diff --git a/common/json.c b/common/json.c
index 41d04ebb3..c89d8af00 100644
--- a/common/json.c
+++ b/common/json.c
@@ -143,6 +143,13 @@ bool json_tok_bool(const char *buffer, const jsmntok_t *tok, bool *b)
 	return false;
 }
 
+bool json_tok_tok(const char *buffer, const jsmntok_t * tok,
+		  const jsmntok_t **out)
+{
+	*out = tok;
+	return true;
+}
+
 const jsmntok_t *json_next(const jsmntok_t *tok)
 {
 	const jsmntok_t *t;
diff --git a/common/json.h b/common/json.h
index a808cde9c..0c1cb12f3 100644
--- a/common/json.h
+++ b/common/json.h
@@ -42,6 +42,13 @@ bool json_tok_bitcoin_amount(const char *buffer, const jsmntok_t *tok,
 /* Extract boolean this (must be a true or false) */
 bool json_tok_bool(const char *buffer, const jsmntok_t *tok, bool *b);
 
+/*
+ * Set the address of @out to @tok.  Used as a param_table callback by handlers that
+ * want to unmarshal @tok themselves.
+ */
+bool json_tok_tok(const char *buffer, const jsmntok_t * tok,
+		  const jsmntok_t **out);
+
 /* Is this the null primitive? */
 bool json_tok_is_null(const char *buffer, const jsmntok_t *tok);
 
diff --git a/lightningd/Makefile b/lightningd/Makefile
index 193c2d177..b43cd4e30 100644
--- a/lightningd/Makefile
+++ b/lightningd/Makefile
@@ -70,6 +70,7 @@ LIGHTNINGD_SRC :=				\
 	lightningd/onchain_control.c		\
 	lightningd/opening_control.c		\
 	lightningd/options.c			\
+	lightningd/params.c			\
 	lightningd/pay.c			\
 	lightningd/payalgo.c			\
 	lightningd/peer_control.c		\
diff --git a/lightningd/params.c b/lightningd/params.c
new file mode 100644
index 000000000..e6c600b80
--- /dev/null
+++ b/lightningd/params.c
@@ -0,0 +1,297 @@
+#include <ccan/tal/str/str.h>
+#include <common/utils.h>
+#include <lightningd/json.h>
+#include <lightningd/jsonrpc.h>
+#include <lightningd/jsonrpc_errors.h>
+#include <lightningd/lightningd.h>
+#include <lightningd/params.h>
+
+struct param {
+	char *name;
+	bool required;
+	bool is_set;
+	param_cb cb;
+	void *arg;
+};
+
+void *param_is_set(struct param *def)
+{
+	return def->is_set ? def->arg : NULL;
+}
+
+struct param *param_add_(bool required, char *name, param_cb cb, void *arg)
+{
+#if DEVELOPER
+	assert(name);
+	assert(cb);
+	assert(arg);
+#endif
+	struct param *last = tal(tmpctx, struct param);
+	last->is_set = false;
+	last->name = tal_strdup(last, name);
+	last->cb = cb;
+	last->arg = arg;
+	last->required = required;
+	return last;
+}
+
+struct fail_format {
+	void *cb;
+	const char *format;
+};
+
+static struct fail_format fail_formats[] = {
+	{json_tok_bool, "'%s' should be 'true' or 'false', not '%.*s'"},
+	{json_tok_double, "'%s' should be a double, not '%.*s'"},
+	{json_tok_u64, "'%s' should be an unsigned 64 bit integer, not '%.*s'"},
+	{json_tok_number, "'%s' should be an integer, not '%.*s'"},
+	{json_tok_wtx,
+	 "'%s' should be 'all' or a positive integer greater than "
+	 "545, not '%.*s'"},
+	{NULL, "'%s' of '%.*s' is invalid'"}
+};
+
+static const char *find_fail_format(param_cb cb)
+{
+	struct fail_format *fmt = fail_formats;
+	while (fmt->cb != NULL) {
+		if (fmt->cb == cb)
+			break;
+		fmt++;
+	}
+	return fmt->format;
+}
+
+static bool make_callback(struct command *cmd,
+			  struct param *def,
+			  const char *buffer, const jsmntok_t * tok)
+{
+	def->is_set = true;
+	if (!def->cb(buffer, tok, def->arg)) {
+		struct json_result *data = new_json_result(cmd);
+		const char *val = tal_fmt(cmd, "%.*s", tok->end - tok->start,
+					  buffer + tok->start);
+		json_object_start(data, NULL);
