RSZ is a URL shortening service designed for developers and teams who need reliable, ultra-low latency short links with custom domains.
How it works
When you shorten a URL with RSZ, the link resolves at edge. There's no central server to become a bottleneck. That makes RSZ fast, really fast. Typical redirect times are just ~56ms anywhere in the world.
Key features
Custom domains
Use your own domain (like go.yourcompany.com) for branded short links. RSZ handles TLS certificate provisioning automatically. Most URL shorteners either don't support custom domains or charge premium prices for them.
Flexible expiration
Links can be configured with:
- Expiration time — when the link stops redirecting (default: 30 days)
- Reservation time — how long the short code is reserved even after expiration (default: 90 days)
- Click lifetime — auto-extend expiration when the link is clicked (default: 5 days)
Links can also be set to never expire.
Custom paths
Choose your own path (go.example.com/spring-sale) or let RSZ generate a short code. Custom paths are useful for memorable, branded links.
Bulk shortening
Shorten thousands of links in a single API request instantly. All are live immediately.
Team workspaces
Accounts support multiple users with role-based access. Invite team members by email. This is useful for marketing teams or organizations where multiple people need to create and manage links.
API access
Every domain gets an API key for programmatic link creation. The API supports:
- URL shortening with custom options
- Link info retrieval
- Domain configuration
Per-domain settings
Each domain can have its own:
- Default redirect URL (for unknown paths)
- robots.txt content
- API key (can be rotated)
Comparison with other services
| Feature |
RSZ |
Bitly |
TinyURL |
Rebrandly |
| Typical Latency |
56ms |
95ms |
65ms |
65ms |
| Custom domains |
Yes |
Paid plans |
Paid plans |
Paid plans |
| Team accounts |
Yes |
Paid plans |
No |
Paid plans |
| Link expiration |
Configurable |
Limited |
No |
Limited |
| Click-extend lifetime |
Yes |
No |
No |
No |
| Custom paths |
Yes |
Yes |
Paid |
Yes |
| API access |
Yes |
Yes |
Limited |
Yes |
Note: The latency number we are quoting is best performance after repeated requests to the other services to get their best fully cached time. In our testing bitly and rebrandly respond in over 400ms on the first request.
What "edge-based" means
RSZ uses a pure edge serving without any origin server (really none at all):
- User clicks short link
- Request goes to nearest edge location (100+ worldwide)
- Edge resolves the link locally - including an edge based DB lookup.
- Redirect response sent immediately
There is no "cache miss" long latency DB lookup for the first redirect in a zone.
This matters for:
- Latency — Redirects complete faster because there's no round-trip to a distant server
- Reliability — No single point of failure; if one data center has issues, others continue working
- Scale — Traffic spikes don't cause slowdowns because load distributes automatically
When RSZ makes sense
RSZ is a good fit if you:
- Want the absolute fastest redirects globally
- Need programmatic link creation via API
- Need custom branded domains for short links
- Have a team that needs to manage links together
- Want control over link expiration behavior
Technical details
RSZ runs on Fastly's Compute@Edge platform using fully compiled web assembly in c++. The resizing records are served from a local KV store. Our typical server response times are ~7ms. The 56ms total latency will be DNS lookup, the time to negotiate TLS and the 10ms each way that it takes packets to make it from typical urban residential internet to a local fastly POP.
Someday someone may make a url shortener as fast as RSZ, but we doubt its possible to make one much faster.
The API uses standard REST conventions with JSON request/response bodies. See the API documentation for details.
Email questions and comments to rafael@rsz.io
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