diff --git a/src/assemblers.c b/src/assemblers.c
index 038e442..fdd56aa 100644
--- a/src/assemblers.c
+++ b/src/assemblers.c
@@ -26,6 +26,7 @@
 #include "public/tags.h"
 #include "public/types.h"
 
+#include <assert.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
@@ -34,7 +35,8 @@
 signed long
 Assm_user(char* buf, IRC_User* in, size_t len, bool useorig)
 {
-	if (buf == NULL || in == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(buf != NULL);
+	assert(in != NULL);
 	char* pos = buf;
 	if (in->nick == NULL && in->host != NULL) {
 		if (!safe_strcpy(&pos, in->host, len - (unsigned long) (pos - buf))) return ERR_UIRC_BUFFER_ERR;
@@ -53,7 +55,7 @@ Assm_user(char* buf, IRC_User* in, size_t len, bool useorig)
 			if (!safe_strcpy(&pos, in->host, len - (unsigned long) (pos - buf))) return ERR_UIRC_BUFFER_ERR;
 		}
 	} else
-		return ERR_UIRC_NULL_ARGS;
+		return ERR_UIRC_INVALID_FORMAT;
 	return pos - buf;
 }
 
@@ -61,7 +63,8 @@ Assm_user(char* buf, IRC_User* in, size_t len, bool useorig)
 signed long
 Assm_tags(char* buf, IRC_Tags* in, size_t len)
 {
-	if (buf == NULL || in == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(buf != NULL);
+	assert(in != NULL);
 	char*             pos      = buf;
 	struct tagmapping tagmps[] = { { .name = "time", .assg = &in->time },     { .name = "account", .assg = &in->account },
 		                       { .name = "batch", .assg = &in->batch },   { .name = "label", .assg = &in->label },
@@ -92,7 +95,8 @@ Assm_tags(char* buf, IRC_Tags* in, size_t len)
 signed long
 Assm_mesg(char* buf, IRC_Message* in, size_t len)
 {
-	if (buf == NULL || in == NULL) return ERR_UIRC_BUFFER_ERR;
+	assert(buf != NULL);
+	assert(in != NULL);
 	char*       pos = buf;
 	signed long cnt, ret;
 #ifdef UIRC_IRCV3
diff --git a/src/capabilities.c b/src/capabilities.c
index 93c757f..b11483d 100644
--- a/src/capabilities.c
+++ b/src/capabilities.c
@@ -18,6 +18,9 @@
 
 #include "public/capabilities.h"
 
+#include "public/errors.h"
+
+#include <assert.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -45,9 +48,10 @@ const char* const IRC_v3_Caps[] = {
 };
 
 #ifdef UIRC_HELPERS
-int
+signed int
 Tok_CAPS(char* caps)
 {
+	assert(caps != NULL);
 	int   temp = 0;
 	char* cur  = NULL;
 	if ((cur = strtok(caps, " ")) != NULL) {
diff --git a/src/converters.c b/src/converters.c
index 5d2a8d8..b9fd9fe 100644
--- a/src/converters.c
+++ b/src/converters.c
@@ -21,12 +21,13 @@
 #include "public/commands.h"
 #include "public/errors.h"
 
+#include <assert.h>
 #include <string.h>
 
 signed short
 Ircmd_stoi(const char* str)
 {
-	if (str == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
 	for (signed short i = UIRC_FCMD; i <= (signed short) UIRC_LCMD; i++) {
 		if (IRC_Cmds[i] != NULL && strcmp(IRC_Cmds[i], str) == 0) return i;
 	}
diff --git a/src/public/capabilities.h b/src/public/capabilities.h
index baed344..0333bb6 100644
--- a/src/public/capabilities.h
+++ b/src/public/capabilities.h
@@ -64,7 +64,7 @@ enum caps {
  * \sa caps
  * \sa https://ircv3.net/registry#capabilities
  */
-int Tok_CAPS(char* caps);
+signed int Tok_CAPS(char* caps);
 #endif /* UIRC_HELPERS */
 