+		json_add_string(data, def->name, val);
+		json_object_end(data);
+		command_fail_detailed(cmd, JSONRPC2_INVALID_PARAMS, data,
+				      find_fail_format(def->cb), def->name,
+				      tok->end - tok->start,
+				      buffer + tok->start);
+		return false;
+	}
+	return true;
+}
+
+static struct param **post_check(struct command *cmd, struct param **params)
+{
+	struct param **first = params;
+	struct param **last = first + tal_count(params);
+
+	/* Make sure required params were provided. */
+	while (first != last && (*first)->required) {
+		if (!(*first)->is_set) {
+			command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				     "missing required parameter: '%s'",
+				     (*first)->name);
+			return NULL;
+		}
+		first++;
+	}
+
+	/* Set optional missing jsmntok_t args to NULL.  */
+	while (first != last) {
+		struct param *p = *first;
+		if (!p->is_set && (p->cb == (param_cb) json_tok_tok)) {
+			jsmntok_t **tok = p->arg;
+			*tok = NULL;
+		}
+		first++;
+	}
+	return params;
+}
+
+static struct param **parse_by_position(struct command *cmd,
+					struct param **params,
+					const char *buffer,
+					const jsmntok_t tokens[])
+{
+	const jsmntok_t *tok = tokens + 1;
+	const jsmntok_t *end = json_next(tokens);
+	struct param **first = params;
+	struct param **last = first + tal_count(params);
+
+	while (first != last && tok != end) {
+		if (!json_tok_is_null(buffer, tok))
+			if (!make_callback(cmd, *first, buffer, tok))
+				return NULL;
+		tok = json_next(tok);
+		first++;
+	}
+
+	/* check for unexpected trailing params */
+	if (tok != end) {
+		command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+			     "too many parameters:"
+			     " got %u, expected %zu",
+			     tokens->size, tal_count(params));
+		return NULL;
+	}
+
+	return post_check(cmd, params);
+}
+
+static struct param *find_param(struct param **params, const char *start,
+				size_t n)
+{
+	struct param **first = params;
+	struct param **last = first + tal_count(params);
+
+	while (first != last) {
+		if (strncmp((*first)->name, start, n) == 0)
+			if (strlen((*first)->name) == n)
+				return *first;
+		first++;
+	}
+	return NULL;
+}
+
+static struct param **parse_by_name(struct command *cmd,
+				    struct param **params,
+				    const char *buffer,
+				    const jsmntok_t tokens[])
+{
+	const jsmntok_t *first = tokens + 1;
+	const jsmntok_t *last = json_next(tokens);
+
+	while (first != last) {
+		struct param *p = find_param(params, buffer + first->start,
+					     first->end - first->start);
+		if (!p) {
+			command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				     "unknown parameter: '%.*s'",
+				     first->end - first->start,
+				     buffer + first->start);
+			return NULL;
+		}
+
+		if (p->is_set) {
+			command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				     "duplicate json names: '%s'", p->name);
+			return NULL;
+		}
+
+		if (!make_callback(cmd, p, buffer, first + 1))
+			return NULL;
+		first = json_next(first + 1);
+	}
+	return post_check(cmd, params);
+}
+
+#if DEVELOPER
+static int comp_by_name(const void *a, const void *b)
+{
+	const char *x = (*(const struct param **) a)->name;
+	const char *y = (*(const struct param **) b)->name;
+	return strcmp(x, y);
+}
+
+static int comp_by_arg(const void *a, const void *b)
+{
+	size_t x = (size_t) ((*(const struct param **) a)->arg);
+	size_t y = (size_t) ((*(const struct param **) b)->arg);
+	return x - y;
+}
+
+/* This comparator is a bit different, but works well.
