Skip to content
AI Atlas
ModelActiveProprietary

gpt-5.3-codex

OpenAIdevelopers.openai.com/api/docs/models/gpt-5.3-co

The most capable agentic coding model to date.

quality72

Updated 16 min ago · first seen 11 Sept 2026

model_01M293V7A5QHQMWWCQSF812S6G

Context
400K tokens
T2 · 16 min ago
Released
24 Feb 2026
T2 · 16 min ago

Specification

Release date
24 Feb 2026

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Openness
proprietary

Source:OpenAI Platform docsT1observed 34 min agohigh

Context window
400K tokens

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Max output
128K tokens

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Modalities
image, text

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Input modalities
image, text

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Output modalities
text

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Tokenizer
GPT

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

API model id
gpt-5.3-codex

Source:OpenAI Platform docsT1observed 35 min agohigh

Official page

Source:OpenAI Platform docsT1observed 34 min agohigh

File input
Yes

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Openrouter id
openai/gpt-5.3-codex

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Supported parameters
include_reasoning, max_completion_tokens, max_tokens, reasoning, reasoning_effort, response_format, seed, structured_outputs, tool_choice, tools

Source:OpenRouter public model & pricing listingT2observed 16 min agomedium

Each value shows its source, tier and observation time. Conflicting claims are kept side by side and flagged — never averaged. How AI Atlas records facts →

Provenance

Attributed facts

18

Source tiers

T1T24 / 14

Freshest observation

16 min ago

Conflicts

None