OpenAI
Chat with GPT-5.3 Codex online
OpenAI's coding agent — debugging, reviewing, deploying, not just writing the function.
400K tokens
컨텍스트
128,000 tokens
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이럴 때 활용하세요
Agentic development
Whole tasks across the lifecycle, not one snippet.
Debugging
Reads real failures and works towards the cause.
Code review
Reviews a change against the intent behind it.
Screenshot to fix
Takes images, so a broken UI can go in directly.
Prompts to steal
Tuned to this model — click any line to copy.
GPT-5.3 Codex 소개
GPT-5.3 Codex is OpenAI's coding specialist, announced on 5 February 2026. It combines the coding strength of the Codex line with the general reasoning and professional knowledge of the wider GPT-5 series, and OpenAI's framing of it is deliberately broad: Codex moves from an agent that writes and reviews code to an agent that can do most of what a developer does on a computer.
That shows up in what it is tuned for. Debugging, deploying, monitoring, writing specs, editing copy, tests and metrics are all in scope, not just producing a function on request. It sets high marks on the benchmarks that measure real repository work rather than puzzle-solving — SWE-Bench Pro and Terminal-Bench in particular — and OpenAI reports it runs roughly 25% faster than GPT-5.2 Codex, which matters more than it sounds when a model is doing dozens of steps in a row.
It exposes adjustable reasoning effort, so the same model can answer quickly or think hard depending on what the task deserves, and it takes images as input, so a screenshot of a broken build or an unreadable chart can go straight into the thread. The context window runs to about 400K tokens with up to 128K tokens of output, enough to hold a large slice of a repository plus a long agent transcript.
On NinjaChat it is included in every plan. Pick it from the model list when the work is software, and switch to a general model when it is not.
GPT-5.3 Codex 사용 방법
1분 안에 첫 결과물까지.
01
Create a NinjaChat account and choose a plan
02
Open chat and pick GPT-5.3 Codex from the model list
03
Give it the repository context, the failure and the goal
04
Ask for a plan first on anything that spans files
더 나은 결과를 위한 팁
- Paste the real error output rather than describing it
- Say explicitly which files are in scope
- Attach a screenshot when the bug is visual
- Switch to a general GPT-5 model for non-coding work
GPT-5.3 Codex vs 다른 대안들
{model}이 앞서는 부분과 그렇지 않은 부분, 솔직하게 비교합니다.
vs Kimi K2.7 Code
모델 보기OpenAI's reasoning-effort control and wider tooling
Kimi K2.7 Code is open-weights and cheaper per token
vs GPT-5.6 Terra
Tuned specifically for software and agent runs
Terra is the better all-round generalist
