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

# Projects & Rules

> Understand how projects and rules are structured in Throttlr.

## Projects

A **Project** in Throttlr maps to a single API key. Think of it as one application or service you want to protect.

* Each project has **one API key**
* Rules and logs are scoped to that project
* Deleting a project deletes its API key, all rules, and all logs

### Example project layout

```
Project: "my-saas-backend"
  └── API Key: sk_live_abc123...
      ├── Rule: login_attempt    (5 req / 60s, Fixed Window)
      ├── Rule: send_email       (10 req / 3600s, Fixed Window)
      └── Rule: generate_report  (3 req / 60s, Sliding Window)
```

***

## Rules

A **Rule** defines a rate limit policy. Each rule has:

| Field         | Description                                             |
| ------------- | ------------------------------------------------------- |
| **Name**      | Unique identifier used in SDK calls (e.g. `send_email`) |
| **Limit**     | Max number of requests allowed per window               |
| **Window**    | Duration of the window in seconds                       |
| **Algorithm** | `FIXED_WINDOW` or `SLIDING_WINDOW`                      |

### Rule names are your contract

The rule `name` is the string you pass to `limiter.check()`. If you rename a rule in the dashboard, you must update your code too, or checks will fail.

<Warning>
  Rule names must be **unique per project**. Two rules in the same project cannot have the same name.
</Warning>

***

## Identifiers

An **identifier** is the key you use to track individual entities. It's not stored in the rule itself — you provide it at check time.

```typescript theme={null}
await limiter.check({
  identifier: "user_456",   // tracked independently per rule
  rule: "send_email",
});
```

Each unique combination of `(rule, identifier)` has its own counter in Redis.

***

## One Key Per Project

Throttlr enforces **one API key per project**. This is intentional — it keeps the authentication model simple and clear. If you need to rate limit different services separately, create separate projects.