I searched their pub key on Nostr and then went to their profile. They usually have a link to a website where you can send some Sats to whitelist your pub key on their relay.
You can find the paid relay’s pub key in this article.
https://thebitcoinmanual.com/articles/paid-nostr-relay/
Austin
npub1uh…vxevm
2023-02-23 22:40:47
in reply to nevent1q…ydt9
Author Public Key
npub1uhwak9vw0x6k35gd34thn25ccan0elx7kceqdd2k06l35kgvs9gqzvxevmPublished at
2023-02-23 22:40:47Event JSON
{
"id": "216d78582e931b3bf8225cf7e3047bc9b0fce06cada0b48ab77db34d5208ecae",
"pubkey": "e5dddb158e79b568d10d8d5779aa98c766fcfcdeb63206b5567ebf1a590c8150",
"created_at": 1677188447,
"kind": 1,
"tags": [
[
"e",
"4156480d0fa1b8ed087e3013aff69d7f9ea521f3adb2f29ed99e137c9364253c"
],
[
"e",
"c85de7232116eb3d95677c4aee07d5e85cf55db88ca4bde6f6c3f1952550d510"
],
[
"p",
"dc86f6921799e3300e758ea09d1950d1403ce9c0ed97512a5ed4c32ee678d404"
]
],
"content": "I searched their pub key on Nostr and then went to their profile. They usually have a link to a website where you can send some Sats to whitelist your pub key on their relay.\n\nYou can find the paid relay’s pub key in this article. \n\nhttps://thebitcoinmanual.com/articles/paid-nostr-relay/",
"sig": "0c8bc3cd5a7185baf7bc2cb74d65858252eba64bc7060e83a71b53442a3c55d1230021a0ae04bfd3f377ccf5ca284a20035717c9facc1cca385dea59bad1123e"
}