OpenAPI

Speakeasy OpenAPI Editor vs Swagger Editor vs Postman

Nolan Di Mare Sullivan

October 27, 2025 - 8 min read

OpenAPI

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You’re designing a new API endpoint. You need to generate the OpenAPI document, validate it against the required standards, collaborate with your team on the design, and keep it synchronized with your codebase as the API evolves.

In this guide, we’ll compare three popular OpenAPI editors: Speakeasy OpenAPI Editor, Swagger Editor , and Postman . We’ll evaluate them based on what matters most when maintaining API specifications: editing experience, validation capabilities, workflow integration, and their fit within your broader API toolchain.

OpenAPI document editing experience

All three editors provide a familiar VSCode-like interface for authoring OpenAPI documents. The main difference lies in the depth of feedback and error detection they offer.

Validation and error detection

All three editors offer real-time validation, but the quality and depth of feedback vary based on the level of detail and help provided to address that feedback. Speakeasy provides the most comprehensive validation system, featuring three levels of feedback:

• Errors: Specification violations that must be fixed.

• Warnings: Potential issues or best practices you’re breaking that won’t cause errors but may cause problems downstream.

• Hints: Suggestions for improving specification quality, like adding examples to parameters. For example, Speakeasy’s hints might suggest:

  • Adding example values to request parameters.
  • Including response descriptions for all status codes.
  • Defining reusable components for repeated schemas.

  These suggestions enhance specification quality even when the document is technically valid.

This tiered approach helps you understand not just what’s broken but what could be better. Speakeasy also includes a dedicated panel that lists all warnings, hints, and errors for easy navigation.

For production APIs, this validation depth matters. While live previews show what the API documentation will look like, comprehensive validation catches issues that could break your SDK generation, cause integration problems, or create confusion for API consumers. It’s the difference between “Does this look right?” and “Is this OpenAPI document actually correct and complete?”.

Swagger Editor shows detailed error messages when you violate the OpenAPI specification but lacks the nuanced warnings or hints that help improve spec quality beyond basic correctness.

Postman also displays detailed error information when validation fails, focusing on specification compliance.

Live preview

Both Swagger Editor and Postman offer live preview capabilities. Swagger displays a full Swagger UI rendering of your API documentation, offering a consumer-facing view of your spec.

Postman provides a more developer-oriented preview that shows individual OpenAPI components as you edit them. For instance, when working on a path, you’ll see that component’s properties rendered in the preview pane.

Autocomplete

Currently, only Postman provides autocomplete functionality, helping you write OpenAPI documents faster by suggesting valid OpenAPI properties and values as you type.

Specification fidelity

All three editors support OpenAPI 3.x specifications and handle complex schemas, components, and syntax without issues. However, they diverge in their treatment of custom extensions.

Extension support

OpenAPI specifications allow for custom extensions (properties prefixed with x-) that teams use to add vendor-specific functionality or metadata to their OpenAPI documents.

Speakeasy fully understands and validates custom extensions, which means you get proper validation, autocomplete, and documentation for your custom x- properties, treating them as first-class citizens in your specification.

Swagger Editor and Postman accept custom extensions without throwing errors, but they don’t provide any special handling, validation, or tooling support for them. Instead, the extensions are passed through as unknown properties.

Workflow integration

How an OpenAPI editor fits into your development workflow can make the difference between a tool that streamlines your process and one that creates friction.

Version control

Speakeasy is built around a Git-based version control model. Every change is automatically committed with a hash, giving you a complete file history that you can navigate.

Speakeasy’s Git-based model means every edit creates a commit automatically, which allows you to:

• Review the complete change history with commit hashes.
• Roll back to any previous version.

You can see exactly what changed and when, and publish your OpenAPI document either to the main branch or as a custom tag. This automatic versioning preserves your OpenAPI document’s changes history without any manual effort.

The free Swagger Editor doesn’t include version control, which means your work is stored in the browser cache and can be lost when you clear it. However, SwaggerHub (the commercial platform) provides versioning capabilities where you can manually register versions, though it doesn’t automatically create commits like Speakeasy.

Postman does not provide built-in versioning for your OpenAPI documents. Version tracking only occurs when you update the version field in your document and sync it with collections.

