This can be done with inbox forwarding or special activities ([FEP-171b](https://codeberg.org/fediverse/fep/src/branch/main/fep/171b/fep-171b.md ) or [FEP-1b12](https://codeberg.org/fediverse/fep/src/branch/main/fep/171b/fep-171b.md )).
Selective relays may be used for other things though. There is https://github.com/dtp-mstdn-jp/selective-relay that apparently can filter activities by hashtags, domains and number of attachments
silverpill
npub19y…5wysk
2026-09-30 08:38:51 UTC
in reply to nevent1q…494l
Author Public Key
npub19yg7mshq9vdtvvcm48svw03cmzewue4jug62cltnleh3y78khz5sm5wyskSeen on
wss://relay.momostr.pinkPublished at
2026-09-30 08:38:51 UTCEvent JSON
{
"id": "9bb488b4ec003ee1e80d686c20177cae1dc17af12b7be00b1535c0e7d2a2d806",
"pubkey": "2911edc2e02b1ab6331ba9e0c73e38d8b2ee66b2e234ac7d73fe6f1278f6b8a9",
"created_at": 1790757531,
"kind": 1,
"tags": [
[
"p",
"7e1fdb91d317744a848bb50e9733629eaa057e16060d070f2073bccc174dc7d1"
],
[
"p",
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],
[
"p",
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],
[
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"",
"root",
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],
[
"p",
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],
[
"e",
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"",
"reply",
"6a7465ca468ca96d9d0b0d71c320faa2bf1cad19843a32bda1b632da688b2929"
],
[
"proxy",
"https://mitra.social/objects/01a0f177-6fb5-7960-bbec-3f4ec2126aea",
"activitypub"
],
[
"L",
"pink.momostr"
],
[
"l",
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"pink.momostr"
],
[
"-"
]
],
"content": "This can be done with inbox forwarding or special activities ([FEP-171b](https://codeberg.org/fediverse/fep/src/branch/main/fep/171b/fep-171b.md ) or [FEP-1b12](https://codeberg.org/fediverse/fep/src/branch/main/fep/171b/fep-171b.md )).\n\nSelective relays may be used for other things though. There is https://github.com/dtp-mstdn-jp/selective-relay that apparently can filter activities by hashtags, domains and number of attachments",
"sig": "c5527c50f76243645ca7bcc1a1c4568c535613b436d0a554d41d3805d0679e322e87ddb2f8c8daac5d8646307dd69a4d83234d362d41e0962f154ea00108e092"
}