+ * Return 0 if @a is optional and @b is required. Otherwise return 1.
+ */
+static int comp_req_order(const void *a, const void *b)
+{
+	bool x = (bool) ((*(const struct param **) a)->required);
+	bool y = (bool) ((*(const struct param **) b)->required);
+	if (!x && y)
+		return 0;
+	return 1;
+}
+
+/*
+ * Make sure 2 sequential items in @params are not equal (based on
+ * provided comparator).
+ */
+static void check_distinct(struct param **params,
+			   int (*compar) (const void *, const void *))
+{
+	struct param **first = params;
+	struct param **last = first + tal_count(params);
+	first++;
+	while (first != last) {
+		assert(compar(first - 1, first) != 0);
+		first++;
+	}
+}
+
+static void check_unique(struct param **copy,
+			 int (*compar) (const void *, const void *))
+{
+	qsort(copy, tal_count(copy), sizeof(struct param *), compar);
+	check_distinct(copy, compar);
+}
+
+/*
+ * Verify consistent internal state.
+ */
+static void check_params(struct param **params)
+{
+	if (tal_count(params) < 2)
+		return;
+
+	/* make sure there are no required params following optional */
+	check_distinct(params, comp_req_order);
+
+	/* duplicate so we can sort */
+	struct param **copy = tal_dup_arr(params, struct param *,
+					  params, tal_count(params), 0);
+
+	/* check for repeated names and args */
+	check_unique(copy, comp_by_name);
+	check_unique(copy, comp_by_arg);
+
+	tal_free(copy);
+}
+#endif
+
+static struct param **param_parse_arr(struct command *cmd,
+				      const char *buffer,
+				      const jsmntok_t tokens[],
+				      struct param **params)
+{
+#if DEVELOPER
+	check_params(params);
+#endif
+	if (tokens->type == JSMN_ARRAY)
+		return parse_by_position(cmd, params, buffer, tokens);
+	else if (tokens->type == JSMN_OBJECT)
+		return parse_by_name(cmd, params, buffer, tokens);
+
+	command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+		     "Expected array or object for params");
+	return NULL;
+}
+
+struct param **param_parse(struct command *cmd, const char *buffer,
+			   const jsmntok_t tokens[], ...)
+{
+	struct param *def;
+	struct param **params = tal_arr(cmd, struct param *, 0);
+	va_list ap;
+	va_start(ap, tokens);
+	while ((def = va_arg(ap, struct param *)) != NULL) {
+		tal_steal(params, def);
+		tal_resize(&params, tal_count(params) + 1);
+		params[tal_count(params) - 1] = def;
+	}
+	va_end(ap);
+
+	return param_parse_arr(cmd, buffer, tokens, params);
+}
diff --git a/lightningd/params.h b/lightningd/params.h
new file mode 100644
index 000000000..1aab8ddc1
--- /dev/null
+++ b/lightningd/params.h
@@ -0,0 +1,93 @@
+#ifndef LIGHTNING_LIGHTNINGD_PARAMS_H
+#define LIGHTNING_LIGHTNINGD_PARAMS_H
+#include "config.h"
+#include <ccan/ccan/typesafe_cb/typesafe_cb.h>
+
+struct param;
+
+/*
+  Typesafe callback system for unmarshalling and validating json parameters.
+
+  Typical usage:
+	unsigned cltv;
+	const jsmntok_t *note;
+	u64 msatoshi;
+	struct param * mp;
+
+	if (!param_parse(cmd, buffer, tokens,
+			 param_req("cltv", json_tok_number, &cltv),
+			 param_opt("note", json_tok_tok, &note),
+			 mp = param_opt("msatoshi", json_tok_u64, &msatoshi),
+			 NULL))
+		return;
+
+  At this point in the code you can be assured the json tokens were successfully
+  parsed.  If not, param_parse() returned NULL, having already called
+  command_fail() with a descriptive error message. The data section of the json
+  result contains the offending parameter and its value.
+
+  cltv is a required parameter, and is set correctly.
