diff --git a/common/configdir.c b/common/configdir.c
index 8f8a30eec..c6ac3fdcf 100644
--- a/common/configdir.c
+++ b/common/configdir.c
@@ -179,7 +179,8 @@ void setup_option_allocators(void)
 
 static void parse_configvars(struct configvar **cvs,
 			     bool early,
-			     bool full_knowledge)
+			     bool full_knowledge,
+			     bool developer)
 {
 	for (size_t i = 0; i < tal_count(cvs); i++) {
 		const char *problem;
@@ -194,7 +195,7 @@ static void parse_configvars(struct configvar **cvs,
 		problem = configvar_parse(cvs[i],
 					  early,
 					  should_know,
-					  IFDEV(true, false));
+					  developer);
 		current_cv = NULL;
 		if (!problem)
 			continue;
@@ -354,7 +355,7 @@ struct configvar **initial_config_opts(const tal_t *ctx,
 			       "Set JSON-RPC socket (or /dev/tty)");
 
 	cmdline_cvs = gather_cmdline_args(tmpctx, argc, argv, remove_args);
-	parse_configvars(cmdline_cvs, true, false);
+	parse_configvars(cmdline_cvs, true, false, false);
 
 	/* Base default or direct config can set network */
 	if (*config_filename) {
@@ -371,7 +372,7 @@ struct configvar **initial_config_opts(const tal_t *ctx,
 						  false, 0);
 		/* This might set network! */
 		parse_configvars(configvar_join(tmpctx, base_cvs, cmdline_cvs),
-				 true, false);
+				 true, false, false);
 
 		/* Now, we can get network config */
 		dir = path_join(tmpctx, dir, chainparams->network_name);
@@ -385,7 +386,7 @@ struct configvar **initial_config_opts(const tal_t *ctx,
 
 	/* This will be called again, once caller has added their own
 	 * early vars! */
-	parse_configvars_early(cvs);
+	parse_configvars_early(cvs, false);
 
 	*config_netdir
 		= path_join(NULL, *config_basedir, chainparams->network_name);
@@ -395,15 +396,16 @@ struct configvar **initial_config_opts(const tal_t *ctx,
 	return cvs;
 }
 
-void parse_configvars_early(struct configvar **cvs)
+void parse_configvars_early(struct configvar **cvs, bool developer)
 {
-	parse_configvars(cvs, true, false);
+	parse_configvars(cvs, true, false, developer);
 }
 
 void parse_configvars_final(struct configvar **cvs,
-			    bool full_knowledge)
+			    bool full_knowledge,
+			    bool developer)
 {
-	parse_configvars(cvs, false, full_knowledge);
+	parse_configvars(cvs, false, full_knowledge, developer);
 	configvar_finalize_overrides(cvs);
 }
 
diff --git a/common/configdir.h b/common/configdir.h
index e25207be5..68e06ca27 100644
--- a/common/configdir.h
+++ b/common/configdir.h
@@ -30,12 +30,12 @@ struct configvar **initial_config_opts(const tal_t *ctx,
 				       char **rpc_filename);
 
 /* This is called before we know all the options. */
-void parse_configvars_early(struct configvar **cvs);
+void parse_configvars_early(struct configvar **cvs, bool developer);
 
 /* This is called once, after we know all the options (if full_knowledge
  * is false, ignore unknown non-cmdline options). */
 void parse_configvars_final(struct configvar **cvs,
-			    bool full_knowledge);
+			    bool full_knowledge, bool developer);
 
