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

# FAQ

> Frequently asked questions about the Essal developer platform and API.

## General

**What is the Essal API?**

The Essal API is a unified REST API that provides programmatic access to all six apps in the Essal suite — Office, Access, Sales, Careers, Project, and Guard. All apps share a common authentication layer, data model, and pagination format.

**Do I need to use all six apps?**

No. Each app is independent. You can use the API for only the apps you need. Apps can be enabled or disabled per workspace.

**Is there a free tier?**

The sandbox environment is free and available to all registered accounts. Production usage requires a paid workspace plan. See [essal.cloud/pricing](https://essal.cloud/pricing) for plan details.

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## Authentication

**What authentication methods are supported?**

Essal supports API keys (for server-to-server integrations) and OAuth 2.0 with PKCE (for user-facing apps). See [Authentication](/getting-started/authentication).

**How do I rotate an API key?**

API keys cannot be edited after creation. Generate a new key in **Settings → Developer → API Keys**, update your integration, then delete the old key.

**Can I use a single API key across all apps?**

Yes. An API key is scoped to a workspace and can carry permissions for any combination of apps. Assign only the scopes your integration actually needs.

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## Apps & Data

**How do the six apps share data?**

Apps share data through the Essal Core API using typed cross-app references (`linked_resources`). For example, a Project task can reference a Sales deal or an Office document. See [Data Model](/concepts/data-model).

**How do I link records between apps?**

Add a `linked_resources` array to any entity with `{ "type": "app.entity_type", "id": "entity_id" }`. Both apps must be enabled in the workspace.

**Are deleted records recoverable?**

Deleted records are soft-deleted by default and retained for 30 days. To recover a soft-deleted record, update its status to `active`. Hard-deleted records (`?hard=true`) are permanent.

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## Webhooks

**Why is my webhook endpoint receiving duplicate events?**

Essal delivers events with at-least-once guarantees. Retry deliveries may result in duplicates. Use the event `id` field to deduplicate in your handler.

**How do I test webhooks locally?**

Use a tunnelling tool such as ngrok to expose your local server, then register your tunnel URL as a webhook endpoint against the sandbox environment.

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## Rate Limits

**What happens when I hit the rate limit?**

The API returns `429 Too Many Requests` with a `Retry-After` header indicating how many seconds to wait. Official SDKs handle this automatically.

**Can I increase my rate limits?**

Enterprise plans support higher rate limits. Contact [support.essal.cloud](https://support.essal.cloud) to discuss your needs.