Gemini 3.5 Flash API — pricing & specs

Gemini 3.5 Flash, made by Google DeepMind, accepts text and image input and returns text. On KeepRouter, Gemini 3.5 Flash costs $1.50 per 1M input tokens and $9.00 per 1M output tokens, billed pay-as-you-go with no monthly fee. Call it through a compatible KeepRouter endpoint supported by its active route, with the model id gemini-3.5-flash.

Maker	Google DeepMind
Modality	Text, vision
Input price	$1.50 per 1M tokens
Output price	$9.00 per 1M tokens
Cached input	$0.1500 per 1M tokens
Capabilities	Vision (image input), Chat completions, Streaming where supported, Tool calling where supported
Endpoint	POST /v1/chat/completions or POST /v1/messages (compatible chat routes)
Model id	`gemini-3.5-flash`

How pricing works for Gemini 3.5 Flash

Gemini 3.5 Flash is billed per token — $1.50 per 1M input tokens and $9.00 per 1M output tokens, with cached input at $0.1500 per 1M tokens. The published price is pay-as-you-go, with no monthly fee; actual request cost depends on measured token usage.

Calling Gemini 3.5 Flash on KeepRouter

Point a compatible client at the supported KeepRouter endpoint and set the model to gemini-3.5-flash. KeepRouter preserves the client-facing request shape while handling upstream routing or translation. Use POST /v1/chat/completions or, on compatible chat routes, POST /v1/messages; streaming and tool support depend on the model's active route.

cURL

curl https://keeprouter.com/v1/chat/completions \
  -H "Authorization: Bearer $KEEPROUTER_KEY" -H "Content-Type: application/json" \
  -d '{"model":"gemini-3.5-flash","messages":[{"role":"user","content":"Hello"}]}'

Python

from openai import OpenAI
client = OpenAI(base_url="https://keeprouter.com/v1", api_key="$KEEPROUTER_KEY")
r = client.chat.completions.create(model="gemini-3.5-flash", messages=[{"role":"user","content":"Hello"}])

JavaScript

import OpenAI from "openai";
const client = new OpenAI({ baseURL: "https://keeprouter.com/v1", apiKey: process.env.KEEPROUTER_KEY });
const r = await client.chat.completions.create({ model: "gemini-3.5-flash", messages: [{ role: "user", content: "Hello" }] });

Source and verification boundary

Official Google DeepMind website. KeepRouter's live catalog is authoritative for the customer price and enabled endpoint shown here; the maker remains authoritative for upstream model capabilities and limits.

Guides

Related models

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Doubao 2.0 Pro by ByteDance — $1.60 per 1M input tokens and $8.00 per 1M output tokens
GLM-4.5 Air by Zhipu AI — $0.2000 per 1M input tokens and $1.10 per 1M output tokens
Doubao 2.0 Mini by ByteDance — $0.1500 per 1M input tokens and $1.50 per 1M output tokens

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Catalog facts and prices last changed 2026-08-01.