Blog
ChatGPT 5.5 Ultra & Codex API guides
Migration tutorials, Cursor setup, and pricing explainers for teams moving to flat OpenAI-compatible API access.
API checklist
OpenAI-Compatible API Pre-Buy Testing Checklist
A practical pre-buy checklist for testing /models, chat, embeddings, images, custom base URLs, model IDs, retries, and concurrency before choosing a provider.
7 min read - Updated 2026-07-12
API checklist
OpenAI-Compatible API Provider Checklist for Coding Agents
A practical checklist for testing custom base URLs, model IDs, chat/completions, embeddings, image generation, retries, and concurrency before using any OpenAI-compatible provider.
8 min read - Updated 2026-07-12
Migration
How to Migrate from OpenAI API to unlimitedcodex
Swap base URL and API key, keep your OpenAI-compatible SDK code, and move ChatGPT 5.5 Ultra and Codex workloads to flat weekly or monthly access.
6 min read - Updated 2026-07-12
Integrations
Point Cursor at a Custom OpenAI-Compatible Base URL
Configure Cursor with your delivered unlimitedcodex base URL and API key for ChatGPT 5.5 Ultra and Codex coding workflows.
5 min read - Updated 2026-07-12
Pricing
ChatGPT 5.5 Ultra API Pricing: Per-Token vs Flat Access
Compare metered OpenAI-style billing against unlimitedcodex weekly and monthly packages for heavy ChatGPT 5.5 Ultra and Codex usage.
7 min read - Updated 2026-07-12