Nostr relay checker

What a relay checker actually tests

A Nostr relay is a websocket server, and there are two useful things you can learn about one from the outside. The first is its self description: NIP-11 defines a JSON document every well behaved relay serves over HTTPS, listing its name, contact, software, version, supported NIPs and limits like maximum message size or required proof of work. The second is how it behaves in practice: whether it accepts a websocket connection at all, and how long that takes from where you are sitting.

This checker does both. It fetches the NIP-11 document and opens a real websocket to time the handshake, so the latency number reflects your actual network path to the relay, not a data center's.

How to read the results

Latency under about 150 milliseconds feels instant in a client. Numbers a few times higher are normal across continents, which is exactly why picking relays near you matters, and why Azzamo runs relays in the EU, US and Asia Pacific rather than one region only.

The supported NIPs list tells you what features work on that relay. If you rely on long form articles, look for NIP-23 handling. If a relay does not serve a NIP-11 document at all, it can still work fine, but it tells you nothing about itself, which is worth knowing before you trust it with your notes.

A relay that fails both the document fetch and the websocket test is down for you. That might be the relay itself, or a network block between you and it. Testing from another connection settles which.

Choosing relays worth keeping

A good relay list balances proximity, reliability and redundancy. Keep a couple of relays close to you for speed, at least one large well connected relay for reach, and never rely on a single one. Relays disappear without warning; your notes should not.

Checking a relay before adding it takes ten seconds and saves debugging later. If it responds slowly from your location today, it will feel slow in your client every day.

One more habit worth building: recheck your relays every few months. Software gets updated, policies change, and a relay that was fast when you added it can degrade quietly. Since your relay list travels with your profile, a five minute review keeps your reach healthy without touching anything else in your setup.