According to Postman’s 2024 State of the API Report, over 30 million developers across the globe rely on APIs daily and Postman alone is used by 25 million of them. Meanwhile, Swagger (part of the OpenAPI ecosystem) powers over 40% of public API documentation across industries, according to SmartBear’s usage data.
While both Postman and Swagger support the API lifecycle, they were built with different goals in mind.
In this blog, we will dive deep into Swagger vs Postman, comparing their features, ideal use cases, and how they complement (or compete with) each other in a modern API workflow.
What is Swagger?
Swagger is a suite of open-source and commercial tools designed for API design, documentation, and testing. At its core is the OpenAPI Specification (formerly known as Swagger Specification), which has become the industry standard for describing RESTful APIs in a machine-readable format (JSON or YAML).
Primary Use Cases:
- API documentation tools for developers and consumers.
- API schema validation and code generation.
- Mock servers for early development and testing.
Security Note: Swagger’s alignment with OpenAPI ensures strong support for API security best practices, including authentication, authorization, and schema validation (see OWASP API Security Top 10).
What is Postman?
Postman is a comprehensive API platform focused on API testing, automation, and collaboration. It enables teams to design, test, monitor, and document APIs within a unified workspace.
Key Postman Features:
- Postman Workspace: Central hub for API collections, environments, and team collaboration.
- Newman: Command-line runner for automated API testing and CI/CD integration.
- Mock servers: Simulate API endpoints for development and testing.
- API monitoring: Automated uptime and performance checks.
- API documentation: Auto-generates docs from collections.
Primary Use Cases:
- Manual and automated API testing.
- API lifecycle management and monitoring.
- Team-based API collaboration and versioning.
Security Note: Postman supports advanced authentication flows (OAuth, JWT, API keys) and integrates with security testing workflows (see NIST API Security Guidelines).
Swagger vs Postman: Feature-by-Feature Comparison
| Feature | Swagger (OpenAPI) | Postman |
|---|---|---|
| Primary Use | API design and documentation | API testing, debugging, and monitoring |
| Approach | API-first (define before build) | Test-driven (use existing API to test/use) |
| Specification Support | Native OpenAPI support | Supports OpenAPI import/export |
| Visualization | Swagger UI for auto-generated docs | Clean, shareable documentation tools |
| Code Generation | Yes – via Swagger Codegen or OpenAPI tools | Limited – uses snippets and code samples |
| Automation | Limited; relies on external tools/scripts | Built-in test automation with JavaScript |
| Mocking | Available with SwaggerHub | Built-in mock servers |
| Monitoring | Requires integration | Native monitoring and alerting |
| Collaboration | SwaggerHub for teams | Built-in workspaces, versioning, comments |
| Ease of Use | Requires some learning curve (YAML/JSON) | Very user-friendly GUI |
| Cost | Open-source (Swagger tools); Paid (Hub) | Free tier + Premium options |
Use Case Scenarios: When to Use Swagger vs Postman
Use Swagger If…
- You are building an API from scratch (API-first approach)
Swagger (via OpenAPI specifications) is ideal when your team starts by defining how the API should behave before writing any code. This helps back-end and front-end teams work in parallel and reduces rework. - You want to ensure contract consistency across teams
With Swagger, once the API spec is agreed upon, it becomes the single source of truth. This makes collaboration between developers, testers, and third-party consumers more reliable and consistent. - You need automatic code generation
Swagger Codegen and OpenAPI Generator can create server stubs and client SDKs in various programming languages based on the spec. This speeds up development and ensures adherence to the API design. - You need to auto-generate interactive API documentation
Swagger UI turns your API spec into live, interactive documentation. This makes it easy for internal and external developers to understand and test endpoints. - You are publishing APIs as a product
API publishers often rely on SwaggerHub to design, manage, and document public APIs in a collaborative environment.
Use Postman IF
- You are testing existing APIs
Postman is perfect for consuming APIs that are already built. You can send HTTP requests, test responses, and explore how the API behaves under various conditions. - You want to automate test cases for APIs
With Postman’s scripting capabilities (using JavaScript), you can write pre-request scripts, tests, and even create CI/CD test pipelines with Newman (Postman’s CLI). - You need to mock APIs before the backend is ready
Postman lets you create mock servers from saved examples, allowing front-end developers to continue development even if the back-end logic is not live yet. - You require monitoring and alerts
Postman monitors allow you to run collections at scheduled intervals, check response times, status codes, and get alerted when something goes wrong. - You collaborate across large QA, Dev, or Product teams
Workspaces, version control, commenting, and sharing collections make Postman a powerful collaboration platform, especially for distributed teams.
Swagger vs Postman: Pros and Cons
Swagger (OpenAPI / SwaggerHub)
Pros:
- API-first approach
Encourages design consistency and clean architecture by starting with a contract before implementation. - OpenAPI compliance
Ensures standardized API documentation and interoperability across tools and systems. - Automated code generation
Reduces manual effort by generating server stubs and SDKs in over 40 programming languages. - Interactive, auto-updating documentation
Swagger UI provides a live view of the API that updates as the spec changes. - Centralized platform with SwaggerHub
Teams can collaboratively design, publish, and version APIs with governance features.
Cons:
- Steeper learning curve
Requires understanding OpenAPI YAML/JSON syntax and workflows. - Not built for manual testing
Swagger tools do not support request chaining, assertions, or automation out of the box. - Limited mock and monitoring capabilities
Requires additional integrations for advanced testing or monitoring pipelines.
