GPT-4o vs Gemini 3.1 Pro
A side-by-side look at OpenAI's GPT-4o and Google's Gemini 3.1 Pro — covering API pricing, context window, latency, coding ability, and real-world fit, so you can pick the right model for what you're building.
Quick Verdict
Cost optimization across both models
Access either model through one API key. Pay only for what you use — save up to 70% vs official pricing.
Overview
GPT-4o and Gemini 3.1 Pro come from different camps — OpenAI versus Google — and they split most sharply on price and context. GPT-4o runs at $2.50/$10.00 per 1M tokens with a 128K window; Gemini 3.1 Pro sits at $2.00/$12.00 with 1M of context. Neither is objectively "better" — the right pick depends on what you're shipping.
In practice: Omni-modal flagship with native vision and audio. The most popular OpenAI model for general use. Google's current flagship. Best quality for complex reasoning and multimodal tasks. Both ship through AI API Hub on an OpenAI-compatible endpoint, so you can move between them by changing a single model name — and settle the bill with USDT or USDC, no credit card required.
On cost alone, Gemini 3.1 Pro is the cheaper of the two (Save $0.50 per 1M input), which adds up fast once real traffic hits. Use the calculator below to model your own volume.
Interactive Cost Calculator
Deep Specs Matchup
| Specification | GPT-4o | Gemini 3.1 Pro |
|---|---|---|
| Provider | OpenAI | |
| Release Date | 2024-05 | 2026-05 |
| Context Window | 128K | 1M |
| Max Output Tokens | 16,384 | 65,536 |
| Input Price | $2.50/1M | $2.00/1M |
| Output Price | $10.00/1M | $12.00/1M |
| Vision Support | Yes ✓ — image input | Yes ✓ — image input |
| Audio Support | No | Yes ✓ |
| Function Calling / Tool Use | Yes ✓ | No |
| JSON Mode Support | Yes ✓ | No |
| Streaming | Yes ✓ | No |
| Fine Tuning | Yes ✓ | No |
| Rate Limits (RPM/TPM) | 10K RPM | 1K RPM |
| Latency P95 | N/A | N/A |
| Latency P99 | N/A | N/A |
| Status | active | active |
Latency P95/P99: Not publicly disclosed by provider — marked N/A to avoid fabrication. Rate limits shown as published by the provider; plan-dependent where N/A. All data sourced from model-variants.ts.
Pros & Cons Analysis
GPT-4o
- ✓Tool use — function calling for AI agents
- ✓Multimodal — vision/image input supported
- ✓Advanced reasoning
- ✗Smaller context than 4.1
- ✗Superseded by GPT-5.4
Gemini 3.1 Pro
- ✓Coding ability — native code generation supported
- ✓Long-context reasoning — 1M window handles large documents
- ✓Multimodal — vision/image input supported
- ✗No function calling — limited for AI agents
- ✗Costly for high-volume
Benchmark Scores
| Benchmark | GPT-4o | Gemini 3.1 Pro |
|---|---|---|
| MMLU | N/A | N/A |
| HumanEval | N/A | N/A |
| SWE-bench | N/A | N/A |
| GSM8K | N/A | N/A |
| Arena Score | N/A | N/A |
E-E-A-T note: Benchmark data is sourced exclusively from official provider releases stored in our model registry. No estimated or inferred scores are shown.
🧠 Human Decision Summary
→If you are building a coding-heavy AI agent → Gemini 3.1 Pro is preferred.
→If your workload involves long document reasoning or multi-step instruction following → Gemini 3.1 Pro performs better with its 1M context.
→If cost is your primary constraint → Gemini 3.1 Pro provides ~20% lower cost per 1M tokens.
→If you need function-calling AI agents → GPT-4o is the only option with tool use support.
These recommendations are derived from each model's capabilities and pricing in our registry — not hand-written per page.
🏆 Winner per Dimension
| Category | Winner | Reason |
|---|---|---|
| Coding | Gemini 3.1 Pro | Native code generation + better price-performance |
| Long context | Gemini 3.1 Pro | Larger context window (1M) |
| Cost efficiency | Gemini 3.1 Pro | Lower input price — $2.00/1M vs $2.50/1M |
| Reasoning | Tie | Chain-of-thought / math specialization |
| Multimodal | Tie | Vision / image input support |
Real-world Use Cases
GPT-4o
- Code generation agentFunction calling enables autonomous code workflows
- RAG knowledge assistant128K context for document retrieval
- Document summarization systemVision + long context for image-heavy documents
Gemini 3.1 Pro
- RAG knowledge assistant1M context ingests large knowledge bases
- Document summarization systemVision + long context for image-heavy documents
- Customer support automationQuality responses for support workflows
Best For
| Use Case | GPT-4o | Gemini 3.1 Pro |
|---|---|---|
| Coding | ★★★ | ★★★ |
| AI Agents | ★★★ | ★ |
| Research | ★★★ | ★ |
| Writing | ★★★ | ★★ |
| Enterprise | ★★★ | ★★ |
Performance & Pricing Analysis
On performance, GPT-4o leans into advanced reasoning and pairs it with 128K of context — enough for advanced reasoning and multimodal. Gemini 3.1 Pro answers with flagship model across 1M, which makes it the stronger fit when you need flagship model and 1m context. The gap is real, but it's a question of fit rather than dominance.
