GPT-5.3-Codex by OpenAI — Pricing, Benchmarks & Real Outputs
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Alternatives to GPT-5.3-Codex
GPT-5.3-Codex is good. These would like a word anyway.
GPT-5.3-Codex is good. These would like a word anyway.
GPT-5.3-Codex is good. These would like a word anyway.
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 on SWE-Bench Pro and strong performance on Terminal-Bench 2.0 and OSWorld-Verified, reflecting improved multi-language coding, terminal proficiency, and real-world computer-use skills. The model is optimized for long-running, tool-using workflows and supports interactive steering during execution, making it suitable for complex development tasks, debugging, deployment, and iterative product work.
fromimport openai OpenAI
client = OpenAI(
"https://openrouter.ai/api/v1" base_url=,
"$OPENROUTER_API_KEY" api_key=,
)
response = client.chat.completions.create(
"openai/gpt-5.3-codex" model=,
"role""user""content""Hello!" messages=[{: , : }],
)
print(response.choices[0].message.content)Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.
A rigorous philosopher-engineer who explores moral problems with precision. Embraces nuance, refuses easy answers, and traces second-order effects others miss. Won't preach — will reason.
Structure-first, performance-second. Opens analytical responses with explicit assumptions, chains conclusions logically (So X → Therefore Y → Which means Z), and labels uncertainty honestly. Knows when NOT to overexplain. The model equivalent of a brilliant researcher at 2am — tired but precise, slightly wry, utterly unimpressed by superficial cleverness.
Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.
Unique words vs. total words. Higher = richer vocabulary.
Average words per sentence.
"Might", "perhaps", "arguably" per 100 words.
**Bold** markers per 1,000 characters.
Bullet and numbered list items per 1,000 characters.
Markdown headings per 1,000 characters.
Emoji per 1,000 characters.
"However", "moreover", "furthermore" per 100 words.
48 outputs from GPT-5.3-Codex
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 on SWE-Bench Pro and strong performance on Terminal-Bench 2.0 and OSWorld-Verified, reflecting improved multi-language coding, terminal proficiency, and real-world computer-use skills. The model is optimized for long-running, tool-using workflows and supports interactive steering during execution, making it suitable for complex development tasks, debugging, deployment, and iterative product work.
fromimport openai OpenAI
client = OpenAI(
"https://openrouter.ai/api/v1" base_url=,
"$OPENROUTER_API_KEY" api_key=,
)
response = client.chat.completions.create(
"openai/gpt-5.3-codex" model=,
"role""user""content""Hello!" messages=[{: , : }],
)
print(response.choices[0].message.content)Set OPENROUTER_API_KEY with your OpenRouter API key from openrouter.ai/keys.
A rigorous philosopher-engineer who explores moral problems with precision. Embraces nuance, refuses easy answers, and traces second-order effects others miss. Won't preach — will reason.
Structure-first, performance-second. Opens analytical responses with explicit assumptions, chains conclusions logically (So X → Therefore Y → Which means Z), and labels uncertainty honestly. Knows when NOT to overexplain. The model equivalent of a brilliant researcher at 2am — tired but precise, slightly wry, utterly unimpressed by superficial cleverness.
Taste is judged on an uncapped scale, originality first. The space past 100 is craft today's models rarely reach.
Unique words vs. total words. Higher = richer vocabulary.
Average words per sentence.
"Might", "perhaps", "arguably" per 100 words.
**Bold** markers per 1,000 characters.
Bullet and numbered list items per 1,000 characters.
Markdown headings per 1,000 characters.
Emoji per 1,000 characters.
"However", "moreover", "furthermore" per 100 words.
48 outputs from GPT-5.3-Codex