Gemini 3.1 Flash TTS Preview vs GPT-5.2 Codex
Gemini 3.1 Flash TTS Preview (2026) and GPT-5.2 Codex (2025) compare a standalone API model against a coding-specialized model. Gemini 3.1 Flash TTS Preview ships a 16K-token context window, while GPT-5.2 Codex ships a not-yet-sourced context window. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Gemini 3.1 Flash TTS Preview is standalone API model, while GPT-5.2 Codex is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Gemini 3.1 Flash TTS Preview | GPT-5.2 Codex |
|---|---|---|
| Product type | Standalone API model | Coding-specialized model |
| Best for | general production evaluation | custom coding agents, code generation, and tool loops |
| Decision fit | General | Coding, Agents, and Vision |
| Context window | 16K | — |
| Cheapest output | - | $14/1M tokens |
| Provider routes | 0 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Gemini 3.1 Flash TTS Preview has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.2 Codex has broader tracked provider coverage for fallback and procurement flexibility.
- GPT-5.2 Codex uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags GPT-5.2 Codex for Coding, Agents, and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Gemini 3.1 Flash TTS Preview
Unavailable
No complete token price in local provider data
GPT-5.2 Codex
$4,900
Cheapest tracked route/tier: Vercel AI Gateway
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Gemini 3.1 Flash TTS Preview and GPT-5.2 Codex; plan for SDK, billing, or endpoint changes.
- GPT-5.2 Codex adds Vision, Multimodal, and Reasoning in local capability data.
- No overlapping tracked provider route is sourced for GPT-5.2 Codex and Gemini 3.1 Flash TTS Preview; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-15 | 2025-12-18 |
| Context window | 16K | — |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | 2025-08 |
Pricing and availability
| Pricing attribute | Gemini 3.1 Flash TTS Preview | GPT-5.2 Codex |
|---|---|---|
| Input price | - | $1.75/1M tokens |
| Output price | - | $14/1M tokens |
| Providers | - |
Capabilities
| Capability | Gemini 3.1 Flash TTS Preview | GPT-5.2 Codex |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | No | Yes |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | No | No |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: GPT-5.2 Codex, multimodal input: GPT-5.2 Codex, reasoning mode: GPT-5.2 Codex, function calling: GPT-5.2 Codex, tool use: GPT-5.2 Codex, and code execution: GPT-5.2 Codex. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Gemini 3.1 Flash TTS Preview has no token price sourced yet and GPT-5.2 Codex has $1.75/1M input tokens. Provider availability is 0 tracked routes versus 1. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Gemini 3.1 Flash TTS Preview when provider fit are central to the workload. Choose GPT-5.2 Codex when coding workflow support and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Is Gemini 3.1 Flash TTS Preview or GPT-5.2 Codex open source?
Gemini 3.1 Flash TTS Preview is listed under Proprietary. GPT-5.2 Codex is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Gemini 3.1 Flash TTS Preview or GPT-5.2 Codex?
GPT-5.2 Codex has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Gemini 3.1 Flash TTS Preview or GPT-5.2 Codex?
GPT-5.2 Codex has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Gemini 3.1 Flash TTS Preview or GPT-5.2 Codex?
GPT-5.2 Codex has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for function calling, Gemini 3.1 Flash TTS Preview or GPT-5.2 Codex?
GPT-5.2 Codex has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Gemini 3.1 Flash TTS Preview and GPT-5.2 Codex?
Gemini 3.1 Flash TTS Preview is available on the tracked providers still being sourced. GPT-5.2 Codex is available on Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.