OpenAI

GPT-5.3 Codex

CTX400K

93Quality

Reasoning · Vision · Tools

Input$1.75/M

Output$14/M

Coding-optimized GPT model for repository edits, reviews, and agentic software work

PaidProprietary773/1044

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OpenAITextRare

GPT-5.3 Codex

Coding-optimized GPT model for repository edits, reviews, and agentic software work

gpt-5.3-codex

Type: Text
Quality: 93 · Top 7% on the Epoch Capabilities Index
Context window: 400,000 tokens
Max output: 128,000 tokens
Input price: $1.75 / 1M tokens
Output price: $14.00 / 1M tokens
Cache read: $0.17 / 1M tokens
Cache write: —
Released: Feb 5, 2026
Knowledge cutoff: Aug 2025
Takes in: Text, Image, PDF
Puts out: Text
Reasoning: Yes
Tool calling: Yes
Structured output: Yes
File attachments: Yes
Access: Paid
License: Proprietary
Rarity: Rare
Set number: 773/1044

Open OpenAI docs Quality 93 Where to run it 31 Meet its creature Battle Kimi K3

Weights aren’t public. Use is governed by OpenAI’s terms. Specs from models.dev, last changed Oct 19, 2026. Official source: platform.openai.com.

How good is it?

Public leaderboard scores for GPT-5.3 Codex, refreshed daily from Epoch AI and LMArena.

Top 7% of the 277 models on the Epoch Capabilities Index: #21.

Quality is the share of a leaderboard’s models this one beats, from 0 to 100. Chat models are rated on Epoch AI’s Capabilities Index when it lists them, otherwise on LMArena; image and video models on LMArena’s image and video arenas.

Leaderboards

Epoch Capabilities Index#21 of 277
One number fitted from dozens of hard benchmarks, from science questions to agentic coding.156.8 index
LMArena WebDev#105 of 145
Each model builds a web app from the same prompt; people pick the better one.1,407 rating
Listed as GPT-5.3-Codex (Codex Harness)

Benchmarks Epoch AI runs

75%SWE-bench VerifiedFixing real issues in open-source Python projects

Scores from Epoch AI and LMArena, licensed CC BY 4.0. Boards list models under their own names, so a close match is shown with the name it was scored under. Credits

Where to run it

31 providers sell GPT-5.3 Codex through an API. Prices are per million tokens, cheapest first.

CheapestCommandCode$2.00 in · $8.00 out
From the labOpenAI$1.75 in · $14.00 out

API providers

Provider	Input	Output	Context
CommandCodeCheapest paid`gpt-5.3-codex`	$2.00	$8.00	400K
Poe`openai/gpt-5.3-codex`	$1.60	$13.00	400K
Abacus`gpt-5.3-codex`	$1.75	$14.00	400K
AIHubMix`gpt-5.3-codex`	$1.75	$14.00	400K
Azure`gpt-5.3-codex`	$1.75	$14.00	400K
Azure Cognitive Services`gpt-5.3-codex`	$1.75	$14.00	400K
DevPass (LLM Gateway)`gpt-5.3-codex`	$1.75	$14.00	400K
Eden AI`openai/gpt-5.3-codex`	$1.75	$14.00	400K
FastRouter`openai/gpt-5.3-codex`	$1.75	$14.00	400K
FreeModel`gpt-5.3-codex`	$1.75	$14.00	400K

Show 21 more providers

Provider	Input	Output	Context
FrogBot`gpt-5-3-codex`	$1.75	$14.00	400K
GitHub Copilot`gpt-5.3-codex`	$1.75	$14.00	400K
Impossibl`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Kilo Gateway`openai/gpt-5.3-codex`	$1.75	$14.00	400K
LLM Gateway`azure/gpt-5.3-codex`	$1.75	$14.00	400K
NanoGPT`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Neon`gpt-5-3-codex`	$1.75	$14.00	400K
Ofox`openai/gpt-5.3-codex`	$1.75	$14.00	400K
OpenAIOfficial`gpt-5.3-codex`	$1.75	$14.00	400K
OpenCode`gpt-5.3-codex`	$1.75	$14.00	400K
OpenRouter`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Opper`gpt-5.3-codex`	$1.75	$14.00	400K
OrcaRouter`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Pioneer`gpt-5.3-codex`	$1.75	$14.00	400K
Prime Inference`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Requesty`gpt-5.3-codex`	$1.75	$14.00	400K
Venice AI`openai-gpt-53-codex`	$1.75	$14.00	400K
Vercel AI Gateway`openai/gpt-5.3-codex`	$1.75	$14.00	400K
Vivgrid`gpt-5.3-codex`	$1.75	$14.00	400K
ZenMux`openai/gpt-5.3-codex`	$1.75	$14.00	400K
AI/ML API`openai/gpt-5.3-codex`	$4.81	$38.51	400K

From models.dev and Hugging Face, checked daily. Resellers’ listings can lag behind their price pages, so confirm with the provider before you commit.

Face off

Current text models from other labs at a similar output price.

GPT-5.3 Codex

GPT-5.3 Codex

How good is it?

Leaderboards

Benchmarks Epoch AI runs

Where to run it

API providers

Face off

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