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PreviewAdded 30 Aug 2026Google

Gemini 3.1 Pro (preview) API

Google's newest Pro tier, shipped as a preview.

Open playgroundView API docs

Model spec

Input
$2.00per 1M tokens
Output
$12.00per 1M tokens
Context
1.05M
Max output
66K

Prompts over 200K tokens bill at $4.00 / $18.00.

Model ID

OpenAI-compatible · api.companyfabric.com/v1

Replaces Gemini 2.5 Pro. Same endpoint, same key, only the model id changes.

Overview

About Gemini 3.1 Pro (preview)

Google's newest Pro tier, shipped as a preview. Every model on CompanyFabric shares the same API key, billing balance, and rate-limit envelope, one integration covers the entire library.

Facts

At a glance

Availability

Preview

Added 30 Aug 2026

Pricing

$2.00 in · $12.00 out

Per 1M tokens, metered exactly per call

Context window

1.05M tokens

Up to 66K tokens out

Commercial use

See license

Commercial output use permitted per Google terms.

Variants

All endpoints

Gemini 4 Argon

$2/Mtok in

Google DeepMind's frontier model for long-horizon coding, legal, finance and science work, #1 on the Vals Index at launch. Introductory price until 30 November.

Chat Completions

Gemini 3.7 Flash

$0.75/Mtok in

Google's current fast model, million-token context.

Chat Completions

Gemini 3.5 Flash

$1.5/Mtok in

The previous stable Flash, still current for most work.

Chat Completions

Gemini 2.5 Pro

Retired$1.25/Mtok in

Google's stable Pro tier, the non-preview reasoning model.

Chat Completions

Gemini 2.5 Flash

Retired$0.3/Mtok in

Long-context workhorse on the stable 2.5 line.

Chat Completions

Gemini 3.1 Pro (preview)

Preview$2/Mtok in

Google's newest Pro tier, shipped as a preview.

Chat Completions

Gemini 3 Flash (preview)

Preview$0.5/Mtok in

The Gemini 3 Flash preview line.

Chat Completions

Gemini 3.8 Flash

$0.75/Mtok in

Google's most capable Flash model, built for long-horizon software engineering and autonomous agents.

Chat Completions

Gemini 3.6 Flash

$0.75/Mtok in

The previous-generation Flash, balancing speed and multimodal work across everyday agentic tasks.

Chat Completions

Gemini 3.5 Flash-Lite

$0.3/Mtok in

Cost-efficient Gemini for high-volume agentic work, translation and simple data processing.

Chat Completions

Gemini 3.1 Flash-Lite

$0.25/Mtok in

Google's cheapest text model here, for high-volume classification and extraction.

Chat Completions

Quickstart

How to use the Gemini 3.1 Pro (preview) API

  1. 1

    Create a free CompanyFabric account, starter credits are included, no card required.

  2. 2

    Copy your API key from the dashboard. One key covers every model in the library.

  3. 3

    Point any OpenAI SDK at api.companyfabric.com/v1 and set model to "google/gemini-3-1-pro-preview".

  4. 4

    Read the exact metered cost of the call from the response, the same number shown in the playground.

Use cases

What teams build with it

Agents & copilots

Drive agent loops, tool calls, and user-facing assistants over the OpenAI-compatible endpoint.

agentstool useassistants

Content pipelines

Summarization, rewriting, and structured generation at metered per-token cost.

contentsummarization

Extraction & classification

Turn unstructured input into typed JSON with schema-constrained output.

extractionjson mode

Get better output

Prompting tips

  • State the output format before the task, models follow contracts declared early.
  • Few-shot beats description: two worked examples outperform a paragraph of rules.
  • Cap output length explicitly when cost matters; output tokens dominate most bills.

Exact, metered, prepaid

Gemini 3.1 Pro (preview) pricing

Gemini 3.1 Pro (preview) pricing is per token: $2 / M input · $12 / M output. Output tokens cost 6× input tokens, so long generations, not long prompts, are what actually drive most bills. A typical call with a 2k-token prompt and a 1k-token answer costs about $0.0160.

Every call is metered exactly and attributed to your key, the dashboard, the API usage response, and your invoice all read from the same ledger row. Cap any key's monthly spend with a budget cap, and bring your own provider key (BYOK) at 0% platform fee if you already have a direct contract.

