diff --git a/src/stratifier.c b/src/stratifier.c
index 2b23c5e7..a90a167f 100644
--- a/src/stratifier.c
+++ b/src/stratifier.c
@@ -299,6 +299,10 @@ struct stratifier_data {
 
 	/* Serialises sends/receives to ckdb if possible */
 	mutex_t ckdb_lock;
+	/* Protects sequence numbers */
+	mutex_t ckdb_msg_lock;
+	/* Incrementing sequence number */
+	int ckdb_seq;
 
 	bool ckdb_offline;
 
@@ -611,12 +615,18 @@ static char *status_chars = "|/-\\";
 
 /* Absorbs the json and generates a ckdb json message, logs it to the ckdb
  * log and returns the malloced message. */
-static char *ckdb_msg(ckpool_t *ckp, json_t *val, const int idtype)
+static char *ckdb_msg(ckpool_t *ckp, sdata_t *sdata, json_t *val, const int idtype)
 {
-	char *json_msg = json_dumps(val, JSON_COMPACT);
+	char *json_msg;
 	char logname[512];
 	char *ret = NULL;
 
+	/* Set the atomically incrementing sequence number */
+	mutex_lock(&sdata->ckdb_msg_lock);
+	json_set_int(val, "seq", sdata->ckdb_seq++);
+	mutex_unlock(&sdata->ckdb_msg_lock);
+
+	json_msg = json_dumps(val, JSON_COMPACT);
 	if (unlikely(!json_msg))
 		goto out;
 	ASPRINTF(&ret, "%s.id.json=%s", ckdb_ids[idtype], json_msg);
@@ -655,7 +665,7 @@ static void _ckdbq_add(ckpool_t *ckp, const int idtype, json_t *val, const char
 	if (CKP_STANDALONE(ckp))
 		return json_decref(val);
 
-	json_msg = ckdb_msg(ckp, val, idtype);
+	json_msg = ckdb_msg(ckp, sdata, val, idtype);
 	if (unlikely(!json_msg)) {
 		LOGWARNING("Failed to dump json from %s %s:%d", file, func, line);
 		return;
@@ -2349,9 +2359,9 @@ static int send_recv_auth(stratum_instance_t *client)
 	json_set_string(val, "createcode", __func__);
 	json_set_string(val, "createinet", client->address);
 	if (user->btcaddress)
-		json_msg = ckdb_msg(ckp, val, ID_ADDRAUTH);
+		json_msg = ckdb_msg(ckp, sdata, val, ID_ADDRAUTH);
 	else
-		json_msg = ckdb_msg(ckp, val, ID_AUTH);
+		json_msg = ckdb_msg(ckp, sdata, val, ID_AUTH);
 	if (unlikely(!json_msg)) {
 		LOGWARNING("Failed to dump json in send_recv_auth");
 		goto out;
@@ -4467,6 +4477,7 @@ int stratifier(proc_instance_t *pi)
 	cklock_init(&sdata->instance_lock);
 
 	mutex_init(&sdata->ckdb_lock);
+	mutex_init(&sdata->ckdb_msg_lock);
 	sdata->ssends = create_ckmsgq(ckp, "ssender", &ssend_process);
 	/* Create half as many share processing threads as there are CPUs */
 	threads = sysconf(_SC_NPROCESSORS_ONLN) / 2 ? : 1;