Get started with Nostr Connect

Nostr Connect (NIP46) is a remote key access protocol.

If you need continuous access to users' Nostr keys, you have these options:

store private keys in your app (please don't do that!)
use window.nostr (NIP07), which is only available for web apps with a browser extension installed
use Amber or Keystache or other platform-specific solution
use Nostr Connect - a remote key access protocol that works on most platforms and is gaining wide adoption

This guide is for you if you want to implement Nostr Connect.

If you are looking for a more general login with Nostr guide, check out nostrlogin.org

How to get started with Nostr Connect?

Before we start, to test your Nostr Connect client you should get yourself a server first - try nsec.app or nsecbunker.com or Gossip nostr client.

Now, if you're building a web app, the best place to start would be nostr-login or window.nostr.js.

These are drop-in scripts that provide the UI for users to log in with Nostr Connect, while exposing a window.nostr object for your app to work with.

It super easy!

Just call signEvent and other methods on the window.nostr object and these libs will handle the rest.

Because there's actually a lot to handle...

How to implement login with Nostr Connect?

If you just want your own Nostr Connect UI you should probably use NDK or nostr-tools@v2 to avoid implementing the full nip46 protocol yourself.

However, even with one of these libraries, the flow will be quite complex:

ask the user for their bunker URL or nip05 address
show a Loading state to the user when they click Login, establishing a connection will take a while
if nip05 address is entered, fetch the nostr.json info to get remote user pubkey and the bunker relays (that's queryBunkerProfile with nostr-tools, with NDK you just supply the nip05 to the NDKNip46Signer)
if bunker URL is entered, parse it properly to get the remote user pubkey, bunker relays and an optional secret token (example #1, #2) (that's parseBunkerInput with nostr-tool, with NDK you have to do that yourself)
make sure you connect to the specified bunker relays (NDK)
generate the Local keypair, it will be used to sign nip46 requests to the remote user pubkey
create a nip46 client and supply the local keypair privkey and other params to it, that's BunkerSigner with nostr-tools or NDKNip46Signer with NDK
subscribe to auth_url messages, that's onauth callback with nostr-tools or authUrl event with NDKNip46Signer - these are needed for users to confirm the actions you're requesting from their keys
send a connect request, that's BunkerSigner.connect with nostr-tools or NDKNip46Signer.blockUntilReady with NDK
if auth_url message arrives, you are supposed to open a popup browser tab with the provided URL
show users a Please confirm button and only open the popup when they click it, opening without direct user action will get your popups blocked in many browsers
the popup tabs are supposed to be closed automatically when user finishes interacting with them, you don't have to do that yourself
when connect is finished, your connection is established and you're ready to make other methods calls
save the local keypair and other params in persistent storage, reuse them next time your app starts

Wow, we made it!

Well hopefully we didn't miss anything and it actually worked.

How to access keys with Nostr Connect?

Here is what happens next:

you send sign_event or other requests using the nip46 client
auth_url messages might arrive if key storage app needs a confirmation from the user
you should show a non-modal notification to the user saying Please confirm
when user clicks, open the URL provided by auth_url message, opening it without a click will get your popup blocked and users irritated
the popup will be auto-closed, no need to watch it

Cool, we're accessing those keys now!

How to implement signup with Nostr Connect?

Instead, we will use the remote signer pubkey to send a create_account request to the nip46 server.

Here is how it will look with nostr-tools or NDK:

ask the user for their preferred username, and show them a list of nip46 providers - the full username will be name@provider.com
you might fetch the list of providers from the Nostr network, that's fetchBunkerProviders with nostr-tools, but keep in mind - anyone can publish a provider description, and you don't want to send your users to some scammy service, so...
so maybe you start with a static list of good providers, and only fetch from network later, when you add some Web of Trust signals for your users to evaluate the providers
now that user has entered their preferred username and selected a provider - make a nip05 request to check if the username is available
if the name is available, let users click Sign up, show them the Loading state
fetch the remote signer pubkey and bunker relays of the selected provider from their nostr.json?name=_ endpoint
connect to the bunker relays (NDK)
with nostr-tools you will call createAccount and supply the provider info and the onauth callback
with NDK you'll have to create a NDKNip46Signer with remote signer pubkey and then create the create_account request yourself and send it with their rpc object
whenever auth_url message arrives, follow the same logic as above with the Login flow
create_account will return the newly created remote_user_pubkey
with createAccount of nostr-tools, you will get a ready-to-use BunkerSigner object (when they fix an issue)
with NDK you'll have to create a new NDKNip46Signer yourself with the same local keypair and the new remote user pubkey
and don't forget to save the local keypair and remote user pubkey and bunker relays to the persistent storage to reuse later

Now that was really hard, even with a help of some libraries. Hopefully, we get wider and more polished support for create_account method, for now - it is what it is.

How to implement the Nostr Connect client protocol?

This is really out of scope of a Getting started guide (just use libraries), but here are some hints:

when subscribing to the replies from the signer, add the since filter with something like now - 10 seconds threshold, many strfry relays don't actually delete the ephemeral events and will send you old replies
make sure the first parameter for connect method is the remote user pubkey, not local keypair pubkey
make sure you support passing the secret as a second parameter to connect method, some providers only allow connections with a secret
all parameters and all return values of the nip46 method calls are strings, which means you'll have to stringify the event for signEvent, etc
make sure you handle relay disconnects properly - reconnect, and re-subscribe to nip46 replies
make sure you ignore duplicates of auth_url messages, only the first auth_url per method call should be handled
make sure you ignore duplicate replies, only handle the first one
make sure you test with relays dedicated to nip46, general purpose public relays may block ephemeral events or may impose rate limits if you make lots of method calls

How to implement the Nostr Connect server protocol?

Some hints here too:

when subscribing to the replies from the signer, add the since filter with something like now - 10 seconds threshold, many strfry relays don't actually delete the ephemeral events and will send you old replies
make sure you only allow confirmation of new connections without a secret using auth_url pages, do not show connection requests without a secret in other parts of your app, this is a security hole
make sure you handle relay disconnects properly - reconnect, resubscribe
LOTS MORE, TBD.

Still have questions?

Submit an issue for this repo, we will do our best to help. And please submit PRs if you have something to contribute.

nostrband/nostrconnect.org