The short answer
For a new production API integration, this is no longer a live, like-for-like choice if Gemini 3 Pro means Google’s gemini-3-pro-preview endpoint. Google says that Gemini API model was shut down on March 9, 2026. OpenAI’s API documentation lists gpt-5.2, but calls it a previous flagship and recommends its newer flagship for new use. Consider GPT-5.2 if you specifically need that version; for a new build, shortlist currently supported models instead. (ai.google.dev)
Historically, the specifications suggest different trade-offs, but they do not establish a universal performance winner. Gemini 3 Pro Preview had a larger documented input limit and more listed input modalities. OpenAI lists GPT-5.2’s text and image inputs, text output, and per-token prices. Neither a spec sheet nor early editorial testing establishes which model would do better on your production workload. (ai.google.dev)
Scope: GPT-5.2 is an API model; ChatGPT can also mean OpenAI’s consumer app, which is a different comparison. This article compares the GPT-5.2 API model with Google’s Gemini Developer API model
gemini-3-pro-preview. The shutdown statement applies to that named Gemini API endpoint; confirm the provider, endpoint, and model ID for any other offering before deciding.
At a glance
| Production question | GPT-5.2 API | Gemini 3 Pro API (gemini-3-pro-preview) |
|---|---|---|
| Can you call it through the named API now? | OpenAI lists gpt-5.2 and snapshot gpt-5.2-2025-12-11, and labels the model a previous flagship. |
No, not through the Gemini API: Google lists the preview as shut down March 9, 2026. |
| Documented input and context | Text and image input; 400,000-token context window. | Text, image, video, audio, and PDF input; 1,048,576-token input limit. These are historical specifications for the retired endpoint. |
| Documented output | Text. | Text; documented output-token limit is 65,536. This is a historical specification for the retired endpoint. |
| API price information | OpenAI lists $1.75 per 1 million input tokens and $14 per 1 million output tokens. | Google’s November 2025 launch announcement listed preview prices of $2 per 1 million input tokens and $12 per 1 million output tokens for prompts up to 200,000 tokens. Historical price only—not a current quote for a callable Gemini 3 Pro endpoint. |
OpenAI’s model page identifies the GPT-5.2 model and snapshot, its listed input/output modalities, and standard input/output prices. The 400,000-token context figure is documented for GPT-5.2. Google’s model page gives Gemini 3 Pro Preview’s historical limits and modalities, and marks the endpoint shut down. (developers.openai.com)
What the capability evidence does—and doesn’t—say
The historical specifications may help explain why teams considered these models, but they are not a current deployment recommendation. Gemini 3 Pro Preview’s documented 1,048,576-token input limit was larger than GPT-5.2’s 400,000-token context window. Google’s page lists text, image, video, audio, and PDF inputs for Gemini 3 Pro Preview; OpenAI’s GPT-5.2 page lists text and image input, with text output. These describe documented interfaces and limits—not accuracy, speed, or quality on your application. (ai.google.dev)
Google’s retired Gemini model page lists capabilities including function calling, structured outputs, code execution, file search, search grounding, thinking, and URL context. Those listings do not change the shutdown status. If your integration depends on any particular feature, check its availability and constraints on the currently supported endpoint you intend to use; don’t assume a replacement behaves identically. (ai.google.dev)
Historical editorial results are only tentative clues. PCMag’s late-2025 hands-on comparison reported that Gemini 3 Pro performed as well as or better than GPT-5.2 on some computer-science, math, and physics questions, and described improved deep research. The author characterized the work as initial testing, not a controlled or comprehensive API evaluation. PCMag’s image-recognition and creative-writing examples concerned Gemini 3 Flash, not Gemini 3 Pro, so they are not Pro-versus-GPT-5.2 results. (me.pcmag.com)
API availability and cost: the practical difference
For the Gemini Developer API, the exact model name matters: Google documents gemini-3-pro-preview as shut down on March 9, 2026. Don’t build against that endpoint. If you are considering another Google model or a different provider’s offering, verify its exact model ID and availability in that provider’s own documentation. (ai.google.dev)
OpenAI lists GPT-5.2 as a previous flagship and recommends a newer model for new use. Its documented standard rates are in USD per 1 million tokens: $1.75 for input and $14 for output. A real estimate depends on your input and output token volumes and the applicable current pricing terms. (developers.openai.com)
Google announced Gemini 3 Pro Preview at $2 per million input tokens and $12 per million output tokens for prompts up to 200,000 tokens in November 2025. That was a preview price, not a valid current budget estimate for the shut-down Gemini API model. Don’t use historical price comparisons to choose a present-day production endpoint.
How to make a production decision
- Pin the exact endpoint and version. OpenAI lists
gpt-5.2andgpt-5.2-2025-12-11. Do not build against the shut-down Gemini Developer API modelgemini-3-pro-preview; identify a currently available alternative and verify it in the provider’s catalog. (developers.openai.com) - Use representative tasks and a shared scorecard. Prepare examples from your application—such as extraction, code changes, document analysis, or multimodal interpretation—and define correctness before comparing outputs. Treat general benchmark claims and single anecdotes as clues, not production results.
- Repeat variable tasks. When output variation matters, run identical cases more than once. Record task success, invalid or incomplete outputs, tool-call correctness, and latency under comparable conditions. These are suggested evaluation measures, not published results for either model.
- Estimate cost from your traffic shape. For each candidate that is actually available, measure typical input and output tokens per request, then apply that provider’s current rates and relevant service terms. Keep consumer-app subscriptions separate from API usage charges.
- Choose against deployment requirements. If GPT-5.2 meets your quality and operational thresholds and you specifically need that version, it is listed in OpenAI’s API documentation. If you need a live Google API, shortlist a supported Google model and evaluate it afresh; Gemini 3 Pro’s historical context limit, features, and preview price do not guarantee a replacement’s behavior.
Bottom line
As of November 9, 2026, GPT-5.2 versus Gemini 3 Pro is not a straightforward production API bake-off on the Gemini Developer API: gemini-3-pro-preview has been shut down, while OpenAI lists GPT-5.2 as a previous flagship. For an existing GPT-5.2 integration, test whether that pinned version still meets your quality and cost requirements. For a new system, compare currently available models on your own workload rather than choosing from this retired pairing’s historical impressions or preview prices. (ai.google.dev)
Sources
Gemini 3 Pro preview | Gemini API
Gemini 3 for developers: New reasoning, agentic capabilities
I Tested the New GPT-5.2—It Just Can't Compete With Google Gemini 3