Random port generator
ClientPick a port in a range—see IANA ports for well-known assignments.
About Random port generator
Pick a random TCP port in a min–max range for dev configs and fixtures—local CSPRNG. The interactive transform on this page runs in your browser tab—Toolcore does not need your paste for the core operation described above.
How to use this page
Paste or type in the main workspace, run the primary action from the toolbar, then copy or download the result. Use Load example when the page offers it, or URL prefill (?q= / ?qb=) so agents and tickets open the same input.
Nearby workflows on Toolcore
- TCP & UDP ports — Well-known and common port numbers with IANA-style service names—filter by port, protocol, or keyword—client-side. when headers, identifiers, or reference tables need a sibling check.
- HTTP fetch test — Send GET/POST and other methods from your browser—see status and body; CORS limits apply. when headers, identifiers, or reference tables need a sibling check.
- CIDR calculator (IPv4 & IPv6) — IPv4 or IPv6 CIDR: network, range, mask or prefix size—computed locally in your browser. when headers, identifiers, or reference tables need a sibling check.
- Random integer generator — Uniform integers in a min–max range—optional unique draws, sort, Web Crypto; local only. when headers, identifiers, or reference tables need a sibling check.
Common use cases
- Choose an ephemeral port for a local dev server.
- Draft firewall allow rules with a random high port.
- Generate sample port values for config templates.
Common mistakes to avoid
Using privileged ports without root
Ports below 1024 often need elevated privileges on Unix.
Assuming the port is free
This tool does not scan listeners on your machine.
FAQ
Is the port cryptographically random?
Yes—crypto.getRandomValues selects the index.
Check if a port is in use?
Not on this page—use OS tools after picking a candidate.
Common search terms
Phrases people search for that match this tool. See the full long-tail keyword index.
- random port generator online
- pick random tcp port for dev
- ephemeral port number generator browser
- random port in range tool
More tools
Related utilities you can open in another tab—mostly client-side.
TCP & UDP ports
ClientWell-known and common port numbers with IANA-style service names—filter by port, protocol, or keyword—client-side.
HTTP fetch test
ClientSend GET/POST and other methods from your browser—see status and body; CORS limits apply.
CIDR calculator (IPv4 & IPv6)
ClientIPv4 or IPv6 CIDR: network, range, mask or prefix size—computed locally in your browser.
Random integer generator
ClientUniform integers in a min–max range—optional unique draws, sort, Web Crypto; local only.