Changelog

All notable changes to the Nellie API will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Planned

  • Additional output formats
  • Custom chapter length controls
  • Multi-language content generation
  • Batch generation endpoint

[1.0.0] - 2025-12-01

Added

Core API

  • POST /v1/book — Asynchronous book generation endpoint

    • Support for 30+ genres/styles
    • 9 output types (novel, comic, manga, etc.)
    • 6 export formats (txt, pdf, epub, md, html, json)
    • AI image generation option
    • Custom author attribution
    • Custom tone guidance
    • Webhook callback support

  • GET /v1/status/{requestId} — Job status polling endpoint

    • Real-time progress percentage
    • Status messages log
    • Result URL on completion
    • Credit usage tracking

  • GET /v1/configuration — Configuration options endpoint

    • Available styles list
    • Available types list
    • Available output formats list

  • GET /v1/models — Available models endpoint

    • Model descriptions
    • Cost per generation

  • GET /v1/usage — Usage statistics endpoint

    • Total requests count
    • Total credits consumed
    • Recent request history

Authentication

  • API key authentication via X-API-Key header
  • Key format: nel_ prefix
  • Key management in Nellie app dashboard

Webhooks

  • Webhook notifications on job completion
  • HMAC-SHA256 signature verification
  • X-Nellie-Signature header with timestamp
  • Replay attack protection (5-minute window)
  • Automatic retry on failure (3 attempts)

AI Models

  • Nellie 2.0 (Standard) — 250 credits, balanced performance
  • Nellie 3.0 (Premium) — 500 credits, enhanced creativity

Rate Limiting

  • Burst limit: 1 request per 6 seconds
  • Daily limit: 15 requests per API key
  • Transactional enforcement in Firestore

SDK

  • Official Python SDK nellie-api
  • Type hints and dataclasses
  • Automatic retry with exponential backoff
  • Webhook signature verification utilities
  • Wait-for-completion polling helper

Security

  • SSRF protection for webhook URLs
  • Webhook signature verification
  • API key rotation support
  • Environment variable configuration

Documentation

  • API Quick Start Guide
  • Full API Documentation
  • Python SDK Reference
  • Webhook Integration Guide
  • Error Reference
  • Rate Limits Guide
  • Best Practices

Version History Summary

VersionDateHighlights
1.0.0Dec 2025Initial public release

Upgrade Notes

Upgrading to 1.0.0

This is the initial release. No upgrade steps required.

For users of the beta/preview API:

  1. Update base URL to https://api.nelliewriter.com/v1
  2. Ensure all endpoints use /v1/ prefix
  3. Update SDK to version 0.1.0+
  4. Review rate limits (may have changed from beta)

Versioning Policy

API Versioning

  • Major versions (/v1/, /v2/) indicate breaking changes
  • Minor updates are backward compatible within a version
  • Deprecated features have minimum 6-month sunset period
  • Version in URL path (not headers)

SDK Versioning

  • Follows Semantic Versioning
  • Major: Breaking API changes
  • Minor: New features, backward compatible
  • Patch: Bug fixes, backward compatible

Deprecation Process

  1. Announcement — Feature marked deprecated in docs
  2. Warning — Response headers include deprecation warnings
  3. Sunset — Feature removed after announced date