diff --git a/include/ircd/m/dbs.h b/include/ircd/m/dbs.h
index 0925e9c5b..40ae5dcd8 100644
--- a/include/ircd/m/dbs.h
+++ b/include/ircd/m/dbs.h
@@ -60,6 +60,7 @@ namespace ircd::m::dbs
 
 	// [SET (txn)] Basic write suite
 	string_view write(db::txn &, const event &, const write_opts &);
+	void blacklist(db::txn &, const event::id &, const write_opts &);
 }
 
 struct ircd::m::dbs::write_opts
diff --git a/ircd/m/dbs.cc b/ircd/m/dbs.cc
index 4c4d59e46..54a2930f9 100644
--- a/ircd/m/dbs.cc
+++ b/ircd/m/dbs.cc
@@ -102,6 +102,24 @@ namespace ircd::m::dbs
 	static string_view _index_ephem(db::txn &, const event &, const write_opts &);
 }
 
+void
+ircd::m::dbs::blacklist(db::txn &txn,
+                        const event::id &event_id,
+                        const write_opts &opts)
+{
+	db::txn::append
+	{
+		txn, event_bad,
+		{
+			opts.op,
+			string_view{event_id},
+			opts.idx != uint64_t(-1) && opts.op == db::op::SET?
+				byte_view<string_view>(opts.idx):
+				string_view{}
+		}
+	};
+}
+
 ircd::string_view
 ircd::m::dbs::write(db::txn &txn,
                     const event &event,