+
+  note and msatoshi are optional parameters.  You can see if they have been set
+  by calling param_is_set(); e.g.:
+
+	if (param_is_set(mp))
+		do_something()
+
+  The note parameter uses a special callback, json_tok_tok(). It
+  simply sets seedtok to the appropriate value and lets the handler do the
+  validating. It has the added feature of setting seedtok to NULL if it is null
+  or not specified.
+
+  There are canned failure messages for common callbacks. An example:
+
+	'msatoshi' should be an unsigned 64 bit integer, not '123z'
+
+  Otherwise a generic message is provided.
+ */
+struct param **param_parse(struct command *cmd, const char *buffer,
+			   const jsmntok_t params[], ...);
+
+/*
+ * This callback provided must follow this signature; e.g.,
+ * bool json_tok_double(const char *buffer, const jsmntok_t *tok, double *arg)
+ */
+typedef bool(*param_cb)(const char *buffer, const jsmntok_t *tok, void *arg);
+
+/*
+ * Add a handler to unmarshal a required json token into @arg. The handler must
+ * return true on success and false on failure.  Upon failure, command_fail will be
+ * called with a descriptive error message.
+ *
+ * This operation is typesafe; i.e., a compilation error will occur if the types
+ * of @arg and the last parameter of @cb do not match.
+ *
+ * Returns an opaque pointer that can be later used in param_is_set().
+ */
+#define param_req(name, cb, arg)         \
+		  param_add_(true, name, \
+			     typesafe_cb_preargs(bool, void *,       \
+						 (cb), (arg),        \
+						 const char *,       \
+						 const jsmntok_t *), \
+			     (arg))
+/*
+ * Same as above but for optional parameters.
+ */
+#define param_opt(name, cb, arg)          \
+		  param_add_(false, name, \
+			     typesafe_cb_preargs(bool, void *,       \
+						 (cb), (arg),        \
+						 const char *,       \
+						 const jsmntok_t *), \
+			     (arg))
+struct param * param_add_(bool required, char *name, param_cb cb, void *arg);
+
+/*
+ * Check to see if an optional parameter was set during parsing (although it
+ * works for all parameters).
+ * Returns the @arg if set, otherwise NULL.
+ */
+void * param_is_set(struct param *p);
+
+#endif /* LIGHTNING_LIGHTNINGD_PARAMS_H */
diff --git a/lightningd/test/run-params.c b/lightningd/test/run-params.c
new file mode 100644
index 000000000..22ddf0c07
--- /dev/null
+++ b/lightningd/test/run-params.c
@@ -0,0 +1,446 @@
+#include <signal.h>
+#include <setjmp.h>
+#include <lightningd/jsonrpc.h>
+
+#include <lightningd/params.c>
+#include <common/json.c>
+#include <common/json_escaped.c>
+#include <ccan/array_size/array_size.h>
+
+bool failed;
+char *fail_msg;
+
+struct command *cmd;
+
+void command_fail(struct command *cmd, int code, const char *fmt, ...)
+{
+	failed = true;
+	va_list ap;
+	va_start(ap, fmt);
+	fail_msg = tal_vfmt(cmd, fmt, ap);
+	va_end(ap);
+}
+
+void command_fail_detailed(struct command *cmd, int code,
+			   const struct json_result *data, const char *fmt, ...)
