3 models
Ranked by SWE-Atlas Codebase QnA
Reasoning Tools JSON 79.1

GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...

openai/gpt-5.5 2026-04-23 1.05M context $5/M input $30/M output
46 providers
Reasoning Tools JSON 72.9

GPT-5.4 is OpenAI’s latest frontier model, unifying the Codex and GPT lines into a single system. It features a 1M+ token context window (922K input, 128K output) with support for...

openai/gpt-5.4 2026-03-05 1.05M context $2.5/M input $15/M output
42 providers
Reasoning Tools JSON 32.6

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

openai/gpt-5.3-codex 2026-02-05 400K context $1.75/M input $14/M output
28 providers