 /* For listconfigs to detect. */
 bool is_restricted_ignored(const void *fn);
diff --git a/doc/lightning-listconfigs.7.md b/doc/lightning-listconfigs.7.md
index 79c0d2d59..667198b7c 100644
--- a/doc/lightning-listconfigs.7.md
+++ b/doc/lightning-listconfigs.7.md
@@ -54,6 +54,9 @@ On success, an object is returned, containing:
   - **conf** (object, optional):
     - **value\_str** (string): field from cmdline
     - **source** (string): source of configuration setting (always "cmdline")
+  - **developer** (object, optional) *(added v23.08)*:
+    - **set** (boolean): `true` if set in config or cmdline
+    - **source** (string): source of configuration setting
   - **clear-plugins** (object, optional):
     - **set** (boolean): `true` if set in config or cmdline
     - **source** (string): source of configuration setting
@@ -352,6 +355,7 @@ On success, an object is returned, containing:
 - **dev-allowdustreserve** (boolean, optional): Whether we allow setting dust reserves **deprecated, removal in v24.05**
 - **announce-addr-dns** (boolean, optional): Whether we put DNS entries into node\_announcement **deprecated, removal in v24.05** *(added v22.11.1)*
 - **require-confirmed-inputs** (boolean, optional): Request peers to only send confirmed inputs (dual-fund only) **deprecated, removal in v24.05**
+- **developer** (boolean, optional): Whether developer mode is enabled *(added v23.08)*
 - **commit-fee** (u64, optional): The percentage of the 6-block fee estimate to use for commitment transactions **deprecated, removal in v24.05** *(added v23.05)*
 - **min-emergency-msat** (msat, optional): field from config or cmdline, or default *(added v23.08)*
 
@@ -471,4 +475,4 @@ RESOURCES
 
 Main web site: <https://github.com/ElementsProject/lightning>
 
-[comment]: # ( SHA256STAMP:8e7ec36b820cb17ecfc3066802bb07e159fffdd8dfe049d092b8f3b804e05588)
+[comment]: # ( SHA256STAMP:2ff237b19ffed3d97eabf67ff256df66d8c5063ad5086bb6a3d77e64f53f64db)
diff --git a/doc/lightningd-config.5.md b/doc/lightningd-config.5.md
index 17689262f..0a91c2bb2 100644
--- a/doc/lightningd-config.5.md
+++ b/doc/lightningd-config.5.md
@@ -45,10 +45,14 @@ OPTIONS
 
 ### General options
 
+* **developer**
+
+  This enables developer mode, allowing developer options and commands to be used.  It also disabled deprecated APIs; use `allow-deprecated-apis=true` to re-enable them.
+
 * **allow-deprecated-apis**=*BOOL*
 
   Enable deprecated options, JSONRPC commands, fields, etc. It defaults to
-*true*, but you should set it to *false* when testing to ensure that an
+*true* outside developer mode, but you should set it to *false* when testing to ensure that an
 upgrade won't break your configuration.
 
 * **help**
diff --git a/doc/schemas/listconfigs.schema.json b/doc/schemas/listconfigs.schema.json
index d2a639b5f..ece50df7a 100644
--- a/doc/schemas/listconfigs.schema.json
+++ b/doc/schemas/listconfigs.schema.json
@@ -32,6 +32,25 @@
             }
           }
         },
+        "developer": {
+          "type": "object",
+          "added": "v23.08",
+          "additionalProperties": false,
+          "required": [
+            "set",
+            "source"
+          ],
+          "properties": {
+            "set": {
+              "type": "boolean",
+              "description": "`true` if set in config or cmdline"
+            },
+            "source": {
+              "type": "string",
+              "description": "source of configuration setting"
+            }
+          }
+        },
         "clear-plugins": {
           "type": "object",
           "additionalProperties": false,
@@ -1731,6 +1750,11 @@
       "type": "boolean",
       "description": "Request peers to only send confirmed inputs (dual-fund only)"
     },
+    "developer": {
+      "added": "v23.08",
+      "type": "boolean",
+      "description": "Whether developer mode is enabled"
+    },
     "commit-fee": {
       "deprecated": "v23.08",
       "type": "u64",
diff --git a/lightningd/lightningd.c b/lightningd/lightningd.c
index 9e4f137d4..02c2e0bc5 100644
--- a/lightningd/lightningd.c
+++ b/lightningd/lightningd.c
@@ -116,6 +116,9 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	 * us to use const more liberally: the style rule here is that you
 	 * should use 'const' on pointers if you can. */
 
