How to keep track of localhost ports
There are two questions here and they get answered by different tools. What is on 3000 right now? is a question about the running machine, and lsof answers it in a second. What is 4012 for? is a question about a decision you made in March, and nothing that reads the kernel can answer it, because on most days nothing is listening.
Below is what each of the usual answers actually does. Every claim links to the product’s own documentation, and several of these pages end by telling you to keep using the thing.
Coffee Port cannot answer the first question. A web page has no way to see what is bound to a port on your machine, and getting one would mean a daemon on localhost and a hole in the policy that keeps a decrypted ledger from leaving the tab. So this is not a replacement for lsof — it is the other half, and most people want both.
| Tool | What is listening now | A port nothing is bound to | Read the comparison |
|---|---|---|---|
| lsof and netstat | Shows it | Only what is listening | Compare |
| Raycast Port Manager | Shows it | While it is running | Compare |
| VS Code port views | Shows it | While it is running | Compare |
| ngrok | Shows it | Only what is listening | Compare |
| local domains (Herd, Valet, dnsmasq) | Shows it | While it is running | Compare |
| a spreadsheet or a README | Nothing | Remembers | Compare |
| Coffee Port | Nothing — it cannot see your machine | Remembers — that is the whole idea |
Checked . Features and prices move; the sources on each page are the ones to trust.
What Coffee Port is
A ledger for the ports you have claimed. It hands out new ones by rule rather than by guesswork, knows which numbers will waste your afternoon, and keeps the whole thing end-to-end encrypted — the server holds ciphertext and never a port number.
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