Model comparison
Compare Gemini 3.8 Live Extended Thinking and GPT-Realtime-2.1 using the same provider-sourced voice & realtime rubric. No mystery score and no invented benchmark ranking.
Quick take
A separate Gemini voice model that works through complex requests in the background while keeping the conversation going.
Integration differs from standard Live: tools must be asynchronous, and the app must track interaction_status. A finished utterance does not mean the background task has finished.
OpenAI's realtime speech-to-speech reasoning model for tool-using voice agents that also need text and image context.
There is no published universal latency number, and audio-token costs are hard to compare directly with minute- or character-priced competitors.
Compare the published facts
Values use each provider's own published units and limits. A blank means the provider did not publish a directly comparable value in the sources reviewed.
| Voice & realtime | Gemini 3.8 Live Extended Thinking | GPT-Realtime-2.1 |
|---|---|---|
| Price basisToken-, character-, or minute-based price for the listed access route. | Audio $0.005/min in · $0.018/min out | Audio $32 in · $64 out / 1M tokens |
| Interaction modeSpeech-to-speech, audio-to-audio, or streamed text-to-speech behavior. | Speech-to-speech with visual input and background reasoning | Speech-to-speech with text/image context |
| Published latencyProvider-published measurement with its stated exclusions; not a Cody test. | Not published | Not published |
| LanguagesProvider-documented language coverage or a clear unpublished marker. | Multilingual; verify current Live API support | Multilingual; exact list not published here |
| Tools & controlNative function calling, reasoning, or speech-control features. | Async functions only, search grounding | Function calling and configurable reasoning |
| Context or input limitDocumented token or character limit where it is meaningful. | 131,072 input · 65,536 output | 128K input · 32K max output |
How to choose
Start with the job you need to complete, then validate cost, access, and policy details on your exact provider route.
Google says paid Gemini API prompts and responses are not used to improve its products. Unpaid-service content generally may be used, with different treatment for EEA, UK, and Swiss users; check the current terms for your account and region.
Provider and API links
OpenAI says API content is not used for training by default. Default abuse-monitoring logs may be retained up to 30 days, with additional controls available to qualifying organizations.
Provider and API links
Frequently asked questions
Gemini 3.8 Live Extended Thinking: A separate Gemini voice model that works through complex requests in the background while keeping the conversation going. GPT-Realtime-2.1: OpenAI's realtime speech-to-speech reasoning model for tool-using voice agents that also need text and image context.
Consider Gemini 3.8 Live Extended Thinking when your priority is Multi-step voice support workflows. Consider GPT-Realtime-2.1 when your priority is Tool-using customer or employee voice agents. Test both with your own data and provider route before committing.
No. This comparison aligns provider-published facts for the Voice & realtime category. It does not claim a universal winner or combine incompatible third-party benchmark scores.
