphadoc
Alphadoc
Your open API spec is at the core of Alphadoc, create tutorials and intuitive sequence diagrams on top of it. Always in sync with your OAS spec through versioning. We will help you document your SDKs, long code snippets, and entire demo applications. Easily create code walkthroughs, combining API references, variables and more. Interactive docs let developers try out API calls with real data, and from your documentation and guides. With auto-updating endpoints on your pages, you can effortlessly describe API calls without the need for manual copying and pasting. We provide you with the building blocks to create intuitive documentation. You can also embed endpoints, diagrams and code walkthroughs in websites, blogs, or wherever you want.Starting Price: €150 per month -
40
Alibaba Cloud API Gateway
Alibaba Cloud
API Gateway provides API lifecycle management services, including API publishing, management, maintenance, and monetization. It enables simple and fast microservice integration, front and back end separation, and system integration at low costs and low risks. You can use API Gateway to share functions and data with your partners and third-party developers. Provides API documentation, SDKs, and API version management to reduce the daily maintenance costs. API Gateway supports distributed deployment and auto-scaling to respond to large numbers of requests with low latency. API Gateway activation and API management are free of charge. You only need to pay for APIs that you have called. API Gateway supports permission management, traffic throttling, monitoring, and alarms. You can allow API Gateway to access your services in the intranet without causing any security issues.Starting Price: $0.45 per million calls -
41
API Agent
IBM
API Agent in IBM API Connect is a watsonx.ai–powered assistant that automates core tasks across the entire API lifecycle via a natural‑language, conversational interface. Built on an agentic framework, it lets teams rapidly generate OpenAPI specifications, mocked responses, and rich documentation for design‑first projects, or connect to backend data sources, build application code, and auto‑deploy to Code Engine for code‑first workflows, all without manual setup. To combat API sprawl, API Agent intelligently searches your existing API catalog by simple description prompts, recommending reusable endpoints and reducing duplication. It enforces governance by validating specs against organizational rulesets, suggesting or applying fixes automatically, and boosts quality with a built‑in testing suite that generates and runs semantic test cases to catch issues early. -
42
Apiboost
Apiboost
Enterprise-level developer portal providing next-level access control, robust API productization, and advanced API key management. One portal for internal, external, and partner-specific APIs, robust API documentation and guides, delegated control for partners and teams, and flexible content editing with granular editorial permissions and workflows. Use Apiboost’s OpenAI integration to accelerate the development of your API guides and related documentation. Apiboost is a cutting-edge API Platform, that transforms how companies approach APIs, unlocking new revenue streams and digital efficiencies. We treat your APIs as valuable products, make smart future-oriented decisions, and achieve unparalleled growth with Apiboost. From multiple Identity management integrations to granular access control Apiboost has you covered. With Apiboost, you can wave goodbye to tedious development processes and embrace a streamlined approach to API management. -
43
REST United
REST United
REST United is a platform that simplifies the process of generating Software Development Kits (SDKs) for REST APIs across multiple programming languages, including PHP, Python, Ruby, ActionScript (Flash), C#, Android, Objective-C, Scala, and Java. In just five simple steps, users can create SDKs accompanied by highly customizable documentation featuring easy-to-follow example code, enhancing developer engagement. The platform also leverages the Postman Chrome plug-in to facilitate testing and debugging of REST APIs, streamlining the development workflow. For those designing their own REST APIs using frameworks like Node.js, Ruby Sinatra, Scala Scalatra, or Java JAX-RS, REST United offers assistance in generating server-side code. Support is readily available, with the promise of responses within 12 hours to any inquiries. Overall, REST United aims to make REST API development more accessible and efficient by providing tools that bridge the gap between API design and implementation.Starting Price: $1 per month -
44
Hubql
Hubql
Hubql is your local-first API Client to test, share, document and ship APIs faster. Start with any OpenAPI spec either through introspection via URL or using our server libraries passing your API schema. Hubql is built as local-first library storing your data offline. Our API client runs in browser only either as a local server plugin for example as NestJS plugin or distributed directly via CDN as JS library. Organize your APIs in workspaces and Hubs. Share your API Hubs with your team members and collaborate on the same API collection. Store your environment variables in your workspace and use them in your API requests. No need to copy-paste your variables anymore. -
45
Gram
Speakeasy