Postman
Pros:
- User-friendly interface
Even non-developers can test APIs using Postman’s intuitive GUI. - Powerful test scripting and automation
Built-in JavaScript-based test framework allows you to validate API behavior quickly. - Built-in mock servers
Mock endpoints allow for rapid prototyping and frontend/backend decoupling. - Monitoring and performance insights
Track uptime, response time, and get failure alerts easily. - Seamless collaboration
Shared workspaces, environments, and collections support team-wide development and QA workflows. - CI/CD integration with Newman
Collections can be run via command line and integrated into Jenkins, GitHub Actions, etc.
Cons:
- Not ideal for API design
You can import OpenAPI specs but designing them from scratch is not as structured or robust as Swagger. - Some features are gated in paid plans
Advanced features like enhanced monitoring, custom domains, and team-level governance may require paid tiers. - Can become cluttered for large-scale API projects
Managing hundreds of collections and environments can become difficult without strict organization.
How to Use Swagger for API Documentation
Step 1: Set Up Swagger Tools
Swagger provides several tools:
- Swagger Editor – For writing and editing OpenAPI (Swagger) definitions.
- Swagger UI – For visually browsing API documentation.
- SwaggerHub – A cloud-based platform for team collaboration.
Step 2: Write Your API Definition
You can define your API using YAML or JSON formats. Here’s a basic example in YAML:
openapi: 3.0.0
info:
title: User API
version: 1.0.0
paths:
/users:
get:
summary: Get all users
responses:
‘200’:
description: A list of users
This defines a simple GET request to /users.
Step 3: Add More Details
Enhance your documentation by including:
- Parameters (query, path, header)
- Request body (with JSON schema)
- Responses (status codes, example outputs)
- Authentication methods (API keys, OAuth)
/users/{id}:
get:
summary: Get user by ID
parameters:
– name: id
in: path
required: true
schema:
type: integer
responses:
‘200’:
description: User data
‘404’:
description: User not found
4: View Documentation with Swagger UI
To visualize your API:
- Host your YAML/JSON on a server.
- Use Swagger UI to render a beautiful, interactive interface.
- Developers can try out endpoints directly from the browser.
5: Share or Collaborate (Optional)
If you are working with a team:
- Use SwaggerHub to manage API versions, collaborate, and generate client/server code.
- Enable comments, roles, and version control.
Bonus: Generate Server and Client Code
Swagger supports automatic code generation:
- Use tools like Swagger Codegen or OpenAPI Generator
- Generate client SDKs or server stubs in languages like Python, Java, Node.js, etc.
How to Use Postman for API Testing
1: Install and Launch Postman
- Download Postman from: https://www.postman.com/downloads/
- Install and sign up or log in.
- You can also use the Postman Web version if you prefer not to install it.
2: Create a New Request
- Click on “+ New Tab” or the “New” button.
- Select Request.
- Choose your HTTP method (GET, POST, PUT, DELETE, etc.).
- Enter the API URL in the request field.
- Click Send to make the request.
3: Add Parameters and Headers (Optional)
- Use the Params tab to add query parameters (e.g., ?id=123).
- Use the Headers tab to add custom headers (e.g., Authorization, Content-Type).
- Use the Body tab (for POST, PUT, PATCH) to add JSON, form-data, or raw text as the request payload.
4: Inspect the Response
Once you click Send, Postman displays:
- Status code (e.g., 200 OK, 404 Not Found)
- Response body (JSON, XML, HTML, etc.)
- Time taken and response size
- Cookies and headers returned by the API
5: Save and Organize Requests
- Save your request to a Collection for future use.
- Collections help you group related API requests (e.g., User APIs, Product APIs).
- Add descriptions, variables, or scripts to each request for better documentation.
6: Use Tests and Automation
Postman supports JavaScript-based test scripts. You can:
- Validate status codes
- Check response values
- Set environment variables
You can also run multiple requests using the Collection Runner or Newman CLI for automated testing.
7: Use Environments and Variables
Postman lets you define environments (e.g., Dev, QA, Prod) and variables like:
- {{base_url}}
- {{auth_token}}
Switch environments to easily test the same request on different servers.
AppTrana’s API Protection: Built Around Swagger and Postman
AppTrana’s API protection is purpose-built to align with how modern teams work, using both Postman and Swagger (OpenAPI) files to drive accurate security assessments and tailored protections. During onboarding, customers can upload Postman collections, which contain detailed information about API endpoints, parameters, dynamic values, and request flows. This helps AppTrana simulate real usage patterns during vulnerability scans. These scans are further enriched by expert intervention to eliminate false positives and ensure a clear view of the APIs’ risk posture.
Simultaneously, Swagger files are used to automatically create positive security policies that enforce strict schema validation and input filtering, significantly reducing the API’s attack surface. For organizations that lack up-to-date API documentation, AppTrana can automatically discover existing, shadow, zombie, and rogue APIs and generate a complete OpenAPI 2.0 (Swagger) specification file with pre-filled details. This not only improves visibility but also enables continuous protection through behavior-based DDoS policies, bot detection, and schema-aware traffic enforcement, ensuring APIs are both secure and compliant from the ground up.
Ready to secure your APIs across the lifecycle?
Explore Indusface’s API Security Solutions or request a demo to see how we help global enterprises protect their digital assets.
