Best AI Agents for Full-Stack Apps — OpenAI
The best OpenAI model for building full-stack apps is GPT-5.5, rated 1128 in Design Arena's full-stack agent arena — given a brief and a tool loop, and judged on what it actually shipped. GPT-5.6 Terra (1096) and GPT-5.2 (1084) round out the top three.
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gpt-5.5ReasoningToolsJSON+154.8 intel · $5.00/M · 1.1M ctx1128Agent Elo - 2gpt-5.6-terraReasoningToolsJSON+155.0 intel · $1.00/M · 83 t/s1096Agent Elo
- 3gpt-5.2ReasoningToolsJSON+142.2 intel · $1.75/M · 81 t/s1084Agent Elo
- 4gpt-5.4ReasoningToolsJSON+151.4 intel · $2.50/M · 1.1M ctx1060Agent Elo
- 5gpt-5.2-codexReasoningToolsJSON+140.1 intel · $1.75/M · 400K ctx1034Agent Elo
- 6gpt-5.3-codexReasoningToolsJSON+144.3 intel · $1.75/M · 122 t/s1025Agent Elo
How this is ranked
Models ranked by Design Arena Elo in the full-stack agent arena — each one is given a brief and a tool loop and has to build a working application, with humans judging the results head to head. This measures something a static coding benchmark cannot: whether a model can hold a multi-file project together, recover from its own mistakes, and finish.
Frequently asked
Which OpenAI model builds the best full-stack app?
The best OpenAI model for building full-stack apps is GPT-5.5, rated 1128 in Design Arena's full-stack agent arena — given a brief and a tool loop, and judged on what it actually shipped. GPT-5.6 Terra (1096) and GPT-5.2 (1084) round out the top three.
What's a good alternative to GPT-5.5?
GPT-5.6 Terra (1096) is the closest alternative on this metric, followed by GPT-5.2 (1084). See the full ranking above for the tradeoffs.
How many OpenAI models are there?
modelgrep tracks 60 OpenAI models with live benchmarks, speed, latency and per-provider pricing, led on intelligence by GPT-5.6 Sol. 6 of them qualify for this ranking.