Gram is an open source platform that enables developers to create, curate, and host Model Context Protocol (MCP) servers effortlessly, by transforming REST APIs (via OpenAPI specs) into AI-agent-ready tools without code changes. It guides users through a workflow: generating default tooling from API endpoints, scoping down to relevant tools, composing higher-order custom tools by chaining multiple calls, enriching tools with contextual prompts and metadata, and instantly testing within an interactive playground. With built-in support for OAuth 2.1 (including Dynamic Client Registration or user-authored flows), it ensures secure agent access. Once ready, these tools can be hosted as production-grade MCP servers, complete with centralized management, role-based access, audit logs, and compliance-ready infrastructure, including Cloudflare edge deployment and DXT-packaged installers for easy distribution.Starting Price: $250 per month -
46
Read the Docs
Read the Docs
Spend your time on writing high quality documentation, not on the tools to make your documentation work. Read the Docs simplifies software documentation by automating building, versioning, and hosting of your docs for you. We will host your documentation for free, forever. There are no tricks. We help over 100,000 open source projects share their docs, including a custom domain and theme. Whenever you push code to your favorite version control service, whether that is GitHub, BitBucket, or GitLab, we will automatically build your docs so your code and documentation are never out of sync. We build and host your docs for the web, but they are also viewable as PDFs, as single page HTML, and for eReaders. No additional configuration is required. We can host and build multiple versions of your docs so having a 1.0 version of your docs and a 2.0 version of your docs is as easy as having a separate branch or tag in your version control system.Starting Price: $5 per month -
47
MetaMate
MetaMate
MetaMate is an open source semantic service bus that provides a unified API for accessing diverse data sources, including APIs, blockchains, websites, and peer-to-peer networks. By mapping vendor-specific data representations onto an abstract schema graph, MetaMate enables seamless interaction with various services. Its community-driven approach allows contributors to add new types and fields, ensuring the system evolves with real-world data. The platform's type system is derived from widely adopted data transmission technologies such as GraphQL, gRPC, Thrift, and OpenAPI, facilitating compatibility across different protocols. MetaMate enforces backward compatibility programmatically, ensuring that services and applications built on it remain functional over time. Additionally, its command-line interface can generate slim, typed SDKs tailored to specific project needs, covering only the desired subset of the overall schema graph.Starting Price: Free -
48
Bump.sh
Bump.sh
Bump.sh is the place for API developers to centralize all of their API documentation. Working with REST, Event-Drivent Architecture, or a mix of API technologies? Bump.sh is the only tool on the market that supports OpenAPI/Swagger, AsyncAPI, and soon more (such as GraphQL, SOAP, and gRPC). Plug Bump.sh into your CI, use our CLI, or upload your specification files manually, and benefit from a stunning UI that definitely contrasts with the legacy tools on the market. Enjoy all of the nifty UX details: we know devs will like it, as they were imagined by devs. Unique on the market: every time you publish a new version of your API documentation, Bump.sh automatically detects changes, publishes a changelog, and sends alerts to subscribe readers if the changes break anything.Starting Price: $149 per month -
49
Amadeus Digital Commerce
Amadeus
Increase your digital sales by offering your customers a smooth booking experience, across different touchpoints and devices. Our user-friendly API offers you the flexibility and functionalities to build best in class front-ends with a fast time-to-market. Adapt quickly to customer demand using the tools, data models, and open technology offered by Amadeus Digital Commerce and the digital developer toolkit, part of the Amadeus Digital Experience suite. Tap into wider UI development resources thanks to open technology. Amadeus’ Digital Commerce API follows the industry-standard OpenAPI specifications (Swagger) model and is based on RESTful technology and the JSON data format. Achieve quick adoption from your developers and reduce UI development costs, with a data model that is easy-to-use and requires no specialist PSS knowledge. Achieve higher conversion rates and increase brand loyalty thanks to the smooth booking process and differentiation capabilities. -
50
Bijira
WSO2
WSO2 Bijira is an AI-native, cloud-native SaaS API management platform built to manage the full lifecycle of APIs, including design, security, governance, deployment, and monitoring, across internal, external, egress, and AI-driven APIs in hybrid and multi-cloud environments. It provides a unified control plane for consistent API policy, security, and analytics while supporting visual API proxy mapping, drag-and-drop policy management, and a customizable developer portal to accelerate API adoption and reuse. Bijira leverages AI tools to help generate OpenAPI specs, test APIs using natural language prompts, validate compliance with governance rules, and feed insights back into the API development process. It integrates robust security mechanisms, including OAuth2, OIDC, fine-grained access control, and firewall protections, and enforces governance-as-code with AI-assisted policy validation.
