> ## Documentation Index
> Fetch the complete documentation index at: https://docs.typeauth.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Remain

> Advanced rate limiting mechanism that allows you to set a pool of valid requests at the application level

# TypeAuth Remain Feature

The TypeAuth Remain feature is an advanced rate limiting mechanism that allows you to set a pool of valid requests at the application level. This feature provides a powerful way to manage and distribute API usage across all keys issued by an application.

## How It Works

The Remain feature operates on the principle of a shared pool of requests for an entire application:

1. **Application-Level Pool:** Set a total number of allowed requests for the entire application.
2. **Shared Usage:** All API keys issued by the application draw from this shared pool.
3. **Flexible Management:** The pool can be manually adjusted or automatically replenished using refill policies.

## Key Concepts

* **Shared Resource Pool:** Instead of individual limits per key, there's a collective limit for all keys.
* **Dynamic Allocation:** Requests are consumed from the shared pool as they're made by any valid key.
* **Adaptable Limits:** The pool of remaining requests can be adjusted based on needs or usage patterns.

## Why It's Useful

1. **Global Resource Control:** Manage overall API usage across all users of an application.
2. **Flexible Distribution:** Allow for varied usage patterns among different users without individual restrictions.
3. **Simplified Management:** Adjust limits for all users of an application at once.
4. **Usage Insights:** Gain a clear view of total API consumption for an application.

## Important Feature: Integration with Refill Policies

The Remain feature becomes even more powerful when combined with [Refill](https://docs.typeauth.com/refill) Policies:

* **Automatic Replenishment:** Set up regular increases to the remain pool using daily, weekly, or monthly refills.
* **Maintain Availability:** Ensure a consistent level of available requests over time.
* **Adaptive Capacity:** Automatically adjust to usage patterns and growth.

## Manual Adjustments

In addition to automatic refills, the remain pool can be manually adjusted:

* **Increase Capacity:** Add more requests to the pool for temporary high-demand periods.
* **Decrease Capacity:** Reduce the pool size if usage is lower than expected.
* **One-time Boosts:** Provide extra capacity for special events or promotions.

## Use Cases

1. **SaaS Platforms:**
   Manage API usage across all customers of a specific application or service tier.

2. **Developer Ecosystems:**
   Allocate a shared pool of requests for all third-party developers using your API.

3. **Multi-tenant Applications:**
   Control resource usage across all tenants while allowing flexibility in individual usage patterns.

4. **Seasonal Businesses:**
   Adjust the remain pool based on expected demand fluctuations throughout the year.

5. **Freemium Models:**
   Offer a shared pool of requests for free tier users, encouraging efficient use of resources.

## Benefits of Combining Remain with Refill Policies

1. **Predictable Capacity:** Maintain a consistent level of available requests over time.
2. **Scalable Usage:** Automatically adapt to growing or changing usage patterns.
3. **Efficient Resource Allocation:** Optimize API capacity based on actual usage trends.
4. **Flexible Management:** Combine automatic refills with manual adjustments for optimal control.
5. **Improved Planning:** Better forecast and manage API infrastructure needs.