--- title: "GPT-5.3-Codex AI model: facts and benchmarks | Kendr" canonical: "https://kendr.org/models/openai-gpt-5-3-codex" date_modified: "2026-08-12" profile_kind: "reference" --- # GPT-5.3-Codex model profile GPT-5.3-Codex is a OpenAI model profile with a 400,000-token context window. The dated catalog snapshot records text, image, file modalities and interfaces for file input, prompt caching, reasoning controls, structured output, text generation. GPT-5.3-Codex is an independent knowledge profile. It does not claim that Kendr hosts the model, quote a Kendr customer price, promise API availability, or advertise a Kendr routing receipt. GPT-5.3-Codex accepts text, image, and file and returns text. The snapshot records file input, prompt caching, reasoning controls, structured output, text generation, tool calling, vision, and web search pricing as capabilities or interfaces. The dated reference snapshot lists $1.75 input and $14 output per million tokens. Cached input is $0.175 per million tokens. The 2026-08-12 snapshot includes 13 Design Arena categories. Publisher-reported launch results are labeled and are not presented as Kendr measurements; scores from different suites are not treated as interchangeable. GPT-5.3-Codex ranked #89 in the cited trailing-7-day third-party catalog usage dataset as of 2026-08-12. Observed within the cited trailing-7-day third-party catalog usage dataset; this is not global AI market share. Profile data was reviewed for the 2026-08-12 snapshot. Claims retain their source dates, and unavailable fields are shown as unavailable instead of estimated. ## Profile facts - **Profile type:** Model research profile - **Provider or publisher:** OpenAI - **Context window:** 400,000 tokens - **Snapshot date:** 2026-08-12 - **Reference catalog ID:** openai/gpt-5.3-codex ## Context, modalities, and identity GPT-5.3-Codex accepts text, image, and file and returns text. The snapshot records file input, prompt caching, reasoning controls, structured output, text generation, tool calling, vision, and web search pricing as capabilities or interfaces. - **Provider or publisher:** OpenAI - **Context window:** 400,000 tokens - **Maximum output:** 128,000 tokens - **Input modalities:** text, image, and file - **Output modalities:** text - **Knowledge cutoff:** Not disclosed ## Capabilities and supported controls Capabilities and parameters are reported from the dated catalog and source records; their presence does not guarantee identical behavior across every provider route. - **Supported parameters:** include_reasoning, max_completion_tokens, max_tokens, reasoning, reasoning_effort, response_format, seed, structured_outputs, tool_choice, tools - file input - prompt caching - reasoning controls - structured output - text generation - tool calling - vision - web search pricing ## Dated pricing snapshot The dated reference snapshot lists $1.75 input and $14 output per million tokens. Cached input is $0.175 per million tokens. These are dated third-party reference prices, not Kendr prices or an availability offer. Routes, tiers, caching, region, and provider policy can change the landed price. - **Price date:** 2026-08-12 - **Input:** $1.75 per 1M tokens - **Cached input:** $0.175 per 1M tokens - **Output:** $14 per 1M tokens ## Benchmark evidence and limitations The 2026-08-12 snapshot includes 13 Design Arena categories. Publisher-reported launch results are labeled and are not presented as Kendr measurements; scores from different suites are not treated as interchangeable. Third-party catalog fields normalized from the cited model dataset; benchmark methodology and coverage differ by source. | Design Arena category | Elo | Win rate | Rank | | --- | --- | --- | --- | | androidnative | 1084 | 35.2% | #29 | | fullstack | 1018 | 36.4% | #34 | | godotgamedev | 1124 | 45.1% | #24 | | mobileapps | 1109 | 41.4% | #35 | | webapps | 1075 | 36.9% | #32 | | 3d | 1062 | 35.3% | #89 | | asciiart | 1189 | 51.2% | #29 | | codecategories | 1170 | 47.2% | #64 | | dataviz | 1190 | 50.5% | #54 | | gamedev | 1202 | 51.3% | #48 | | svg | 1175 | 54% | #40 | | uicomponent | 1171 | 47.3% | #63 | | website | 1183 | 48.6% | #63 | ## Popularity and market context GPT-5.3-Codex ranked #89 in the cited trailing-7-day third-party catalog usage dataset as of 2026-08-12. Observed within the cited trailing-7-day third-party catalog usage dataset; this is not global AI market share. - **Third-party catalog rank:** #89 - **Global market share:** Not inferred - **Observation date:** 2026-08-12 ## Frequently asked questions ### What is GPT-5.3-Codex? GPT-5.3-Codex is a OpenAI model profile with a 400,000-token context window. The dated catalog snapshot records text, image, file modalities and interfaces for file input, prompt caching, reasoning controls, structured output, text generation. ### What context window does GPT-5.3-Codex have? The dated profile lists 400,000 tokens of context and up to 128,000 output tokens. Provider routes, variants, and runtime configuration can impose lower effective limits. ### What benchmark evidence is available for GPT-5.3-Codex? The 2026-08-12 snapshot includes 13 Design Arena categories. Publisher-reported launch results are labeled and are not presented as Kendr measurements; scores from different suites are not treated as interchangeable. Third-party catalog fields normalized from the cited model dataset; benchmark methodology and coverage differ by source. ### Is GPT-5.3-Codex available through Kendr? This is an independent knowledge profile, not a Kendr-hosted availability claim. Check Kendr's live public model API for currently enabled Kendr aliases. ### Does the popularity rank represent GPT-5.3-Codex's global market share? GPT-5.3-Codex ranked #89 in the cited trailing-7-day third-party catalog usage dataset as of 2026-08-12. Observed within the cited trailing-7-day third-party catalog usage dataset; this is not global AI market share. No global market-share percentage is inferred when the source does not publish one. ## Sources and evidence dates - [GPT-5.3-Codex third-party catalog record](https://openrouter.ai/openai/gpt-5.3-codex) — catalog, checked 2026-08-12 - [Third-party model catalog methodology](https://openrouter.ai/docs/guides/overview/models) — methodology, checked 2026-08-12 - [OpenAI official model documentation](https://developers.openai.com/api/docs/models) — primary, checked 2026-08-12 - [Design Arena leaderboard and methodology](https://www.designarena.ai/leaderboard) — benchmark, checked 2026-08-12 Live Kendr operational availability is published separately at https://api.kendr.org/api/public/models.