Gemini 3.1 Pro vs GPT-5.3 Codex
Model Markets Rankings
Intelligence, Cost, and Efficiency
| Ranking | Gemini 3.1 Pro | GPT-5.3-Codex |
|---|---|---|
| CostLower is better · Published-token output estimate | #22 of 36$0.161 per LiveBench case | UnrankedNot in the 36-model eligible cohort |
Ranks come from the current complete eligible cohorts. Green highlights appear only when both models are ranked in the same metric. Missing required inputs remain unranked, and the three dimensions are not collapsed into an overall winner.
Benchmark Performance
Available Benchmarks
Technical Differences
Side-by-Side Facts
| Field | Gemini 3.1 Pro | GPT-5.3-Codex |
|---|---|---|
| Developer | Google DeepMind | OpenAI |
| Family | Gemini 3 | Gpt 5 3 |
| Model | Gemini 3.1 Pro | GPT-5.3-Codex |
| Version | Gemini 3.1 Pro | GPT-5.3-Codex |
| Lifecycle | preview | active |
| Released | Unknown | Unknown |
| Knowledge cutoff | Unknown | 2025-08-31 |
| Input modalities | Text, Image, Video, Audio, Document | Text, Image |
| Output modalities | Text | Text |
| Context window | 1,049K | 400K |
| Total parameters | Unknown | Unknown |
| Active parameters | Unknown | Unknown |
| License | Unknown | Unknown |
| Open weights | No | No |
| API available | Yes | Yes |
| Self-hostable | No | No |
| Provider access | Google AI (Standard), Google Gemini (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | chat, generation, reasoning, tools | chat, generation, reasoning, structured_outputs, tools |
13 comparable fields · 9 material differences · Pair passes the primary-source comparison gate
Gemini 3.1 Pro Capabilities
GPT-5.3 Codex Capabilities
Internal Comparison Graph
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Primary Evidence
Sources and Freshness
Questions
Gemini 3.1 Pro vs GPT-5.3 Codex FAQs
Is Gemini 3.1 Pro or GPT-5.3 Codex better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Gemini 3.1 Pro and GPT-5.3 Codex, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Gemini 3.1 Pro or GPT-5.3 Codex?+
Gemini 3.1 Pro is $2.00 and GPT-5.3 Codex is $1.75 per million tokens, so GPT-5.3 Codex is cheaper on this metric. Gemini 3.1 Pro is $12.00 and GPT-5.3 Codex is $14.00 per million tokens, so Gemini 3.1 Pro is cheaper on this metric.
Which has a larger context window, Gemini 3.1 Pro or GPT-5.3 Codex?+
Gemini 3.1 Pro has the larger sourced context window. Gemini 3.1 Pro supports 1,049K and GPT-5.3 Codex supports 400K.
Which performs better in benchmarks, Gemini 3.1 Pro or GPT-5.3 Codex?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Gemini 3.1 Pro or GPT-5.3 Codex be self-hosted?+
Both models have the same recorded self-hosting status: unsupported. Gemini 3.1 Pro is not marked open weight; GPT-5.3 Codex is not marked open weight.
Can Gemini 3.1 Pro and GPT-5.3 Codex understand images?+
Gemini 3.1 Pro is documented with image input; GPT-5.3 Codex is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Gemini 3.1 Pro or GPT-5.3 Codex?+
GPT-5.3 Codex has the larger sourced maximum output: Gemini 3.1 Pro supports 66K and GPT-5.3 Codex supports 128K output tokens.
Do Gemini 3.1 Pro and GPT-5.3 Codex support reasoning and tool use?+
Gemini 3.1 Pro: reasoning, tool calling, and image input. GPT-5.3 Codex: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Gemini 3.1 Pro or GPT-5.3 Codex?+
Gemini 3.1 Pro has 2 sourced provider routes; GPT-5.3 Codex has 2, a tie.
Which offers better value, Gemini 3.1 Pro or GPT-5.3 Codex?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.