 /*!
diff --git a/src/public/errors.h b/src/public/errors.h
index 613080b..cafd68a 100644
--- a/src/public/errors.h
+++ b/src/public/errors.h
@@ -20,12 +20,11 @@
 #define UIRC_GUARD_ERRORS
 
 enum uirc_errors {
-	ERR_UIRC_GENERIC = -1,
-	ERR_UIRC_NULL_ARGS = -2,
-	ERR_UIRC_INVALID_FORMAT = -3,
-	ERR_UIRC_BUFFER_ERR = -4,
-	ERR_UIRC_UNKNOWN_TOKEN = -5,
-	ERR_UIRC_VAL_FAILED = -10,
+	ERR_UIRC_GENERIC        = -1,
+	ERR_UIRC_INVALID_FORMAT = -2,
+	ERR_UIRC_BUFFER_ERR     = -3,
+	ERR_UIRC_UNKNOWN_TOKEN  = -4,
+	ERR_UIRC_VAL_FAILED     = -5,
 };
 
 #endif /* UIRC_GUARD_ERRORS */
diff --git a/src/public/tags.h b/src/public/tags.h
index f3b7657..687c6a9 100644
--- a/src/public/tags.h
+++ b/src/public/tags.h
@@ -22,7 +22,7 @@
 #define UIRC_GUARD_TAGS
 
 #ifdef UIRC_HELPERS
-size_t Assm_tag_timestamp(char* buf, size_t len, time_t time);
+ssize_t Assm_tag_timestamp(char* buf, size_t len, time_t time);
 #endif /* UIRC_HELPERS */
 
 #endif /* UIRC_GUARD_TAGS */
diff --git a/src/public/tokenizers.h b/src/public/tokenizers.h
index 425b51c..256904e 100644
--- a/src/public/tokenizers.h
+++ b/src/public/tokenizers.h
@@ -63,16 +63,16 @@ signed int Tok_mesg(char* str, IRC_Message* out);
  * \param[out] source Source of the PING (server)
  * \param[out] target Target of the PING (server or client)
  */
-void Tok_cmd_PING(IRC_Message* mesg, char** source, char** target);
+void Tok_cmd_PING(const IRC_Message* mesg, char** source, char** target);
 /*!
  * \brief Tokenizer for cases where the first argument is optional
  *
  * This function is a private helper for cases where the first argument might be missing but the second isn't
  * \param[in] mesg IRC_Message struct
- * \param[out] optarg Optional argument if given or NULL
+ * \param[out] optarg Optional argument if found or NULL
  * \param[out] target Required argument
  */
-void Tok_FArgOpt(IRC_Message* mesg, char** optarg, char** reqarg);
+void Tok_FArgOpt(const IRC_Message* mesg, char** optarg, char** reqarg);
 #endif /* UIRC_HELPERS */
 
 #endif /* UIRC_GUARD_TOKENIZERS */
diff --git a/src/public/validators.h b/src/public/validators.h
index 736fd63..0b2e8c4 100644
--- a/src/public/validators.h
+++ b/src/public/validators.h
@@ -18,14 +18,16 @@
 
 #include "types.h"
 
+#include <sys/types.h>
+
 #ifndef UIRC_GUARD_VALIDATORS
 #define UIRC_GUARD_VALIDATORS
 
-signed int Val_type_nocrlf(char* str);
-signed int Val_type_nospcl(char* str);
-signed int Val_type_noblcm(char* str);
-signed int Val_channame(char* chan);
-signed int Val_mesg(IRC_Message* mesg);
+size_t       Val_type_nocrlf(const char* str);
+size_t       Val_type_nospcl(const char* str);
+size_t       Val_type_noblcm(const char* str);
+size_t       Val_channame(char* chan);
+signed short Val_mesg(IRC_Message* mesg);
 
 #endif /* UIRC_GUARD_VALIDATORS */
 
diff --git a/src/tags.c b/src/tags.c
index d71fd28..5f473ac 100644
--- a/src/tags.c
+++ b/src/tags.c
@@ -18,12 +18,14 @@
 
 #include "public/tags.h"
 
+#include <assert.h>
 #include <time.h>
 
 #ifdef UIRC_HELPERS
-size_t
+ssize_t
 Assm_tag_timestamp(char* buf, size_t len, time_t time)
 {
+	assert(buf != NULL);
 	return strftime(buf, len, "%Y-%m-%dT%H:%M:%S.000Z", gmtime(&time));
 }
 #endif /* UIRC_HELPERS */
diff --git a/src/tokenizers.c b/src/tokenizers.c
index e87d0a8..64b506e 100644
--- a/src/tokenizers.c
+++ b/src/tokenizers.c
@@ -26,6 +26,7 @@
 #include "public/tags.h"
 #include "public/types.h"
 
