diff --git a/contrib/plugins/cowsay.sh b/contrib/plugins/cowsay.sh
index c99542039..8d8a40dd4 100755
--- a/contrib/plugins/cowsay.sh
+++ b/contrib/plugins/cowsay.sh
@@ -17,14 +17,14 @@ EOF
 # Eg. {"jsonrpc":"2.0","id":2,"method":"getmanifest","params":{}}\n\n
 read -r JSON
 read -r _
-id=$(echo "$JSON" | sed 's/.*"id" *: *\([0-9]*\),.*/\1/')
+id=$(echo "$JSON" | sed 's/.*"id" *: *\([^,]*\),.*/\1/')
 
 echo '{"jsonrpc":"2.0","id":'"$id"',"result":{"dynamic":true,"options":[],"rpcmethods":[{"name":"cowsay","usage":"<string>","description":"Have a cow, man!"}]}}'
 
 # Eg. {"jsonrpc":"2.0","id":5,"method":"init","params":{"options":{},"configuration":{"lightning-dir":"/home/rusty/.lightning","rpc-file":"lightning-rpc","startup":false}}}\n\n
 read -r JSON
 read -r _
-id=$(echo "$JSON" | sed 's/.*"id" *: *\([0-9]*\),.*/\1/')
+id=$(echo "$JSON" | sed 's/.*"id" *: *\([^,]*\),.*/\1/')
 
 echo '{"jsonrpc":"2.0","id":'"$id"',"result":{}}'
 
diff --git a/lightningd/jsonrpc.c b/lightningd/jsonrpc.c
index 765401640..621e3147e 100644
--- a/lightningd/jsonrpc.c
+++ b/lightningd/jsonrpc.c
@@ -1324,7 +1324,8 @@ struct jsonrpc_request *jsonrpc_request_start_(
 {
 	struct jsonrpc_request *r = tal(ctx, struct jsonrpc_request);
 	static u64 next_request_id = 0;
-	r->id = next_request_id++;
+	r->id = tal_fmt(r, "cln:%s#%"PRIu64, method, next_request_id);
+	next_request_id++;
 	r->notify_cb = notify_cb;
 	r->response_cb = response_cb;
 	r->response_cb_arg = response_cb_arg;
@@ -1337,12 +1338,12 @@ struct jsonrpc_request *jsonrpc_request_start_(
 	if (add_header) {
 		json_object_start(r->stream, NULL);
 		json_add_string(r->stream, "jsonrpc", "2.0");
-		json_add_u64(r->stream, "id", r->id);
+		json_add_string(r->stream, "id", r->id);
 		json_add_string(r->stream, "method", method);
 		json_object_start(r->stream, "params");
 	}
 	if (log)
-		log_debug(log, "OUT:id=%"PRIu64, r->id);
+		log_debug(log, "OUT:id=%s", r->id);
 
 	return r;
 }
diff --git a/lightningd/jsonrpc.h b/lightningd/jsonrpc.h
index 6339e4c12..659f65e3c 100644
--- a/lightningd/jsonrpc.h
+++ b/lightningd/jsonrpc.h
@@ -68,7 +68,7 @@ struct jsonrpc_notification {
 };
 
 struct jsonrpc_request {
-	u64 id;
+	const char *id;
 	const char *method;
 	struct json_stream *stream;
 	void (*notify_cb)(const char *buffer,
diff --git a/lightningd/plugin.c b/lightningd/plugin.c
index 25a8703ba..075b886e6 100644
--- a/lightningd/plugin.c
+++ b/lightningd/plugin.c
@@ -48,7 +48,7 @@ struct plugin_rpccall {
 static void memleak_help_pending_requests(struct htable *memtable,
 					  struct plugins *plugins)
 {
-	memleak_remove_uintmap(memtable, &plugins->pending_requests);
+	memleak_remove_strmap(memtable, &plugins->pending_requests);
 }
 #endif /* DEVELOPER */
 
