diff --git a/doc/standards/op_return-prefix-guideline.md b/doc/standards/op_return-prefix-guideline.md
--- a/doc/standards/op_return-prefix-guideline.md
+++ b/doc/standards/op_return-prefix-guideline.md
@@ -20,6 +20,7 @@
 | 64726f70            | Airdrop           | Bitcoin ABC                         | ecash:pqnqv9lt7e5vjyp0w88zf2af0l92l8rxdg2jj94l5j | https://cashtab.com/                                          | `<64726f70> <tokenId of airdrop recipients>` |
 | 2E786563            | Namespace Alias   | Bitcoin ABC                         | ecash:pqnqv9lt7e5vjyp0w88zf2af0l92l8rxdg2jj94l5j | See ../standards/ecash-alias.md                               | See spec                                     |
 | 50415900            | PayButton         | Blockchain Ventures                 | ecash:qrmm7edwuj4jf7tnvygjyztyy0a0qxvl7quss2vxek | See ../standards/paybutton.md                                 | See spec                                     |
+| 63686174            | eCash Chat        | Bitcoin ABC                         | ecash:qz9aa3yeuspe569xqtmn0f8aaxwmdjz4l58z6hzv9u | N/A                                                           | `<63686174> <utf8 msg>`                      |
 
 ---