How is the version bump chosen?

Any breaking change suggests a major bump, additive-only changes suggest a minor bump, and documentation-only edits suggest a patch.

Can I edit the output?

Yes, copy the Markdown and adapt it for your release notes.

Does it send my specs to a server?

No, the diff runs entirely in your browser.

Does it work offline and on mobile?

Yes. Once the page has loaded it keeps working without a network connection, and the layout is responsive so it stays usable on phones and tablets.

Do I need an account or an API key?

No. Every tool on Coders Hub is free to use with no sign-up, no API key and no usage limits.

API Changelog Generator

Generate a Markdown changelog from two OpenAPI versions.

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Release date

Auto semver bump

Migration guide

Previous spec

openapi: 3.0.3
info:
  title: Orders API
  version: 1.2.0
paths:
  /orders:
    get:
      operationId: listOrders
      summary: List orders
      tags: [orders]
      parameters:
        - name: limit
          in: query
          required: false
          schema:
            type: integer
      responses:
        "200":
          description: OK
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
                  required: [id, total]
                  properties:
                    id:
                      type: string
                    total:
                      type: number
    post:
      operationId: createOrder
      summary: Create an order
      tags: [orders]
      responses:
        "201":
          description: Created
  /orders/{orderId}:
    get:
      operationId: getOrder
      summary: Get an order
      tags: [orders]
      parameters:
        - name: orderId
          in: path
          required: true
          schema:
            type: string
      responses:
        "200":
          description: OK
        "404":
          description: Not found

Current spec

openapi: 3.0.3
info:
  title: Orders API
  version: 1.3.0
paths:
  /orders:
    get:
      operationId: listOrders
      summary: List orders
      tags: [orders]
      parameters:
        - name: limit
          in: query
          required: false
          schema:
            type: integer
        - name: status
          in: query
          required: true
          schema:
            type: string
      responses:
        "200":
          description: OK
          content:
            application/json:
              schema:
                type: array
                items:
                  type: object
                  required: [id, total, currency]
                  properties:
                    id:
                      type: string
                    total:
                      type: string
                    currency:
                      type: string
    post:
      operationId: createOrder
      summary: Create an order
      tags: [orders]
      responses:
        "201":
          description: Created
  /orders/{orderId}:
    get:
      operationId: getOrder
      summary: Get an order
      tags: [orders]
      parameters:
        - name: orderId
          in: path
          required: true
          schema:
            type: string
      responses:
        "200":
          description: OK
  /refunds:
    post:
      operationId: createRefund
      summary: Create a refund
      tags: [refunds]
      responses:
        "201":
          description: Created

Generated changelog

Markdown ready to paste into CHANGELOG.md or release notes

Breaking

Risky

Added

Suggested bump

major

# Orders API changelog

## 2.0.0 — 2026-08-20

_Compared against 1.2.0. 3 breaking, 0 risky, 1 additive changes._

> **Heads up:** this release contains breaking changes. Bump the major version and notify integrators before deploying.

### Breaking changes

- **GET /orders** — New required query parameter `status` — existing callers will fail.
- **GET /orders** — Response `200 application/json` schema changed.
- **GET /orders/{orderId}** — Response `404` removed.

### Added

- **POST /refunds** — New operation added.

### Migration guide

1. `GET /orders` — New required query parameter `status` — existing callers will fail.
2. `GET /orders` — Response `200 application/json` schema changed.
3. `GET /orders/{orderId}` — Response `404` removed.

About the API Changelog Generator

Diff two OpenAPI documents and produce a release-ready Markdown changelog grouped into Breaking Changes, Added, Changed and Removed, complete with a suggested semantic version bump you can paste straight into release notes or docs.

Examples

v1 → v2

Two OpenAPI documents

Output

## Breaking Changes
- Removed `DELETE /users/{id}`

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-20 · Runs entirely in your browser