Pricing is where they part ways. At $2.50/$10.00 versus $2.00/$12.00 per 1M tokens, Gemini 3.1 Pro is the clear budget pick. Run a typical workload of 1M requests/month at ~1K input / 500 output tokens and Gemini 3.1 Pro keeps roughly $500.00/month in your pocket.
Our take: if cost efficiency drives the decision, Gemini 3.1 Pro wins. Either way, both run through AI API Hub with USDT/USDC payments and instant activation — start with $5 and one API key covers every model.
How to Switch Between Models
Since both GPT-4o and Gemini 3.1 Pro are available through AI API Hub with OpenAI-compatible API format, switching between them requires only changing the model name parameter. Your existing SDK code works without modification.
from openai import OpenAI client = OpenAI(api_key="YOUR_KEY", base_url="https://api.apiyihe.org/v1") # Before: response = client.chat.completions.create(model="gpt-4o", messages=[...]) # After: response = client.chat.completions.create(model="gemini-3.1-pro", messages=[...])
import OpenAI from "openai";
const client = new OpenAI({apiKey: process.env.KEY, baseURL: "https://api.apiyihe.org/v1"});
// Before: model: "gpt-4o"
// After: model: "gemini-3.1-pro"curl https://api.apiyihe.org/v1/chat/completions \
-H "Authorization: Bearer YOUR_KEY" \
-d '{"model": "gemini-3.1-pro", "messages": [{"role":"user","content":"Hello"}]}'💡 AI API Hub supports both models through one API key. No separate accounts needed. Pay with USDT/USDC for all models.
Frequently Asked Questions
What is the difference between GPT-4o and Gemini 3.1 Pro?
They come from different providers and optimize for different things. GPT-4o is OpenAI's gpt4 model — 128K context, $2.50/1M input. Gemini 3.1 Pro is Google's gemini model — 1M context, $2.00/1M input. The short version: pick based on context size, price, and which capabilities your app actually needs.
Which model is cheaper?
Gemini 3.1 Pro is cheaper at $2.00/1M input. At typical volumes that difference compounds — run the cost calculator above with your real request count to see the monthly gap.
Which model is better for coding?
Gemini 3.1 Pro is the better coding pick — it has native code-generation support, while GPT-4o doesn't specialize there.
Which model has a larger context window?
Gemini 3.1 Pro wins on context — 1M versus 128K. That matters for long documents, large codebases, or multi-turn conversations that need to stay coherent.
Which model is faster?
Gemini 3.1 Pro generally responds faster — lighter models tend to have lower latency, though GPT-4o may pull ahead on complex reasoning where its larger capacity helps. For latency-critical apps, benchmark both at your real workload.
Which model should I choose?
It depends on your priority. If cost drives the decision, go with Gemini 3.1 Pro ($2.00/1M). If you need to process long documents or large contexts, Gemini 3.1 Pro and its 1M window is the safer bet. If you're building AI agents, GPT-4o is your only tool-calling option here. When in doubt, start with the cheaper model and upgrade only if quality demands it.
Can both models use function calling?
Not equally. GPT-4o supports function calling; Gemini 3.1 Pro does not. If agents are central to your app, that narrows the choice.
How much does GPT-4o cost?
GPT-4o runs $2.50/1M input and $10.00/1M output, with 128K of context. It's pay-as-you-go with no minimum — through AI API Hub you can start with $5 and scale up.
How much does Gemini 3.1 Pro cost?
Gemini 3.1 Pro runs $2.00/1M input and $12.00/1M output, with 1M of context. It's pay-as-you-go with no minimum — through AI API Hub you can start with $5 and scale up.
Which model is better for enterprise use?
Neither is exclusively enterprise-tier. For heavy enterprise use, look at the flagship options in each provider's lineup.
Which model is better for AI agents?
Agent support differs — see the function-calling answer above.
How do I access these APIs?
Both run through AI API Hub on one OpenAI-compatible endpoint. Register at api.apiyihe.org, deposit USDT or USDC (no credit card), grab your API key, and call https://api.apiyihe.org/v1 with model name "gpt-4o" or "gemini-3.1-pro". One key unlocks every model.
Can I switch between these models without changing my code?
Yes — because AI API Hub is OpenAI-compatible, moving from GPT-4o to Gemini 3.1 Pro (or back) is just a model-name change. Your SDK setup, message format, and streaming logic stay exactly the same.
Final Verdict: Which Should You Buy?
💰 Cheapest pricing · ⚡ Instant API key · 🚫 No credit card · 💎 Pay with USDT/USDC · 🔌 OpenAI-compatible
Conclusion: GPT-4o is the cheaper choice — save $500.00/month (6%) at your volume. Buy GPT-4o API for the cheapest pricing and instant API key.
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Access GPT-4o & Gemini 3.1 Pro via AI API Hub
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