+	/* They can turn this on with --developer */
+	ld->developer = IFDEV(true, false);
+
 	/*~ Note that we generally EXPLICITLY #if-wrap DEVELOPER code.  This
 	 * is a nod to keeping it minimal and explicit: we need this code for
 	 * testing, but its existence means we're not actually testing the
diff --git a/lightningd/lightningd.h b/lightningd/lightningd.h
index 37830d029..82fd3e82f 100644
--- a/lightningd/lightningd.h
+++ b/lightningd/lightningd.h
@@ -128,6 +128,9 @@ struct lightningd {
 	 * transaction. */
 	struct jsonrpc *jsonrpc;
 
+	/* --developer? */
+	bool developer;
+
 	/* Configuration file name */
 	char *config_filename;
 	/* Configuration settings. */
diff --git a/lightningd/options.c b/lightningd/options.c
index a493f693c..c93b43df6 100644
--- a/lightningd/options.c
+++ b/lightningd/options.c
@@ -1717,6 +1717,11 @@ void handle_early_opts(struct lightningd *ld, int argc, char *argv[])
 		     list_features_and_exit,
 		     ld, "List the features configured, and exit immediately");
 
+	/*~ We need to know this super-early, as it controls other options */
+	clnopt_noarg("--developer", OPT_EARLY|OPT_SHOWBOOL,
+		     opt_set_bool, &ld->developer,
+		     "Enable developer commands/options, disable legacy APIs");
+
 	/*~ This does enough parsing to get us the base configuration options */
 	ld->configvars = initial_config_opts(ld, &argc, argv, true,
 					     &ld->config_filename,
@@ -1763,6 +1768,10 @@ void handle_early_opts(struct lightningd *ld, int argc, char *argv[])
 			      ld->config_netdir, strerror(errno));
 	}
 
+	/* --developer changes default for APIs */
+	if (ld->developer)
+		ld->deprecated_apis = false;
+
 	/*~ We move files from old locations on first upgrade. */
 	promote_missing_files(ld);
 
@@ -1772,7 +1781,7 @@ void handle_early_opts(struct lightningd *ld, int argc, char *argv[])
 
 	/* Now, first-pass of parsing.  But only handle the early
 	 * options (testnet, plugins etc), others may be added on-demand */
-	parse_configvars_early(ld->configvars);
+	parse_configvars_early(ld->configvars, ld->developer);
 
 	/* Finalize the logging subsystem now. */
 	logging_options_parsed(ld->log_book);
@@ -1782,7 +1791,7 @@ void handle_opts(struct lightningd *ld)
 {
 	/* Now we know all the options, finish parsing and finish
 	 * populating ld->configvars with cmdline. */
-	parse_configvars_final(ld->configvars, true);
+	parse_configvars_final(ld->configvars, true, ld->developer);
 
 	/* We keep a separate variable rather than overriding always_use_proxy,
 	 * so listconfigs shows the correct thing. */
diff --git a/tools/check-manpage.sh b/tools/check-manpage.sh
index d333fd1b8..e50be1e9c 100755
--- a/tools/check-manpage.sh
+++ b/tools/check-manpage.sh
@@ -13,7 +13,7 @@ get_cmd_opts()
     COLUMNS=1000 $1 --help | sed -n 's/^\(-.|\)\?\(--[^	]*\)\(  \|	\).*/\2/p' | while IFS=$'\n' read -r opt; do
 	case "$opt" in
 	    # We don't document dev options.
-	    --dev*)
+	    --dev-*)
 		;;
 	    --*=*|--*' <arg>'*)
 		echo "${opt%%[ =]*}=" | cut -c3-