diff --git a/lightningd/dev_ping.c b/lightningd/dev_ping.c
index c66229a77..bb8896781 100644
--- a/lightningd/dev_ping.c
+++ b/lightningd/dev_ping.c
@@ -96,6 +96,7 @@ static void json_dev_ping(struct command *cmd,
 	}
 
 	subd_req(owner, owner, take(msg), -1, 0, ping_reply, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command dev_ping_command = {
diff --git a/lightningd/gossip_control.c b/lightningd/gossip_control.c
index 792d4a47c..eaa9ea912 100644
--- a/lightningd/gossip_control.c
+++ b/lightningd/gossip_control.c
@@ -174,6 +174,7 @@ static void json_getnodes(struct command *cmd, const char *buffer,
 {
 	u8 *req = towire_gossip_getnodes_request(cmd);
 	subd_req(cmd, cmd->ld->gossip, req, -1, 0, json_getnodes_reply, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command getnodes_command = {
@@ -256,6 +257,7 @@ static void json_getroute(struct command *cmd, const char *buffer, const jsmntok
 	}
 	u8 *req = towire_gossip_getroute_request(cmd, &ld->id, &id, msatoshi, riskfactor*1000, cltv);
 	subd_req(ld->gossip, ld->gossip, req, -1, 0, json_getroute_reply, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command getroute_command = {
@@ -315,6 +317,7 @@ static void json_getchannels(struct command *cmd, const char *buffer,
 	u8 *req = towire_gossip_getchannels_request(cmd);
 	subd_req(cmd->ld->gossip, cmd->ld->gossip,
 		 req, -1, 0, json_getchannels_reply, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command getchannels_command = {
diff --git a/lightningd/invoice.c b/lightningd/invoice.c
index b31943566..55703d13e 100644
--- a/lightningd/invoice.c
+++ b/lightningd/invoice.c
@@ -394,6 +394,7 @@ static void json_waitanyinvoice(struct command *cmd,
 	w = tal(cmd, struct invoice_waiter);
 	w->cmd = cmd;
 	list_add_tail(&invs->invoice_waiters, &w->list);
+	command_still_pending(cmd);
 }
 
 static const struct json_command waitanyinvoice_command = {
@@ -439,6 +440,7 @@ static void json_waitinvoice(struct command *cmd,
 		w = tal(cmd, struct invoice_waiter);
 		w->cmd = cmd;
 		list_add_tail(&invs->invoice_waiters, &w->list);
+		command_still_pending(cmd);
 	}
 }
 
diff --git a/lightningd/jsonrpc.c b/lightningd/jsonrpc.c
index 5075dcc90..d6043bcfa 100644
--- a/lightningd/jsonrpc.c
+++ b/lightningd/jsonrpc.c
@@ -438,6 +438,11 @@ void command_fail(struct command *cmd, const char *fmt, ...)
 	jcon->current = tal_free(cmd);
 }
 
+void command_still_pending(struct command *cmd)
+{
+	cmd->pending = true;
+}
+
 static void json_command_malformed(struct json_connection *jcon,
 				   const char *id,
 				   const char *error)
@@ -476,6 +481,7 @@ static void parse_request(struct json_connection *jcon, const jsmntok_t tok[])
 	jcon->current = tal(jcon->ld, struct command);
 	jcon->current->jcon = jcon;
 	jcon->current->ld = jcon->ld;
+	jcon->current->pending = false;
 	jcon->current->id = tal_strndup(jcon->current,
 					json_tok_contents(jcon->buffer, id),
 					json_tok_len(id));
@@ -509,6 +515,10 @@ static void parse_request(struct json_connection *jcon, const jsmntok_t tok[])
 	db_begin_transaction(jcon->ld->wallet->db);
 	cmd->dispatch(jcon->current, jcon->buffer, params);
 	db_commit_transaction(jcon->ld->wallet->db);
+
+	/* If they didn't complete it, they must call command_still_pending */
+	if (jcon->current)
+		assert(jcon->current->pending);
 }
 
 static struct io_plan *write_json(struct io_conn *conn,
diff --git a/lightningd/jsonrpc.h b/lightningd/jsonrpc.h
index 3627a397f..9989f5dbd 100644
--- a/lightningd/jsonrpc.h
+++ b/lightningd/jsonrpc.h
@@ -16,6 +16,8 @@ struct command {
 	const char *id;
 	/* The connection, or NULL if it closed. */
 	struct json_connection *jcon;
+	/* Have we been marked by command_still_pending?  For debugging... */
+	bool pending;
 };
 
 struct json_connection {
@@ -56,6 +58,9 @@ struct json_result *null_response(const tal_t *ctx);
 void command_success(struct command *cmd, struct json_result *response);
 void PRINTF_FMT(2, 3) command_fail(struct command *cmd, const char *fmt, ...);
 
