GPT 5.3 Codex
PremiumOpenAI's most advanced agentic coding model with 400K context.
Combines frontier software engineering with broader reasoning and professional knowledge. Excels at extended tool-using workflows — development, debugging, deployment, and product iteration. ~25% faster and more token-efficient than GPT 5.2 Codex.
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GPT 5.3 Codex by OpenAI has a Capability Index of 87.0, making it notably capable. It ranks #8 out of 92 models on the idapt capability leaderboard. It resolves 75% of SWE-bench Verified coding tasks. GPT 5.3 Codex is somewhat expensive at $1.75/M tokens input and $14.00/M tokens output. Cached input reads are priced at $0.17/M tokens, making repeated context cheaper. The model supports vision/image input, extended reasoning, a 400K context window.
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Mistral Small 4vs GPT 5.3 CodexFrequently Asked Questions about GPT 5.3 Codex▼
When was GPT 5.3 Codex released?
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GPT 5.3 Codex was released on February 24, 2026.
Who created GPT 5.3 Codex?
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GPT 5.3 Codex was created by OpenAI.
How capable is GPT 5.3 Codex?
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GPT 5.3 Codex has a Capability Index of 87.0/100, making it notably capable. It ranks #8 out of 92 models.
How much does GPT 5.3 Codex cost?
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GPT 5.3 Codex costs $1.75/M input tokens and $14.00/M output tokens.
What is GPT 5.3 Codex API pricing?
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The GPT 5.3 Codex API is priced at $1.75 per million input tokens and $14.00 per million output tokens. You can access GPT 5.3 Codex through idapt.app alongside 200+ other AI models in one workspace.
Is GPT 5.3 Codex a reasoning model?
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Yes, GPT 5.3 Codex is a reasoning model. It can think step-by-step through complex problems before providing an answer, often yielding better results on difficult tasks like math, coding, and multi-step logic.
Does GPT 5.3 Codex support image or vision input?
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Yes, GPT 5.3 Codex supports vision/image input. You can share images in your conversation and the model will analyze and respond based on their content.
Does GPT 5.3 Codex support audio?
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No, GPT 5.3 Codex does not support audio input.
What is the context window of GPT 5.3 Codex?
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GPT 5.3 Codex has a context window of 400K tokens, meaning it can process approximately 300,000 words of context at once.
Is GPT 5.3 Codex open source?
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GPT 5.3 Codex is a proprietary model developed by OpenAI. The model weights and training data are not publicly available.
How does GPT 5.3 Codex perform on coding?
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GPT 5.3 Codex resolves 75% of SWE-bench Verified tasks — real GitHub issues fixed end-to-end, the strongest single signal for agentic software engineering.
What is GPT 5.3 Codex good at?
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Based on benchmark data, GPT 5.3 Codex excels at: complex reasoning and analysis, software development and coding tasks, visual analysis and image understanding. It is OpenAI's capable model suitable for a wide range of tasks.
Where can I use GPT 5.3 Codex?
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You can chat with GPT 5.3 Codex on idapt.app — no separate API key required. idapt is an AI workspace with 200+ models, agents, computers, and tasks. You can also access GPT 5.3 Codex through OpenAI's own API or platform.