# Billing Guide

This guide explains how billing works for the Serika.dev Customer API, including pricing, usage calculation, and account management.

## Billing Models

The Serika.dev Customer API offers two types of accounts:

1. **Free Accounts**: Limited access to models and features with usage caps.
2. **Accounts with Billing**: Full access to all models and features with usage-based billing.

## Setting Up Billing

To set up billing for your API usage:

1. Log in to your [Serika.dev Developer Dashboard](https://developers.serika.dev).
2. Navigate to the **Billing** section.
3. Click **Set Up Billing**.
4. Follow the prompts to enter your payment information.
5. Once billing is set up, your API keys will automatically have access to premium features.

## Usage Metering

### Text Generation

Text generation is metered based on the number of tokens used. A token is approximately 4 characters or 0.75 words in English.

Usage is calculated as the sum of:
- **Input tokens**: The messages you send in your request.
- **Output tokens**: The completions generated by the API.

### Image Generation

Image generation is billed at a fixed rate per image, regardless of prompt length.

## Viewing Your Usage

To view your API usage:

1. Log in to your [Developer Dashboard](https://developers.serika.dev).
2. Click on **API Usage**.
3. You can view usage statistics by time period, API key, and endpoint.

## Pricing

### Free Tier

- No free API tier; only limited character information is available without billing.

### Premium Tier

- Full access to all models, including premium models like `google/gemini-3-pro-preview` and `anthropic/claude-3.5-sonnet`.
- Increased token limits.
- Pay-as-you-go pricing for text and image generation.
- Higher rate limits.

## Payment and Billing Cycles

- Billing is handled securely through Stripe.
- You are billed monthly for your actual usage.
- Invoices are generated on the 1st of each month for the previous month's usage.
- You can view your invoice history in the **Billing** section.

## Managing Your Billing

### Setting Usage Limits

To avoid unexpected charges, you can set usage limits:

1. Navigate to the **Billing** section in the dashboard.
2. Click **Usage Limits**.
3. Set your desired monthly spending limit.
4. When your usage reaches this limit, API requests will be rejected until the next billing cycle or until you increase the limit.