diff --git a/devtools/Makefile b/devtools/Makefile
index 8018804b8..73353619c 100644
--- a/devtools/Makefile
+++ b/devtools/Makefile
@@ -1,6 +1,6 @@
 DEVTOOLS_SRC := devtools/gen_print_wire.c devtools/gen_print_onion_wire.c devtools/print_wire.c
 DEVTOOLS_OBJS := $(DEVTOOLS_SRC:.c=.o)
-DEVTOOLS := devtools/bolt11-cli devtools/decodemsg devtools/onion devtools/dump-gossipstore devtools/gossipwith
+DEVTOOLS := devtools/bolt11-cli devtools/decodemsg devtools/onion devtools/dump-gossipstore devtools/gossipwith devtools/create-gossipstore
 DEVTOOLS_TOOL_SRC := $(DEVTOOLS:=.c)
 DEVTOOLS_TOOL_OBJS := $(DEVTOOLS_TOOL_SRC:.c=.o)
 
@@ -16,7 +16,8 @@ DEVTOOLS_COMMON_OBJS :=				\
 	common/utils.o				\
 	common/version.o			\
 	common/wireaddr.o			\
-	wire/gen_onion_wire.o
+	wire/gen_onion_wire.o			\
+	wire/gen_peer_wire.o
 
 devtools-all: $(DEVTOOLS)
 
@@ -39,6 +40,10 @@ devtools/decodemsg: $(DEVTOOLS_OBJS) $(DEVTOOLS_COMMON_OBJS) $(JSMN_OBJS) $(CCAN
 devtools/dump-gossipstore: $(DEVTOOLS_OBJS) $(DEVTOOLS_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS) $(BITCOIN_OBJS) wire/fromwire.o wire/towire.o devtools/dump-gossipstore.o gossipd/gen_gossip_store.o
 
 devtools/dump-gossipstore.o: gossipd/gen_gossip_store.h
+
+devtools/create-gossipstore: $(DEVTOOLS_OBJS) $(DEVTOOLS_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS) $(BITCOIN_OBJS) wire/fromwire.o wire/towire.o devtools/create-gossipstore.o gossipd/gen_gossip_store.o
+devtools/create-gossipstore.o: gossipd/gen_gossip_store.h
+
 devtools/onion.c: ccan/config.h
 
 devtools/onion: $(DEVTOOLS_OBJS) $(DEVTOOLS_COMMON_OBJS) $(JSMN_OBJS) $(CCAN_OBJS) $(BITCOIN_OBJS) wire/fromwire.o wire/towire.o devtools/onion.o common/sphinx.o
diff --git a/devtools/create-gossipstore.c b/devtools/create-gossipstore.c
new file mode 100644
index 000000000..87337e932
--- /dev/null
+++ b/devtools/create-gossipstore.c
@@ -0,0 +1,103 @@
+#include <ccan/crc/crc.h>
+#include <ccan/err/err.h>
+#include <ccan/opt/opt.h>
+#include <ccan/read_write_all/read_write_all.h>
+#include <common/type_to_string.h>
+#include <common/utils.h>
+#include <fcntl.h>
+#include <gossipd/gen_gossip_store.h>
+#include <gossipd/gossip_store.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <wire/gen_peer_wire.h>
+
+int main(int argc, char *argv[])
+{
+	u8 version;
+	beint16_t be_inlen;
+	struct amount_sat sat;
+	bool verbose = false;
+	char *infile = NULL, *outfile = NULL;
+	int infd, outfd;
+
+	setup_locale();
+
+	opt_register_noarg("--verbose|-v", opt_set_bool, &verbose,
+			   "Print progress to stderr");
+	opt_register_arg("--output|-o", opt_set_charp, NULL, &outfile,
+			 "Send output to this file instead of stdout");
+	opt_register_arg("--input|-i", opt_set_charp, NULL, &infile,
+			 "Read input from this file instead of stdin");
+	opt_register_noarg("--help|-h", opt_usage_and_exit,
+			   "default-satoshis\n"
+			   "Create gossip store, from be16 / input messages",
+			   "Print this message.");
+
+	opt_parse(&argc, argv, opt_log_stderr_exit);
+	if (argc != 2)
+		errx(1, "Need default-satoshi argument for channel amounts");
+	if (!parse_amount_sat(&sat, argv[1], strlen(argv[1])))
+		errx(1, "Invalid satoshi amount %s", argv[1]);
+
+	if (infile) {
+		infd = open(infile, O_RDONLY);
+		if (infd < 0)
+			err(1, "opening %s", infile);
+	} else
+		infd = STDIN_FILENO;
+
+	if (outfile) {
+		outfd = open(outfile, O_WRONLY|O_TRUNC|O_CREAT, 0666);
+		if (outfd < 0)
+			err(1, "opening %s", outfile);
+	} else
+		outfd = STDOUT_FILENO;
+
+	version = GOSSIP_STORE_VERSION;
+	if (!write_all(outfd, &version, sizeof(version)))
+		err(1, "Writing version");
+
+	while (read_all(infd, &be_inlen, sizeof(be_inlen))) {
+		u32 msglen = be16_to_cpu(be_inlen);
+		u8 *inmsg = tal_arr(NULL, u8, msglen), *outmsg;
+		beint32_t be_outlen;
+		beint32_t becsum;
+
+		if (!read_all(infd, inmsg, msglen))
+			err(1, "Only read partial message");
+
+		switch (fromwire_peektype(inmsg)) {
+		case WIRE_CHANNEL_ANNOUNCEMENT:
+			outmsg = towire_gossip_store_channel_announcement(inmsg, inmsg, sat);
+			break;
+		case WIRE_CHANNEL_UPDATE:
+			outmsg = towire_gossip_store_channel_update(inmsg, inmsg);
+			break;
+		case WIRE_NODE_ANNOUNCEMENT:
+			outmsg = towire_gossip_store_node_announcement(inmsg, inmsg);
+			break;
+		default:
+			warnx("Unknown message %u (%s)", fromwire_peektype(inmsg),
+			      wire_type_name(fromwire_peektype(inmsg)));
+			tal_free(inmsg);
+			continue;
+		}
+		if (verbose)
+			fprintf(stderr, "%s->%s\n",
+				wire_type_name(fromwire_peektype(inmsg)),
+				gossip_store_type_name(fromwire_peektype(outmsg)));
+
+		becsum = cpu_to_be32(crc32c(0, outmsg, tal_count(outmsg)));
+		be_outlen = cpu_to_be32(tal_count(outmsg));
+		if (!write_all(outfd, &be_outlen, sizeof(be_outlen))
+		    || !write_all(outfd, &becsum, sizeof(becsum))
+		    || !write_all(outfd, outmsg, tal_count(outmsg))) {
+			exit(1);
+		}
+		tal_free(inmsg);
+	}
+	return 0;
+}