@@ -86,7 +86,7 @@ struct plugins *plugins_new(const tal_t *ctx, struct log_book *log_book,
 #if DEVELOPER
 	p->dev_builtin_plugins_unimportant = false;
 #endif /* DEVELOPER */
-	uintmap_init(&p->pending_requests);
+	strmap_init(&p->pending_requests);
 	memleak_add_helper(p, memleak_help_pending_requests);
 
 	return p;
@@ -435,17 +435,18 @@ static const char *plugin_notify_handle(struct plugin *plugin,
 					const jsmntok_t *paramstok)
 {
 	const jsmntok_t *idtok;
-	u64 id;
 	struct jsonrpc_request *request;
 
 	/* id inside params tells us which id to redirect to. */
 	idtok = json_get_member(plugin->buffer, paramstok, "id");
-	if (!idtok || !json_to_u64(plugin->buffer, idtok, &id)) {
+	if (!idtok) {
 		return tal_fmt(plugin,
-			       "JSON-RPC notify \"id\"-field is not a u64");
+			       "JSON-RPC notify \"id\"-field is not present");
 	}
 
-	request = uintmap_get(&plugin->plugins->pending_requests, id);
+	request = strmap_getn(&plugin->plugins->pending_requests,
+			      plugin->buffer + idtok->start,
+			      idtok->end - idtok->start);
 	if (!request) {
 		return tal_fmt(
 			plugin,
@@ -565,16 +566,10 @@ static const char *plugin_response_handle(struct plugin *plugin,
 {
 	struct plugin_destroyed *pd;
 	struct jsonrpc_request *request;
-	u64 id;
-	/* We only send u64 ids, so if this fails it's a critical error (note
-	 * that this also works if id is inside a JSON string!). */
-	if (!json_to_u64(plugin->buffer, idtok, &id)) {
-		return tal_fmt(plugin,
-			       "JSON-RPC response \"id\"-field is not a u64");
-	}
-
-	request = uintmap_get(&plugin->plugins->pending_requests, id);
 
+	request = strmap_getn(&plugin->plugins->pending_requests,
+			      plugin->buffer + idtok->start,
+			      idtok->end - idtok->start);
 	if (!request) {
 		return tal_fmt(
 			plugin,
@@ -1029,18 +1024,31 @@ static void json_stream_forward_change_id(struct json_stream *stream,
 					  const char *buffer,
 					  const jsmntok_t *toks,
 					  const jsmntok_t *idtok,
-					  const char *new_id)
+					  const char *new_id,
+					  bool add_quotes)
 {
 	/* We copy everything, but replace the id. Special care has to
 	 * be taken when the id that is being replaced is a string. If
 	 * we don't crop the quotes off we'll transform a numeric
 	 * new_id into a string, or even worse, quote a string id
 	 * twice. */
-	size_t offset = idtok->type==JSMN_STRING?1:0;
+	size_t offset = 0;
+
+	if (idtok->type == JSMN_STRING) {
+		if (add_quotes)
+			add_quotes = false;
+		else
+			offset = 1;
+	}
+
 	json_stream_append(stream, buffer + toks->start,
 			   idtok->start - toks->start - offset);
 
+	if (add_quotes)
+		json_stream_append(stream, "\"", 1);
 	json_stream_append(stream, new_id, strlen(new_id));
+	if (add_quotes)
+		json_stream_append(stream, "\"", 1);
 	json_stream_append(stream, buffer + idtok->end + offset,
 			   toks->end - idtok->end - offset);
 }
@@ -1054,7 +1062,8 @@ static void plugin_rpcmethod_cb(const char *buffer,
 	struct json_stream *response;
 
 	response = json_stream_raw_for_cmd(cmd);
-	json_stream_forward_change_id(response, buffer, toks, idtok, cmd->id);
+	json_stream_forward_change_id(response, buffer, toks, idtok, cmd->id,
+				      false);
 	json_stream_double_cr(response);
 	command_raw_complete(cmd, response);
 