+/* Mainly for documentation, that we plan to close this later. */
+void command_still_pending(struct command *cmd);
+
 /* '"fieldname" : "0289abcdef..."' or "0289abcdef..." if fieldname is NULL */
 void json_add_pubkey(struct json_result *response,
 		     const char *fieldname,
diff --git a/lightningd/pay.c b/lightningd/pay.c
index 851f259ba..94da4e7eb 100644
--- a/lightningd/pay.c
+++ b/lightningd/pay.c
@@ -144,7 +144,8 @@ static void pay_command_destroyed(struct pay_command *pc)
 	list_del(&pc->list);
 }
 
-static void send_payment(struct command *cmd,
+/* Returns true if it's still pending. */
+static bool send_payment(struct command *cmd,
 			 const struct sha256 *rhash,
 			 const struct route_hop *route)
 {
@@ -189,7 +190,7 @@ static void send_payment(struct command *cmd,
 		if (pc->out) {
 			log_add(cmd->ld->log, "... still in progress");
 			command_fail(cmd, "still in progress");
-			return;
+			return false;
 		}
 		if (pc->rval) {
 			size_t old_nhops = tal_count(pc->ids);
@@ -199,7 +200,7 @@ static void send_payment(struct command *cmd,
 				command_fail(cmd,
 					     "already succeeded with amount %"
 					     PRIu64, pc->msatoshi);
-				return;
+				return false;
 			}
 			if (!structeq(&pc->ids[old_nhops-1], &ids[n_hops-1])) {
 				char *previd;
@@ -208,10 +209,10 @@ static void send_payment(struct command *cmd,
 				command_fail(cmd,
 					     "already succeeded to %s",
 					     previd);
-				return;
+				return false;
 			}
 			json_pay_success(cmd, pc->rval);
-			return;
+			return false;
 		}
 		/* FIXME: We can free failed ones... */
 		log_add(cmd->ld->log, "... retrying");
@@ -220,7 +221,7 @@ static void send_payment(struct command *cmd,
 	peer = peer_by_id(cmd->ld, &ids[0]);
 	if (!peer) {
 		command_fail(cmd, "no connection to first peer found");
-		return;
+		return false;
 	}
 
 	randombytes_buf(&sessionkey, sizeof(sessionkey));
@@ -272,8 +273,9 @@ static void send_payment(struct command *cmd,
 	if (failcode) {
 		command_fail(cmd, "first peer not ready: %s",
 			     onion_type_name(failcode));
-		return;
+		return false;
 	}
+	return true;
 }
 
 static void json_sendpay(struct command *cmd,
@@ -364,7 +366,8 @@ static void json_sendpay(struct command *cmd,
 		return;
 	}
 
-	send_payment(cmd, &rhash, route);
+	if (send_payment(cmd, &rhash, route))
+		command_still_pending(cmd);
 }
 
 static const struct json_command sendpay_command = {
@@ -468,6 +471,7 @@ static void json_pay(struct command *cmd,
 					     msatoshi, riskfactor*1000,
 					     b11->min_final_cltv_expiry);
 	subd_req(pay, cmd->ld->gossip, req, -1, 0, json_pay_getroute_reply, pay);
+	command_still_pending(cmd);
 }
 
 static const struct json_command pay_command = {
diff --git a/lightningd/peer_control.c b/lightningd/peer_control.c
index 992c5aa91..bfe466ee8 100644
--- a/lightningd/peer_control.c
+++ b/lightningd/peer_control.c
@@ -823,6 +823,7 @@ static void json_connect(struct command *cmd,
 
 	/* Leave this here for gossip_peer_connected */
 	new_connect(cmd->ld, &id, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command connect_command = {
@@ -966,6 +967,7 @@ static void json_getpeers(struct command *cmd,
 	subd_req(cmd, cmd->ld->gossip,
 		 take(towire_gossip_getpeers_request(cmd)),
 		 -1, 0, gossipd_getpeers_complete, gpa);
+	command_still_pending(cmd);
 }
 
 static const struct json_command getpeers_command = {
@@ -2616,6 +2618,7 @@ static void json_fund_channel(struct command *cmd,
 
 	msg = towire_gossipctl_release_peer(cmd, &fc->peerid);
 	subd_req(fc, cmd->ld->gossip, msg, -1, 2, gossip_peer_released, fc);
+	command_still_pending(cmd);
 }
 
 static const struct json_command fund_channel_command = {
@@ -2818,6 +2821,7 @@ static void json_dev_reenable_commit(struct command *cmd,
 	msg = towire_channel_dev_reenable_commit(peer);
 	subd_req(peer, peer->owner, take(msg), -1, 0,
 		 dev_reenable_commit_finished, cmd);
+	command_still_pending(cmd);
 }
 
 static const struct json_command dev_reenable_commit = {
diff --git a/wallet/walletrpc.c b/wallet/walletrpc.c
index 7afa4782f..1b86b8d3a 100644
--- a/wallet/walletrpc.c
+++ b/wallet/walletrpc.c
@@ -326,6 +326,7 @@ static void json_withdraw(struct command *cmd,
 	withdraw->hextx = tal_hex(withdraw, linearize_tx(cmd, tx));
 	bitcoind_sendrawtx(cmd->ld->topology->bitcoind, withdraw->hextx,
 			   wallet_withdrawal_broadcast, withdraw);
+	command_still_pending(cmd);
 }
 
 static const struct json_command withdraw_command = {