How much does the Gemini 3.8 Flash API cost?

On FastMetal, Gemini 3.8 Flash is billed per token in yen: ¥128.83 per 1M input tokens and ¥644.15 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.

Can I call Gemini 3.8 Flash with the OpenAI SDK?

Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "gemini-3.8-flash" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.

What is the context window of Gemini 3.8 Flash?

1,048,576 tokens, shared between the prompt and the response.

What do I need to try Gemini 3.8 Flash?

Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.

Back to Models

google/gemini-3-8-flash

Gemini 3.8 Flash

Gemini 3.8 Flash is Google's most intelligent Flash model with significant gains from 3.7 Flash across software engineering, agentic tasks, and multi-step reasoning.

9/2/2026

1,048,576 tokens

Input: ¥128.8292/M

Output: ¥644.1461/M

Try in Chat Get API Key

Specifications

Modalities

Input

text

image

video

file

audio

Output

text

Supported Parameters

include_reasoning

max_tokens

reasoning

reasoning_effort

response_format

seed

stop

structured_outputs

temperature

tool_choice

tools

top_p

Max Output Tokens

65,536

Reasoning Configuration

Default: Thinking on (effort: medium)
Selectable effort levels: high
medium
low
Turning thinking off: Not possible (always thinks)

How to control thinking, and what it costs

Code Examples

curl https://api.fastmetal.ai/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{
    "model": "gemini-3.8-flash",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'

How Gemini 3.8 Flash actually answers

Real responses to our standard prompts, recorded on FastMetal.

Count the number of 'r's in 'strawberry'

Count the number of 'r's in 'strawberry'. Explain your reasoning step by step.

There are **3** 'r's in the word "strawberry". Here is the step-by-step breakdown: 1. **Break the word into its individual letters:** * **s** (1st letter) * **t** (2nd letter) * **r** (3rd letter) — **1st 'r'** * **a** (4th letter) * **w** (5th letter) * **b** (6th letter) * **e** (7th letter) * **r** (8th letter) — **2nd 'r'** * **r** (9th letter) — **3rd 'r'** * **y** (10th letter) 2. **Count the occurrences:** * One 'r' is in the first syllable: "st**r**aw" * Two 'r's are in the second syllable: "be**rr**y" Total: **3**

3.9s response562 output tokens

Debug This Error

I'm getting the following error in my Node.js application: TypeError: Cannot read properties of undefined (reading 'map') at UserList (/app/components/UserList.js:12:25) at renderWithHooks (/app/node_modules/rea…

### The Cause This error occurs because the `users` prop is `undefined` when the component renders, and JavaScript cannot call `.map()` on `undefined`. This typically happens in two common scenarios: 1. **Asynchronous data fetching:** The parent component fetches `users` from an API. On the initial render, the data hasn't arrived yet, so `users` defaults to `undefined`. 2. **Missing prop:** The parent component forgot to pass `users` (e.g., `<UserList />` instead of `<UserList users={data} />`). --- ### How to Fix It Here are the most common ways to resolve this: #### Option 1: Provide a default parameter (Recommended) Set a default value of an empty array (`[]`) for `users`. If `users…

7.1s response1003 output tokens

Code Review

Please review the following Python function and suggest improvements for readability, performance, and best practices: def get_data(url, retries=3): import requests import time for i in range(retries):…

Here is a code review of your function, broken down by issue category, followed by refactored versions. --- ### Key Issues & Areas for Improvement #### 1. Correctness & Error Handling * **Bare `except:` clause:** Catching all exceptions with a bare `except:` is dangerous. It suppresses system exits (`KeyboardInterrupt`, `SystemExit`) and masks programming bugs (like `KeyError` or `NameError`). You should catch specific exceptions, primarily `requests.RequestException`. * **Silent failure returning `[]`:** If all retries fail, returning an empty list makes it impossible for the caller to distinguish between *"the API returned 0 active items"* and *"the network is completely down"*. It is u…

15.1s response2139 output tokens

Compare these answers side by side with other models →

Frequently asked questions

How much does the Gemini 3.8 Flash API cost?: On FastMetal, Gemini 3.8 Flash is billed per token in yen: ¥128.83 per 1M input tokens and ¥644.15 per 1M output tokens, before tax. Usage is drawn from a prepaid balance; there is no subscription or monthly fee.
Can I call Gemini 3.8 Flash with the OpenAI SDK?: Yes. Point base_url at https://api.fastmetal.ai/v1 and pass "gemini-3.8-flash" as the model; existing OpenAI-style code works unchanged, including streaming, tool calls and structured output.
What is the context window of Gemini 3.8 Flash?: 1,048,576 tokens, shared between the prompt and the response.
What do I need to try Gemini 3.8 Flash?: Create an account and add credit; the model is then available both in the browser chat and over the API. There is no contract or minimum spend.