+{
+	failed = true;
+	va_list ap;
+	va_start(ap, fmt);
+	fail_msg = tal_vfmt(cmd, fmt, ap);
+	fail_msg =
+	    tal_fmt(cmd, "%s data: %s", fail_msg, json_result_string(data));
+	va_end(ap);
+}
+
+/* AUTOGENERATED MOCKS START */
+/* Generated stub for json_tok_wtx */
+bool json_tok_wtx(struct wallet_tx *tx UNNEEDED, const char *buffer UNNEEDED,
+		  const jsmntok_t * sattok UNNEEDED)
+{
+	abort();
+}
+
+/* AUTOGENERATED MOCKS END */
+
+struct json {
+	jsmntok_t *toks;
+	char *buffer;
+};
+
+static void convert_quotes(char *first)
+{
+	while (*first != '\0') {
+		if (*first == '\'')
+			*first = '"';
+		first++;
+	}
+}
+
+static struct json *json_parse(const tal_t * ctx, const char *str)
+{
+	struct json *j = tal(ctx, struct json);
+	j->buffer = tal_strdup(j, str);
+	convert_quotes(j->buffer);
+
+	j->toks = tal_arr(j, jsmntok_t, 50);
+	assert(j->toks);
+	jsmn_parser parser;
+
+      again:
+	jsmn_init(&parser);
+	int ret = jsmn_parse(&parser, j->buffer, strlen(j->buffer), j->toks,
+			     tal_count(j->toks));
+	if (ret == JSMN_ERROR_NOMEM) {
+		tal_resize(&j->toks, tal_count(j->toks) * 2);
+		goto again;
+	}
+
+	if (ret <= 0) {
+		assert(0);
+	}
+	failed = false;
+	return j;
+}
+
+static void zero_params(void)
+{
+	struct json *j = json_parse(cmd, "{}");
+	assert(param_parse(cmd, j->buffer, j->toks, NULL));
+
+	j = json_parse(cmd, "[]");
+	assert(param_parse(cmd, j->buffer, j->toks, NULL));
+}
+
+struct sanity {
+	char *str;
+	bool failed;
+	int ival;
+	double dval;
+	char *fail_str;
+};
+
+struct sanity buffers[] = {
+	// pass
+	{"['42', '3.15']", false, 42, 3.15, NULL},
+	{"{ 'u64' : '42', 'double' : '3.15' }", false, 42, 3.15, NULL},
+
+	// fail
+	{"{'u64':'42', 'double':'3.15', 'extra':'stuff'}", true, 0, 0,
+	 "unknown parameter"},
+	{"['42', '3.15', 'stuff']", true, 0, 0, "too many"},
+	{"['42', '3.15', 'null']", true, 0, 0, "too many"},
+
+	// not enough
+	{"{'u64':'42'}", true, 0, 0, "missing required"},
+	{"['42']", true, 0, 0, "missing required"},
+
+	// fail wrong type
+	{"{'u64':'hello', 'double':'3.15'}", true, 0, 0, "\"u64\": \"hello\""},
+	{"['3.15', '3.15', 'stuff']", true, 0, 0, "integer"},
+};
+
+static void stest(const struct json *j, struct sanity *b)
+{
+	u64 ival;
+	double dval;
+	if (!param_parse(cmd, j->buffer, j->toks,
+			 param_req("u64", json_tok_u64, &ival),
+			 param_req("double", json_tok_double, &dval), NULL)) {
+		assert(failed == true);
+		assert(b->failed == true);
+		assert(strstr(fail_msg, b->fail_str));
+	} else {
+		assert(b->failed == false);
+		assert(ival == 42);
+		assert(dval > 3.1499 && b->dval < 3.1501);
+	}
+}
+
+static void sanity(void)
+{
+	for (int i = 0; i < ARRAY_SIZE(buffers); ++i) {
+		struct json *j = json_parse(cmd, buffers[i].str);
+		assert(j->toks->type == JSMN_OBJECT
+		       || j->toks->type == JSMN_ARRAY);
+		stest(j, &buffers[i]);
+	}
+}
+
+/*
+ * Make sure toks are passed through correctly, and also make sure
+ * optional missing toks are set to NULL.
