API Collection Generator

Generate Postman-compatible API collections from Swagger / OpenAPI documentation.
Designed for NestJS applications but works with any OpenAPI 3.x / Swagger 2.0 spec.

Features

• All HTTP methods – GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS
• Request bodies – application/json, multipart/form-data, application/x-www-form-urlencoded, text/plain, application/xml
• Path parameters – {id} → Postman :id format with sample values
• Query parameters – extracted from Swagger with descriptions and required flags
• Header parameters – custom headers from Swagger spec
• Authentication – Bearer token, Basic auth, API Key (header/query), OAuth2, OpenID Connect
• Schema resolution – full $ref, allOf, oneOf, anyOf support with sample generation
• Response examples – auto-generated response bodies from schemas
• Folder grouping – by Swagger tags (default) or first path segment
• Configurable – base URL, output path, collection name, and more
• Collection variables – {{base_url}}, {{access_token}}, {{api_key}}, etc.

Installation

npm install api-collections-generator

Usage (NestJS)

Basic

import GenerateAPICollection from "api-collections-generator";
import { DocumentBuilder, SwaggerModule } from "@nestjs/swagger";

const config = new DocumentBuilder()
  .setTitle("Your API")
  .setDescription("API description")
  .setVersion("1.0")
  .addBearerAuth()
  .build();

const document = SwaggerModule.createDocument(app, config);
SwaggerModule.setup("api", app, document);

const generator = new GenerateAPICollection(document);
generator.generateAPICollection();
// → writes collection.json to your project root

With Options

const generator = new GenerateAPICollection(document, {
  baseUrl: "http://localhost:4000", // default: "http://localhost:3000"
  outputPath: "postman/my-api.json", // default: "collection.json"
  collectionName: "My Service API", // default: extracted from Swagger info.title
  groupByTags: true, // default: true (false = group by path segment)
  includeResponses: true, // default: true
});
generator.generateAPICollection();

Options Reference

| Option | Type | Default | Description | | ------------------ | --------- | ------------------------- | -------------------------------------------- | | baseUrl | string | "http://localhost:3000" | Base URL prepended to every request | | outputPath | string | "collection.json" | Output file path relative to process.cwd() | | collectionName | string | Swagger info.title | Name shown in Postman | | groupByTags | boolean | true | Group requests into folders by Swagger tags | | includeResponses | boolean | true | Include example responses in collection |

Output

A Postman Collection v2.1.0 JSON file importable via Postman → Import → Raw text / File.

The collection includes:

• Folders organised by tag (or path)
• Pre-filled request bodies with realistic sample values
• Path and query parameters with descriptions
• Auth headers derived from your Swagger security schemes
• Collection-level variables for easy environment switching

Supported Swagger / OpenAPI Features

| Feature | Support | | --------------------------------- | -------------------------------------- | | OpenAPI 3.x paths | Yes | | Swagger 2.0 paths | Yes | | $ref schema references | Yes (recursive) | | allOf / oneOf / anyOf | Yes | | enum values | Yes (first value used) | | example / default values | Yes | | Nested objects & arrays | Yes | | File uploads (binary) | Yes (form-data) | | Security schemes | Bearer, Basic, API Key, OAuth2, OpenID | | Global & operation-level security | Yes | | Tags-based grouping | Yes | | Path-level parameters | Yes |

License

ISC