@@ -1080,7 +1089,7 @@ static void plugin_notify_cb(const char *buffer,
 	json_add_tok(response, "method", methodtok, buffer);
 	json_stream_append(response, ",\"params\":", strlen(",\"params\":"));
 	json_stream_forward_change_id(response, buffer,
-				      paramtoks, idtok, cmd->id);
+				      paramtoks, idtok, cmd->id, false);
 	json_object_end(response);
 
 	json_stream_double_cr(response);
@@ -1112,7 +1121,6 @@ static struct command_result *plugin_rpcmethod_dispatch(struct command *cmd,
 	const jsmntok_t *idtok;
 	struct plugin *plugin;
 	struct jsonrpc_request *req;
-	char id[STR_MAX_CHARS(u64)];
 	struct plugin_rpccall *call;
 
 	if (cmd->mode == CMD_CHECK)
@@ -1136,9 +1144,8 @@ static struct command_result *plugin_rpcmethod_dispatch(struct command *cmd,
 	call->plugin = plugin;
 	list_add_tail(&plugin->pending_rpccalls, &call->list);
 
-	snprintf(id, ARRAY_SIZE(id), "%"PRIu64, req->id);
-
-	json_stream_forward_change_id(req->stream, buffer, toks, idtok, id);
+	json_stream_forward_change_id(req->stream, buffer, toks, idtok, req->id,
+				      true);
 	json_stream_double_cr(req->stream);
 	plugin_request_send(plugin, req);
 	req->stream = NULL;
@@ -2048,7 +2055,7 @@ void plugins_notify(struct plugins *plugins,
 static void destroy_request(struct jsonrpc_request *req,
                             struct plugin *plugin)
 {
-	uintmap_del(&plugin->plugins->pending_requests, req->id);
+	strmap_del(&plugin->plugins->pending_requests, req->id, NULL);
 }
 
 void plugin_request_send(struct plugin *plugin,
@@ -2056,7 +2063,7 @@ void plugin_request_send(struct plugin *plugin,
 {
 	/* Add to map so we can find it later when routing the response */
 	tal_steal(plugin, req);
-	uintmap_add(&plugin->plugins->pending_requests, req->id, req);
+	strmap_add(&plugin->plugins->pending_requests, req->id, req);
 	/* Add destructor in case plugin dies. */
 	tal_add_destructor2(req, destroy_request, plugin);
 	plugin_send(plugin, req->stream);
diff --git a/lightningd/plugin.h b/lightningd/plugin.h
index 14b13ff54..4b33b736e 100644
--- a/lightningd/plugin.h
+++ b/lightningd/plugin.h
@@ -100,7 +100,7 @@ struct plugins {
 	bool startup;
 
 	/* Currently pending requests by their request ID */
-	UINTMAP(struct jsonrpc_request *) pending_requests;
+	STRMAP(struct jsonrpc_request *) pending_requests;
 	struct log *log;
 	struct log_book *log_book;
 
diff --git a/tests/test_invoices.py b/tests/test_invoices.py
index 84315bc42..743caf9bd 100644
--- a/tests/test_invoices.py
+++ b/tests/test_invoices.py
@@ -16,6 +16,10 @@ def test_invoice(node_factory, chainparams):
     addr2 = l2.rpc.newaddr('p2sh-segwit')['p2sh-segwit']
     before = int(time.time())
     inv = l1.rpc.invoice(123000, 'label', 'description', 3700, [addr1, addr2])
+
+    # Side note: invoice calls out to listincoming, so check JSON id is as expected
+    l1.daemon.wait_for_log(": OUT:id=cln:listincoming#[0-9]*")
+
     after = int(time.time())
     b11 = l1.rpc.decodepay(inv['bolt11'])
     assert b11['currency'] == chainparams['bip173_prefix']