+ */
+static void tok_tok(void)
+{
+	{
+		unsigned int n;
+		const jsmntok_t *tok = NULL;
+		struct json *j = json_parse(cmd, "{ 'satoshi', '546' }");
+
+		assert(param_parse(cmd, j->buffer, j->toks,
+				   param_req("satoshi", json_tok_tok,
+					     &tok), NULL));
+		assert(tok);
+		assert(json_tok_number(j->buffer, tok, &n));
+		assert(n == 546);
+	}
+	// again with missing optional parameter
+	{
+		/* make sure it is *not* NULL */
+		const jsmntok_t *tok = (const jsmntok_t *) 65535;
+
+		struct json *j = json_parse(cmd, "{}");
+		assert(param_parse(cmd, j->buffer, j->toks,
+				   param_opt("satoshi", json_tok_tok,
+					     &tok), NULL));
+
+		/* make sure it *is* NULL */
+		assert(tok == NULL);
+	}
+}
+
+/* check for valid but duplicate json name-value pairs */
+static void dup(void)
+{
+	struct json *j =
+	    json_parse(cmd,
+		       "{ 'u64' : '42', 'u64' : '43', 'double' : '3.15' }");
+
+	u64 i;
+	double d;
+	assert(!param_parse(cmd, j->buffer, j->toks,
+			    param_req("u64", json_tok_u64, &i),
+			    param_req("double", json_tok_double, &d), NULL));
+}
+
+static void null_params(void)
+{
+	uint64_t *ints = tal_arr(cmd, uint64_t, 7);
+	/* no null params */
+	struct json *j =
+	    json_parse(cmd, "[ '10', '11', '12', '13', '14', '15', '16']");
+	for (int i = 0; i < tal_count(ints); ++i)
+		ints[i] = i;
+
+	assert(param_parse(cmd, j->buffer, j->toks,
+			   param_req("0", json_tok_u64, &ints[0]),
+			   param_req("1", json_tok_u64, &ints[1]),
+			   param_req("2", json_tok_u64, &ints[2]),
+			   param_req("3", json_tok_u64, &ints[3]),
+			   param_opt("4", json_tok_u64, &ints[4]),
+			   param_opt("5", json_tok_u64, &ints[5]),
+			   param_opt("6", json_tok_u64, &ints[6]), NULL));
+	for (int i = 0; i < tal_count(ints); ++i)
+		assert(ints[i] == i + 10);
+
+	/* missing at end */
+	for (int i = 0; i < tal_count(ints); ++i)
+		ints[i] = 42;
+
+	j = json_parse(cmd, "[ '10', '11', '12', '13', '14']");
+	struct param *four, *five;
+	assert(param_parse(cmd, j->buffer, j->toks,
+			   param_req("0", json_tok_u64, &ints[0]),
+			   param_req("1", json_tok_u64, &ints[1]),
+			   param_req("2", json_tok_u64, &ints[2]),
+			   param_req("3", json_tok_u64, &ints[3]),
+			   four = param_opt("4", json_tok_u64, &ints[4]),
+			   five = param_opt("5", json_tok_u64, &ints[5]),
+			   param_opt("6", json_tok_u64, &ints[6]), NULL));
+	assert(ints[4] == 14);
+	assert(param_is_set(four) == &ints[4]);
+	assert(!param_is_set(five));
+	assert(ints[5] == 42);
+	assert(ints[6] == 42);
+}
+
+#if DEVELOPER
+jmp_buf jump;
+static void handle_abort(int sig)
+{
+	longjmp(jump, 1);
+}
+
+static void set_assert(void)
+{
+	struct sigaction act;
+	memset(&act, '\0', sizeof(act));
+	act.sa_handler = &handle_abort;
+	if (sigaction(SIGABRT, &act, NULL) < 0) {
+		perror("set_assert");
+		exit(0);
+	}
+}
+
+static void restore_assert(void)
+{
+	struct sigaction act;
+	memset(&act, '\0', sizeof(act));
+	act.sa_handler = SIG_DFL;
+	if (sigaction(SIGABRT, &act, NULL) < 0) {
+		perror("reset_assert");
+		exit(0);
+	}
+}
+
+/*
+ * Check to make sure there are no programming mistakes.