EndpointTypePrice
Gemini 4 ArgonChat$2 / M input · $10 / M output · $0.1 / M cached input
Gemini 3.7 FlashChat$0.75 / M input · $3.75 / M output
Gemini 3.5 FlashChat$1.5 / M input · $9 / M output
Gemini 2.5 ProChat$1.25 / M input · $10 / M output
Gemini 2.5 FlashChat$0.3 / M input · $2.5 / M output
Gemini 3.1 Pro (preview)Chat$2 / M input · $12 / M output
Gemini 3 Flash (preview)Chat$0.5 / M input · $3 / M output
Gemini 3.8 FlashChat$0.75 / M input · $3.75 / M output
Gemini 3.6 FlashChat$0.75 / M input · $3.75 / M output
Gemini 3.5 Flash-LiteChat$0.3 / M input · $2.5 / M output
Gemini 3.1 Flash-LiteChat$0.25 / M input · $1.5 / M output

Starter credits

Use Gemini 3.1 Pro (preview) free

Your CompanyFabric starter credits cover your first Gemini 3.1 Pro (preview) calls at no cost, create a free account, no card required, and the credits apply to Gemini 3.1 Pro (preview) and every other model on the key. When they run out, prepaid credits or BYOK (0% fee) take over with no plan to pick.

All ways to use AI models free →

Production-grade

Code samples

import OpenAI from "openai"

const client = new OpenAI({
  baseURL: "https://api.companyfabric.com/v1",
  apiKey: process.env.COMPANYFABRIC_API_KEY,
})

const res = await client.chat.completions.create({
  model: "google/gemini-3-1-pro-preview",
  max_tokens: 1024,
  temperature: 0.7,
  messages: [{ role: "user", content: "Say hello from the fabric." }],
})

console.log(res.choices[0].message.content)

Playground

Try it in the browser

Playground$2 in / $12 out per 1M tokens

Comparisons

Gemini 3.1 Pro (preview) vs the alternatives

Gemini 3.1 Pro (preview) vs Claude Opus 4.6

Gemini 3.1 Pro (preview) and Claude Opus 4.6 compete for the same text workloads. Both run behind the same CompanyFabric key at exact metered prices, A/B them on your real prompts and let the outputs decide, then switch with a one-line change.

Full comparison: Gemini 3.1 Pro (preview) vs Claude Opus 4.6 →

Gemini 3.1 Pro (preview) vs GPT-5.5

Gemini 3.1 Pro (preview) and GPT-5.5 compete for the same text workloads. Both run behind the same CompanyFabric key at exact metered prices, A/B them on your real prompts and let the outputs decide, then switch with a one-line change.

Full comparison: Gemini 3.1 Pro (preview) vs GPT-5.5 →

Compare

Gemini 3.1 Pro (preview) head to head

Gemini 3.1 Pro (preview)vsClaude Sonnet 4.5Gemini 3.1 Pro (preview)vsClaude Opus 4.6Gemini 3.1 Pro (preview)vsGPT-5.5Gemini 3.1 Pro (preview)vsClaude Fable 5Gemini 3.1 Pro (preview)vsClaude Opus 5Gemini 3.1 Pro (preview)vsDeepSeek V4 Pro

FAQ

Frequently asked questions

How much does the Gemini 3.1 Pro (preview) API cost?

$2 / M input · $12 / M output. Every call is metered exactly and shown before you run it.

How do I get a Gemini 3.1 Pro (preview) API key?

Create a CompanyFabric account, and one key unlocks Gemini 3.1 Pro (preview) and every other model in the library. Free starter credits are included, no subscription, no card required to try it.

Why use Gemini 3.1 Pro (preview) on CompanyFabric instead of going direct?

One key, one prepaid balance, and one rate-limit envelope across the whole library, at pricing at parity with or below the direct API. Model switching is a one-line change, and BYOK routing is 0% fee.

Is the API OpenAI-compatible?

Yes, point any OpenAI SDK at api.companyfabric.com/v1 and set model to "google/gemini-3-1-pro-preview".

Can I use the output commercially?

Commercial output use permitted per Google terms.

How does billing work?

Prepaid credits via card, or BYOK with your own provider keys at 0% platform fee. No subscription required; balances never expire.

Provider

About Google

Google publishes the gemini family. Also in this family: Gemini 4 Argon, Gemini 3.7 Flash, Gemini 3.5 Flash, Gemini 2.5 Pro, Gemini 2.5 Flash, Gemini 3 Flash (preview), Gemini 3.8 Flash, Gemini 3.6 Flash, Gemini 3.5 Flash-Lite, Gemini 3.1 Flash-Lite. License: Commercial output use permitted per Google terms.

One key. Every model. Exact prices.

Run Gemini 3.1 Pro (preview) with free starter credits. Free starter credits included, no subscription required.

Get your API keyBrowse all models