GPT-5.5 - OpenAI's Most Capable Coding Model

GPT-5.5 is OpenAI's most capable coding model. It improves on GPT-5.4 across every major benchmark — agentic coding, terminal workflows, math, and computer use — while keeping the 1M-token context window that makes it effective for large, complex projects.

Why Choose GPT-5.5 for Your Agent?

Stronger benchmarks on everything that matters for building web apps:

• 82.7% on Terminal-Bench 2.0 — up from 75.1% on GPT-5.4. More reliable multi-step terminal workflows, fewer broken sequences
• 58.6% on SWE-Bench Pro — top-tier real-world software engineering performance
• 84.9% on GDPval — professional knowledge work quality (up from 83.0%)
• 78.7% on OSWorld-Verified — best-in-class computer use and navigation
• 1M-token context window — holds large codebases in view across cross-file refactors and long sessions
• 35.4% on FrontierMath Tier 4 — sharply up from 27.1%, meaning significantly better reasoning on hard problems

What developers say:

"The first coding model I've used that has serious conceptual clarity." — Dan Shipper, Every

"Losing access to GPT-5.5 feels like I've had a limb amputated." — Engineer at NVIDIA

"GPT-5.5 is noticeably smarter and more persistent than GPT-5.4." — Michael Truell, Cursor

What Your Agent Delivers

• Best agentic coding: 82.7% Terminal-Bench 2.0 means fewer broken actions and fewer wasted iterations through file, terminal, and database tools on Softgen
• Better cross-file project handling: the 1M-token window keeps your entire codebase in scope for large refactors and complex multi-service architectures
• Stronger reasoning on hard problems: 35.4% FrontierMath Tier 4 (up from 27.1%) — tackles tricky architecture decisions and debugging more reliably
• Top computer use: 78.7% OSWorld means the agent navigates multi-step UI and tool workflows with fewer dead ends
• Persistent execution: understands user intent faster and manages multi-step tasks independently — planning, tool use, error checking, and recovery

Cost

Official Rates:

• Input: $5 per 1M tokens
• Cached input: $0.50 per 1M tokens
• Output: $30 per 1M tokens

GPT-5.5 costs roughly 2× more than GPT-5.4 on a per-token basis. In practice, sessions often stay competitive because the model needs fewer correction loops — it gets things right the first time more often.

Typical costs: ~$0.60 for a landing page, ~$2.00 for a small app, ~$5.00 for a complex build.

Building Web Apps with GPT-5.5 on Softgen

GPT-5.5 is the right choice when your project is complex, the codebase is large, or you've been hitting repeated correction loops with other models. The 82.7% Terminal-Bench score means agentic tool execution on Softgen — file operations, terminal commands, database queries — runs more reliably and with fewer retries.

The 1M-token context keeps multi-file projects coherent across long sessions. When fewer mistakes and fewer retries matter more than token cost, GPT-5.5 is the model to reach for.

When to Use a Different Model

• Complex UI design work (try Claude 4.5)
• Budget-conscious builds (try GPT-5.4 or GPT-5.2)
• Fast prototypes and MVPs (try Claude Haiku 4.5 or Gemini 3 Flash)
• Best overall design + reasoning combo (try Claude Opus 4.7)

The Bottom Line

GPT-5.5 is OpenAI's strongest model for agentic coding and complex web app development. It leads every relevant benchmark and brings noticeably better judgment and persistence to multi-step Softgen sessions.

Best for: Large, complex web apps; multi-step agentic workflows; long-context refactors; and projects where code quality and fewer retries justify premium pricing.

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Want to learn more? Read the official GPT-5.5 announcement from OpenAI for comprehensive benchmarks and technical details.