Generating documentation from collections in Postman - Build an Automation Script

Generate API documentation from a Postman collection

Preconditions (2)

Step 1: Open Postman application or web version

Step 2: Navigate to the Collections tab

Step 3: Select the desired collection to document

Step 4: Click on the '...' (three dots) menu next to the collection name

Step 5: Choose 'Publish Docs' from the dropdown menu

Step 6: In the documentation editor, verify the collection name and description

Step 7: Review the automatically generated documentation for each request

Step 8: Click 'Publish' to generate a public documentation link

Step 9: Copy the generated documentation URL

✅ Expected Result: A public documentation page is created and accessible via the copied URL, showing all requests and details from the selected collection

Automation Requirements - Postman Test Scripts and Newman CLI

Assertions Needed:

Verify the collection exists and is accessible

Verify the documentation generation command runs without errors

Verify the generated documentation URL is not empty

Verify the documentation page contains the collection name

Best Practices:

Use Newman CLI to run collection and generate documentation

Use environment variables for collection and documentation URLs

Validate outputs with assertions in test scripts

Use explicit checks for HTTP response codes when accessing documentation URL

Automated Solution

Postman

import newman from 'newman';

// Run the collection and generate documentation
newman.run({
    collection: './MyCollection.json',
    reporters: ['cli', 'html'],
    reporter: {
        html: {
            export: './docs/collection-documentation.html'
        }
    }
}, function (err, summary) {
    if (err) {
        console.error('Collection run failed:', err);
        process.exit(1);
    }
    // Check if run was successful
    const runStats = summary.run.stats;
    if (runStats.failed > 0) {
        console.error(`Test failures: ${runStats.failed}`);
        process.exit(1);
    }
    console.log('Collection run completed successfully. Documentation generated at ./docs/collection-documentation.html');
});

This script uses Newman, the command-line runner for Postman collections, to run the collection and generate an HTML report which serves as documentation.

The collection option points to the local Postman collection file.

The reporters option includes html to generate a documentation page.

The reporter.html.export option specifies the output file path for the documentation.

After running, the script checks for errors and test failures, logging appropriate messages.

This approach automates documentation generation and verifies the collection runs without errors.

Common Mistakes - 3 Pitfalls

Not specifying the collection file path correctly in Newman run

Not checking for errors or failed tests after running the collection

Assuming documentation URL is generated automatically without publishing

Bonus Challenge

Now add data-driven testing by running the collection with 3 different environment files

Show Hint

Practice

1. What is the main benefit of generating documentation from Postman collections?

easy

A. It only works for public APIs, not private ones.

B. It requires manual writing of all API details.

C. It saves time and reduces errors by automating documentation.

D. It replaces the need for testing APIs.

Solution

1. Step 1: Understand the purpose of documentation generation

   Generating docs from collections automates the process, reducing manual work and mistakes.

2. Step 2: Compare options with this purpose

   Only It saves time and reduces errors by automating documentation. correctly states the benefit of saving time and reducing errors.

3. Final Answer:

   It saves time and reduces errors by automating documentation. -> Option C

4. Quick Check:

   Automation saves time and errors [OK]

Hint: Remember: automation reduces manual errors and saves time [OK]

Common Mistakes:

• Thinking documentation must be written manually
• Believing docs replace API testing
• Assuming docs only work for public APIs

2. Which Postman feature allows you to add explanations to each API request for better documentation?

easy

A. Pre-request scripts

B. Environment variables

C. Test scripts

D. Request descriptions

Solution

1. Step 1: Identify how to add explanations in Postman

   Request descriptions let you write notes or explanations for each API request.

2. Step 2: Match options to this feature

   Only 'Request descriptions' directly relate to adding explanations for documentation.

3. Final Answer:

   Request descriptions -> Option D

4. Quick Check:

   Descriptions explain requests [OK]

Hint: Descriptions add notes to requests for docs [OK]

Common Mistakes:

• Confusing test scripts with documentation notes
• Using environment variables for explanations
• Thinking pre-request scripts add descriptions

3. Given a Postman collection with detailed request descriptions, what will happen when you generate documentation from it?

medium

A. The documentation will include the request descriptions automatically.

B. Descriptions must be added manually after generating docs.

C. Only request names appear; descriptions are ignored.

D. Documentation cannot be generated from collections.

Solution

1. Step 1: Understand how Postman uses request descriptions

   Postman includes request descriptions automatically in generated documentation.

2. Step 2: Evaluate each option

   The documentation will include the request descriptions automatically. correctly states that descriptions appear automatically; others are incorrect.

3. Final Answer:

   The documentation will include the request descriptions automatically. -> Option A

4. Quick Check:

   Descriptions auto-included in docs [OK]

Hint: Descriptions appear automatically in generated docs [OK]

Common Mistakes:

• Assuming manual addition of descriptions after generation
• Thinking descriptions are ignored
• Believing docs can't be generated from collections

4. You tried to publish documentation from a Postman collection, but the descriptions are missing. What is the most likely cause?

medium

A. Descriptions were not added to the requests before publishing.

B. The collection was not saved before publishing.

C. Postman does not support publishing documentation.

D. You need to write descriptions in test scripts.

Solution

1. Step 1: Identify why descriptions might be missing

   If descriptions are missing, likely they were never added to requests.

2. Step 2: Check other options for correctness

   Saving collection is important but usually does not remove descriptions; Postman supports publishing; test scripts do not hold descriptions.

3. Final Answer:

   Descriptions were not added to the requests before publishing. -> Option A

4. Quick Check:

   Missing descriptions mean none were added [OK]

Hint: Add descriptions before publishing docs [OK]

Common Mistakes:

• Forgetting to add descriptions before publishing
• Confusing test scripts with descriptions
• Thinking Postman can't publish docs

5. You want to share your API documentation with your team and keep it updated automatically when the collection changes. What is the best way to do this in Postman?

hard

A. Export the collection as JSON and email it to the team.

B. Publish the documentation from the collection and share the published link.

C. Copy and paste the collection details into a Word document.

D. Take screenshots of the collection and share images.

Solution

1. Step 1: Identify how to share and keep docs updated

   Publishing documentation creates a live link that updates automatically with collection changes.

2. Step 2: Evaluate other options

   Exporting JSON or copying details are manual and do not update automatically; screenshots are static.

3. Final Answer:

   Publish the documentation from the collection and share the published link. -> Option B

4. Quick Check:

   Published docs auto-update and share easily [OK]

Hint: Use published docs link for auto-updated sharing [OK]

Common Mistakes:

• Sharing static files instead of live docs
• Assuming exported JSON is readable documentation
• Using screenshots which do not update