Closed SourceOpenAIReleased 2026-04

GPT-5.5

OpenAI's stepping revision between GPT-5 and the next generation - better instruction following, same price class as GPT-4o

Context window

128K

Input / 1M tokens

Free

Output / 1M tokens

Free

Provider

OpenAI

Positioned at a similar price point to GPT-4o. GPT-5.5 Pro is a higher-cost tier for enterprise agentic workloads.

GPT-5.5 fills the gap between GPT-4o and GPT-5 in OpenAI's lineup. It offers improved instruction following and stronger long-context behavior at a price point closer to GPT-4o than GPT-5. A GPT-5.5 Pro variant targets higher-stakes production workloads where output consistency across parallel agentic calls is the failure mode.

Strengths

  • Improved instruction following over GPT-4o
  • Stronger long-context coherence
  • Better output consistency for agentic pipelines
  • GPT-5.5 Pro tier for reliability-critical workloads
  • Easier migration path than jumping from GPT-4o to GPT-5

Best for developers who...

Production API integrations migrating from GPT-4oAgentic workflows needing consistent structured outputLong-context document tasksTeams deferring full GPT-5 migration costs

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