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

# Licensing

> How SendyKit self-hosted licensing works

## Overview

SendyKit self-hosted uses **EDD Software Licensing-powered license verification**. Your license key determines your edition (Standard or Pro) and unlocks the corresponding features. Human checkout, licensing, and subscription mechanics run through Easy Digital Downloads on sendykit.dev.

## How It Works

<Steps>
  <Step title="Purchase">
    Buy a license at [sendykit.dev/pricing](https://sendykit.dev/pricing). You receive a license key: `sk_lic_xxxxxxxxxxxxx`
  </Step>

  <Step title="Install">
    ```bash theme={null}
    curl -sSL https://install.sendykit.dev | bash
    ```

    The installer prompts for your license key and validates it.
  </Step>

  <Step title="Validate">
    On first launch, the Go binary contacts the SendyKit licensing API to verify your key and download your entitlements (edition, features, metered service access).
  </Step>

  <Step title="Run">
    The binary caches your entitlements locally. Weekly heartbeat checks for updates. 30-day offline grace if the licensing server is unreachable.
  </Step>
</Steps>

## Safety Guarantees

We take these seriously. SendyKit will **never** brick your installation.

| Guarantee                | What It Means                                                                                                                                |
| ------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------- |
| **Fail-open**            | If the licensing server is down, your binary keeps running with cached entitlements. It never stops working.                                 |
| **30-day offline grace** | After 30 days without a heartbeat: you see a warning banner. Not a shutdown. All features keep working.                                      |
| **No data exfiltration** | Zero customer data leaves your server. No emails, subscriber lists, campaign content, API keys, or PII are ever transmitted.                 |
| **Transparent logging**  | Every phone-home request is logged to `sendykit.log`. You can audit exactly what's sent.                                                     |
| **Auditable payload**    | The heartbeat sends only: `license_key`, `version`, `os`, `arch`, `subscriber_tier` (a range, not exact count), `uptime_days`. Nothing else. |
| **Fully disable-able**   | Set `SENDYKIT_OFFLINE=true` to disable all phone-home. License cached indefinitely. No nag screens.                                          |
| **No kill switch**       | The binary never self-disables. Even with an expired or revoked license: warning banner only. All features keep working.                     |
| **Open heartbeat spec**  | The heartbeat format is documented here so you can firewall-verify what's transmitted.                                                       |

## Heartbeat Payload

```json theme={null}
{
  "license_key": "sk_lic_xxxxx",
  "version": "1.2.0",
  "os": "linux",
  "arch": "amd64",
  "subscriber_tier": "1k-5k",
  "feature_flags_hash": "a1b2c3d4",
  "uptime_days": 42
}
```

<Warning>
  The `subscriber_tier` is a range bucket (e.g., "1k-5k"), not an exact count. We never know your actual subscriber count.
</Warning>

## Editions

| Feature                   | Standard | Pro |
| ------------------------- | -------- | --- |
| REST API (125 endpoints)  | ✅        | ✅   |
| CLI (240+ commands)       | ✅        | ✅   |
| Analytics Intelligence    | ✅        | ✅   |
| Health Doctor (68 checks) | ✅        | ✅   |
| SMTP Overlay              | ✅        | ✅   |
| Audit Trail               | ✅        | ✅   |
| Admin UI (7 pages)        | ✅        | ✅   |
| Visual Editor (GrapeJS)   | ✅        | ✅   |
| AI Authoring              | —        | ✅   |
| Sequences & Funnels       | —        | ✅   |
| Automations               | —        | ✅   |
| Priority Support          | —        | ✅   |
| White Label               | —        | ✅   |

## Metered Add-Ons

Self-hosted customers can optionally purchase metered services that run through SendyKit's infrastructure:

| Service                   | What                                                                                                 | Pricing            |
| ------------------------- | ---------------------------------------------------------------------------------------------------- | ------------------ |
| **SMTP Pool Overflow**    | When your SES quota is exhausted, SendyKit routes overflow emails through our managed SMTP providers | \$3-5/1000 emails  |
| **AI Content Credits**    | AI requests proxied through SendyKit's API — no need for your own OpenAI/Anthropic key               | \$0.002/generation |
| **Deliverability Shield** | Continuous DNS/reputation monitoring from SendyKit's servers                                         | \$49/year          |
| **Priority Support**      | Faster response times, dedicated support queue                                                       | \$99/year          |

Usage is tracked natively by SendyKit. Human purchases and add-on checkout run through EDD on sendykit.dev, using the card attached to your customer account when applicable.

## Offline Mode

For air-gapped or restricted environments:

```bash .env theme={null}
SENDYKIT_OFFLINE=true
SENDYKIT_LICENSE_KEY=sk_lic_xxxxxxxxxxxxx
```

In offline mode:

* No network requests to SendyKit servers
* License validated from local cache only
* Metered add-ons (SMTP pool, AI credits) unavailable
* All installed features work normally
* No update notifications