# "CDN on Zerops"


## Keywords
cdn, cache, edge, content delivery, static assets, object storage cdn, geo-steering, purge, cache invalidation

## TL;DR
Zerops CDN has 6 global regions with a **fixed 30-day cache TTL** (HTTP Cache-Control headers are ignored by CDN but still affect browsers). Built on Nginx + Cloudflare geo-steering.

## Regions
1. **EU (Prague, CZ)** — Primary + all-region failover
2. **EU (Falkenstein, DE)** — Secondary European
3. **UK (London)**
4. **AU (Sydney)**
5. **SG (Singapore)**
6. **CA (Beauharnois, Canada)**

DNS TTL: 30 seconds. Geo-steering routes to nearest node. EU Prague is fallback if all others down.

## CDN Modes

### Object Storage CDN
- URL: `https://storage.cdn.zerops.app/bucket/path`
- Env var: ``
- Direct from Object Storage through CDN

### Static CDN
- URL: `https://static.cdn.zerops.app/domain.com/path`
- Env var: ``
- For custom domains on static/nginx services
- **Wildcard domains NOT supported**

### API CDN
- Coming soon
- Env var: ``

## Cache Behavior
- TTL: **Fixed 30 days** (not configurable)
- HTTP `Cache-Control` headers: Affect browser caching, **NOT CDN caching**
- Eviction: LRU when storage capacity reached
- First request: Fetched from origin and cached

## Purge Patterns
```
/*            # All content
/dir/*        # Directory contents
/file$        # Specific file (exact match)
/prefix*      # Pattern prefix match
```
Wildcard must be at end. Use `$` suffix for exact file match.

### Purge via zsc
```bash
zsc cdn purge /*              # Purge all cached content
zsc cdn purge /images/*       # Purge directory
zsc cdn purge /style.css$     # Purge exact file
```

## Gotchas
1. **30-day fixed TTL**: Cannot be changed — `Cache-Control: max-age=3600` has no effect on CDN
2. **No wildcard domains on static CDN**: `*.domain.com` is not supported
3. **Purge wildcards at end only**: `/images/*.jpg` is invalid — use `/images/*`

## See Also
- zerops://themes/services — Object Storage service card
- zerops://guides/public-access