# 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; actual request cost depends on measured usage. Call it through a compatible KeepRouter endpoint supported by its active route, with the model id `gemini-3.5-flash`.

| Spec | Value |
|---|---|
| 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` |

## Call it via the compatible chat endpoint

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

```bash
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

```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

```js
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](https://deepmind.google/). 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

- [Call Gemini 3.5 Flash with the OpenAI SDK](https://keeprouter.com/use-cases/openai-sdk.md)
- [Use Gemini 3.5 Flash in Claude Code](https://keeprouter.com/use-cases/claude-code.md)

## Related models

- [Gemma 4 31B](https://keeprouter.com/models/gemma-4-31B-it.md) by Google DeepMind — $0.1200 per 1M input tokens and $0.3500 per 1M output tokens
- [Free](https://keeprouter.com/models/free.md) — $0 (free)
- [GLM-4.5](https://keeprouter.com/models/glm-4.5.md) by Zhipu AI — $0.6000 per 1M input tokens and $2.20 per 1M output tokens
- [Doubao 2.0 Pro](https://keeprouter.com/models/doubao-2.0-pro.md) by ByteDance — $1.60 per 1M input tokens and $8.00 per 1M output tokens
- [GLM-4.5 Air](https://keeprouter.com/models/glm-4.5-air.md) by Zhipu AI — $0.2000 per 1M input tokens and $1.10 per 1M output tokens
- [Doubao 2.0 Mini](https://keeprouter.com/models/doubao-2.0-mini.md) by ByteDance — $0.1500 per 1M input tokens and $1.50 per 1M output tokens

## More

- [All models & pricing](https://keeprouter.com/models.md)
- [Quickstart](https://keeprouter.com/docs/quickstart.md)
- [Get an API key](https://keeprouter.com/login?returnTo=%2Fconsole%2Fkeys%3Fmodel%3Dgemini-3.5-flash)

_Catalog facts and prices last changed 2026-08-01._