+ */
+static void bad_programmer(void)
+{
+	u64 ival;
+	u64 ival2;
+	double dval;
+	set_assert();
+	struct json *j = json_parse(cmd, "[ '25', '546', '26' ]");
+
+	/* check for repeated names */
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("repeat", json_tok_u64, &ival),
+			    param_req("double", json_tok_double, &dval),
+			    param_req("repeat", json_tok_u64, &ival2), NULL);
+		/* shouldn't get here */
+		restore_assert();
+		assert(false);
+	}
+
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("repeat", json_tok_u64, &ival),
+			    param_req("double", json_tok_double, &dval),
+			    param_req("repeat", json_tok_u64, &ival), NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("u64", json_tok_u64, &ival),
+			    param_req("repeat", json_tok_double, &dval),
+			    param_req("repeat", json_tok_double, &dval), NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	/* check for repeated arguments */
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("u64", json_tok_u64, &ival),
+			    param_req("repeated-arg", json_tok_u64, &ival),
+			    NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	/* check for NULL input */
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req(NULL, json_tok_u64, &ival), NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req(NULL, json_tok_u64, &ival), NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	if (setjmp(jump) == 0) {
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("u64", NULL, &ival), NULL);
+		restore_assert();
+		assert(false);
+	}
+
+	if (setjmp(jump) == 0) {
+		/* Add required param after optional */
+		struct json *j =
+		    json_parse(cmd, "[ '25', '546', '26', '1.1' ]");
+		unsigned int msatoshi;
+		double riskfactor;
+		param_parse(cmd, j->buffer, j->toks,
+			    param_req("u64", json_tok_u64, &ival),
+			    param_req("double", json_tok_double, &dval),
+			    param_opt("msatoshi", json_tok_number, &msatoshi),
+			    param_req("riskfactor", json_tok_double,
+				      &riskfactor), NULL);
+		restore_assert();
+		assert(false);
+	}
+	restore_assert();
+}
+#endif
+
+static void add_members(struct param **params,
+			struct json_result *obj,
+			struct json_result *arr, unsigned int *ints)
+{
+	char name[256];
+	for (int i = 0; i < tal_count(ints); ++i) {
+		sprintf(name, "%d", i);
+		json_add_num(obj, name, i);
+		json_add_num(arr, NULL, i);
+		params[i] = param_req(name, json_tok_number, &ints[i]);
+		tal_steal(params, params[i]);
+	}
+}
+
+/*
+ * A roundabout way of initializing an array of ints to:
+ * ints[0] = 0, ints[1] = 1, ... ints[499] = 499
+ */
+static void five_hundred_params(void)
+{
+	struct param **params = tal_arr(NULL, struct param *, 500);
+
+	unsigned int *ints = tal_arr(params, unsigned int, 500);
+	struct json_result *obj = new_json_result(params);
+	struct json_result *arr = new_json_result(params);
+	json_object_start(obj, NULL);
+	json_array_start(arr, NULL);
+	add_members(params, obj, arr, ints);
+	json_object_end(obj);
+	json_array_end(arr);
+
+	/* first test object version */
+	struct json *j = json_parse(params, obj->s);
+	assert(param_parse_arr(cmd, j->buffer, j->toks, params));
+	for (int i = 0; i < tal_count(ints); ++i) {
+		assert(ints[i] == i);
+		ints[i] = 65535;
+	}
+
+	/* now test array */
+	j = json_parse(params, arr->s);
+	assert(param_parse_arr(cmd, j->buffer, j->toks, params));
+	for (int i = 0; i < tal_count(ints); ++i) {
+		assert(ints[i] == i);
+	}
+
+	tal_free(params);
+}
+
+static void sendpay(void)
+{
+	struct json *j = json_parse(cmd, "[ 'A', '123', 'hello there' '547']");
+
+	const jsmntok_t *routetok, *note;
+	u64 msatoshi;
+	unsigned cltv;
+	struct param * mp;
+
+	if (!param_parse(cmd, j->buffer, j->toks,
+			 param_req("route", json_tok_tok, &routetok),
+			 param_req("cltv", json_tok_number, &cltv),
+			 param_opt("note", json_tok_tok, &note),
+			 mp = param_opt("msatoshi", json_tok_u64, &msatoshi),
+			 NULL))
+		assert(false);
+
+	assert(param_is_set(mp));
+	assert(msatoshi == 547);
+}
+
+int main(void)
+{
+	setup_locale();
+	cmd = tal(NULL, struct command);
+	fail_msg = tal_arr(cmd, char, 10000);
+
+	zero_params();
+	sanity();
+	tok_tok();
+	null_params();
+#if DEVELOPER
+	bad_programmer();
+#endif
+	dup();
+	five_hundred_params();
+	sendpay();
+	tal_free(cmd);
+	printf("run-params ok\n");
+}