GPT-5.6 Blog

GPT-5.6 Release Date, Features & Development: What Developers Need to Know
May 17, 2026
GPT-5.6

GPT-5.6 Release Date, Features & Development: What Developers Need to Know

GPT-5.6 is already in internal testing just weeks after GPT-5.5's April 23, 2026 launch. Expected release as early as June 2026, with potential UltraFast Codex mode, expanded context (up to 1.5M tokens in tests), and intensified competition against Claude Code. Discover benchmarks, leaks (ember-alpha, beacon-alpha), and how CometAPI delivers cost-effective access to GPT-5.5 and alternatives today.