Gemini 3.1 Pro API: Pricing, Context & Alternatives (2026)

2M-token context. $1.25/$10 per 1M. Google's answer to Claude Opus 4.7. Is it the best long-context value money can buy?

Google released Gemini 3.1 Pro on April 10, 2026. It's the quietest of the frontier launches this spring โ€” no Twitter drama, no demo videos of the model "feeling emotions." Just numbers:

If you process long documents, this changed the math.

Pricing deep-dive

ModelInput / 1MOutput / 1MCached InputContext
Gemini 3.1 Pro$1.25$10.00$0.312,000,000
Gemini 3.1 Flash$0.10$0.40$0.0251,000,000
Claude Opus 4.7$5.00$25.00$0.501,000,000
GPT-5.5$5.00$30.00$0.625400,000
DeepSeek V4 Pro$0.27$1.10$0.068128,000

Gemini 3.1 Pro sits in a sweet spot: frontier-ish quality at sub-frontier pricing, with a context window that eats the competition for lunch.

And Gemini 3.1 Flash at $0.10/1M input is genuinely the cheapest quality model from a hyperscaler โ€” competitive with DeepSeek V3.2 on price, with 1M context.

๐ŸŒ Gemini 3.1 Pro via OpenAI SDK

One key routes to Gemini + GPT + Claude + DeepSeek. No Google Cloud setup.

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When Gemini 3.1 Pro wins

1. Long-document workloads (50K+ tokens)

Legal review, research paper synthesis, codebase Q&A, SEC filings โ€” anywhere you'd previously chunk-and-retrieve, you can now just paste the whole thing. Gemini's 2M window at $1.25/1M input is what makes this economical.

A 1M-token ingest = $1.25 on Gemini vs $5.00 on Opus vs ~$20 on GPT-5.5 (split across calls). That's a 4-16x saving before you even get to output.

2. Multimodal (video, audio)

Gemini is the model for native video understanding. It ingests video frame-by-frame, understands audio tracks, and reasons about temporal events. If your product processes user-uploaded videos, GPT/Claude aren't in the race yet.

3. Structured output at scale

Gemini's JSON mode is schema-enforced (similar to GPT-5.5 strict mode) and notably cheaper. For any pipeline that extracts structured data from messy inputs, Gemini Pro or Flash is usually the right pick.

When Gemini 3.1 Pro loses

Coding

Gemini 3.1 Pro scores 65% on SWE-Bench Verified vs Opus 4.7's 73.8%. It's a noticeably weaker coding agent. For IDE copilots or repo refactoring, Opus or DeepSeek V4 are better choices.

Instruction following in edge cases

Gemini still occasionally ignores length constraints or format instructions when the context is >500K tokens. Opus 4.7 is tighter on this.

Safety-layer over-refusals

Gemini's safety filter is stricter than Claude's or GPT's. Legal/medical/security prompts get false-refused more often. You can tune it via safetySettings, but not all aggregators expose that parameter.

How to access Gemini 3.1 Pro

Option A: Google AI Studio (direct)

Free tier available, generous rate limits. Required: Google account, and in most cases a credit card for the paid tier. Geographic availability varies โ€” some regions see the API blocked.

pip install google-generativeai

import google.generativeai as genai
genai.configure(api_key="AIza...")

model = genai.GenerativeModel("gemini-3.1-pro")
response = model.generate_content("Summarize this 500K-token PDF: ...")
print(response.text)

Option B: Vertex AI (enterprise)

Required: Google Cloud project, billing enabled, IAM roles. More setup, but you get per-project quotas, logging, and data residency controls. Best for regulated industries.

Option C: OpenAI-compatible gateway

If you already use the OpenAI SDK (or LangChain/LlamaIndex with OpenAI defaults), a gateway like NovAI exposes Gemini 3.1 Pro as just another model:

from openai import OpenAI
client = OpenAI(api_key="sk-novai-...", base_url="https://aiapi-pro.com/v1")

response = client.chat.completions.create(
    model="gemini-3.1-pro",
    messages=[{"role": "user", "content": "..."}],
)

No GCP project, no new SDK, same auth flow for every model you use.

Benchmark summary

BenchmarkGemini 3.1 ProOpus 4.7GPT-5.5
MMLU-Pro81.4%82.7%83.1%
GPQA Diamond84.2%85.9%87.3%
SWE-Bench Verified65.0%73.8%71.2%
AIME 202689.5%92.0%94.1%
NIAH @ 900K tokens97.8%99.2%n/a (out of window)
Video understandingSOTAn/apartial

Add Gemini 3.1 Pro to Your Stack

OpenAI-compatible API. One key for Gemini + Opus + GPT + DeepSeek. $0.50 free credit, no credit card.

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Decision matrix

WorkloadPick
Process a single 500K+ token documentGemini 3.1 Pro โ† unique value
Video or audio analysisGemini 3.1 Pro โ† unique value
Cheap bulk classification / extractionGemini 3.1 Flash or DeepSeek V3.2
Code generation at production qualityOpus 4.7 or DeepSeek V4
Strict JSON at scaleGPT-5.5 or Gemini 3.1 Pro
Marketing copy / creativeGPT-5.5

Bottom line

Gemini 3.1 Pro isn't trying to be the best at everything โ€” it's trying to own long-context and multimodal. On both it succeeds, and the pricing is aggressive enough that for those workloads it's now the default. For coding, stick with Opus/DeepSeek. For creative, stick with GPT-5.5. For reading a 700-page PDF and asking questions about it? Gemini wins on quality-per-dollar by a mile.

Pair with TokenScope to see exact token counts (Gemini's tokenizer is different from GPT's โ€” same prompt often ~15% fewer tokens).

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Gemini 3.1 Pro ยท 2M context ยท NovAI API gatewayGet Free API Key โ†’