CI/CD capabilities

Speakeasy excels in CI/CD integration. Publishing a new version to the main branch or creating a custom tag can automatically trigger downstream processes, such as generating new SDKs, updating MCP servers, or refreshing Terraform providers. This tight integration keeps your entire API toolchain synchronized with your OpenAPI document changes.

The free Swagger Editor lacks CI/CD integration. SwaggerHub provides webhooks that fire with each new version, allowing teams to write custom scripts to handle these webhooks and trigger downstream processes like SDK regeneration or documentation updates.

Postman does not provide any workflow integration or automation capabilities.

Export and portability

Speakeasy allows you to download your entire workspace as a ZIP file, including the OpenAPI document, overlays, and workflow files that define how the Speakeasy CLI combines overlays with your base specification. Speakeasy’s overlay  support allows teams to modify OpenAPI documents without touching the source file. For example, you might add vendor-specific extensions or customize descriptions for different audiences while keeping the base specification unchanged. The workflow file defines how overlays combine with the base OpenAPI document.

Swagger Editor supports exporting your OpenAPI document in either JSON or YAML format.

Postman does not offer a dedicated export feature for OpenAPI specifications from the Specs editor.

Ecosystem and integration

OpenAPI editors differ in how they integrate with SDK generation and API tooling.

SDK generation

Speakeasy and Swagger Editor both offer SDK generation from your OpenAPI specification. Speakeasy specializes in SDK generation as its core product. It supports eight languages  and generates production-ready SDKs with:

• Type safety and navigable structure.
• Comprehensive documentation.
• OAuth2, retries, and pagination support.
• Webhook handling.
• Idiomatic code that feels natural to developers in each language.
• Extensibility and batteries-included features.

The Editor integrates directly with this generation pipeline, providing validation and hints specifically designed to improve SDK quality.

Swagger Editor uses swagger-codegen  under the hood, which presents some challenges:

• Some unresolved bugs: Over 3k open issues  as of October 2025.
• Inconsistent API feature coverage: Struggles with OAuth, union types, and pagination in moderately complex APIs.
• Non-idiomatic code: Originally a Java-based project, the generated code often feels Java-like, even in languages like Python or TypeScript, which can be off-putting for developers.

Postman does not offer SDK generation capabilities.

MCP servers

MCP (Model Context Protocol) servers allow users to interact with your APIs through LLMs, which is an increasingly essential capability as AI integration becomes standard.

Swagger Editor enables the generation of MCP servers with streamable transports, but you are responsible for hosting, running, and maintaining them. Distribution typically happens via ZIP files or GitHub repositories with manual installation instructions for users.

Speakeasy generates both local and remote MCP servers from your OpenAPI document. Within the Speakeasy Editor, you can visualize the artifacts for the MCP server along with the accepted parameters for each tool.

Combined with Speakeasy’s CI/CD integration, you can automatically update these MCP servers whenever your OpenAPI document changes, no manual code updates required.

Postman does not offer MCP server generation.

Pricing and accessibility

Swagger Editor  is completely free and open source, while Swagger Pro  ($9/month) adds code generation and API versioning. For team collaboration and CI/CD integrations like webhooks, API Hub  offers plans starting at $29/month for teams and $49/month for enterprises.

Speakeasy provides its OpenAPI Editor as part of the Starter plan, which includes unlimited APIs with one SDK target.

Postman offers the Spec editor free of charge.

Which tool to use?

The right OpenAPI editor depends on your team’s workflow and priorities:

• If you are looking for superior validation to ensure that your OpenAPI document is of top-tier quality and to make the creation of OpenAPI documentation, SDKs, or MCP server generation easier, then choose Speakeasy.
• If you want to preview your UI without relying on generating tools from your OpenAPI document, the Swagger Editor is sufficient.
• If the UI preview of your API doc in Swagger UI isn’t essential, then Postman is a good option.

Final thoughts

Swagger Editor and Postman are great tools that set the standard for OpenAPI editing. At Speakeasy, our goal is to go far beyond those standards with a platform that’s better for designing, validating, and managing your APIs end to end. Try it for yourself and experience the difference.