+#include <assert.h>
 #include <ctype.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -36,7 +37,8 @@
 signed int
 Tok_tags(char* str, IRC_Tags* out)
 {
-	if (str == NULL || out == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
+	assert(out != NULL);
 	char *                  cval, *cpos = str, *ctag = NULL;
 	bool                    clientbound;
 	const struct tagmapping tagmps[] = {
@@ -72,6 +74,8 @@ Tok_tags(char* str, IRC_Tags* out)
 signed int
 Tok_user(char* str, IRC_User* out, bool useorig)
 {
+	assert(str != NULL);
+	assert(out != NULL);
 	char* pos = (*str == ':') ? str + 1 : str;
 	if ((out->host = strchr(pos, '@')) != NULL) *(out->host++) = '\0';
 	if (useorig && (out->orig = strchr(pos, '%')) != NULL) *(out->orig++) = '\0';
@@ -94,7 +98,8 @@ Tok_user(char* str, IRC_User* out, bool useorig)
 signed int
 Tok_mesg(char* str, IRC_Message* out)
 {
-	if (str == NULL || out == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
+	assert(out != NULL);
 	int   ret;
 	char *progr = str, *command;
 #ifdef UIRC_IRCV3
@@ -113,10 +118,9 @@ Tok_mesg(char* str, IRC_Message* out)
 			if ((ret = Tok_user(prefix, &out->name, false)) < 0) return ret;
 		} else
 			return ERR_UIRC_INVALID_FORMAT;
+		skip_spaces(&progr);
 	}
 
-	skip_spaces(&progr);
-
 	if (isalnum(*progr) && (command = strtok_mr(&progr, " ")) != NULL) {
 		signed short temp;
 		if (isalpha(*command)) {
@@ -130,7 +134,6 @@ Tok_mesg(char* str, IRC_Message* out)
 		}
 	} else
 		return ERR_UIRC_INVALID_FORMAT;
-
 	skip_spaces(&progr);
 
 	short i;
@@ -150,8 +153,11 @@ Tok_mesg(char* str, IRC_Message* out)
 
 #ifdef UIRC_HELPERS
 void
-Tok_cmd_PING(IRC_Message* mesg, char** source, char** target)
+Tok_cmd_PING(const IRC_Message* mesg, char** source, char** target)
 {
+	assert(mesg != NULL);
+	assert(source != NULL);
+	assert(target != NULL);
 	*source = (mesg->args[0] == NULL && mesg->trailing) ? mesg->args[2] : (mesg->args[1] != NULL) ? mesg->args[0] : NULL;
 	*target = (mesg->args[1] == NULL) ? mesg->args[0] : mesg->args[1];
 }
@@ -161,8 +167,11 @@ Tok_cmd_PING(IRC_Message* mesg, char** source, char** target)
  */
 
 void
-Tok_FArgOpt(IRC_Message* mesg, char** optarg, char** reqarg)
+Tok_FArgOpt(const IRC_Message* mesg, char** optarg, char** reqarg)
 {
+	assert(mesg != NULL);
+	assert(optarg != NULL);
+	assert(reqarg != NULL);
 	*optarg = (mesg->args[1] != NULL) ? mesg->args[0] : NULL;
 	*reqarg = (mesg->args[1] != NULL) ? mesg->args[1] : mesg->args[0];
 }
diff --git a/src/validators.c b/src/validators.c
index 8d19f84..1b32152 100644
--- a/src/validators.c
+++ b/src/validators.c
@@ -21,45 +21,50 @@
 #include "public/errors.h"
 #include "public/types.h"
 
+#include <assert.h>
 #include <stdio.h>
 #include <string.h>
 
-signed int
-Val_type_nocrlf(char* str)
+size_t
+Val_type_nocrlf(const char* str)
 {
-	if (str == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
+	const char* save = str;
 	for (; *str; str++) {
 		if (*str == '\r' || *str == '\n') return 0;
 	}
-	return 1;
+	return str - save;
 }
 
-signed int
-Val_type_nospcl(char* str)
+size_t
+Val_type_nospcl(const char* str)
 {
-	if (str == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
+	const char* save = str;
 	for (; *str; str++) {
 		if (*str == ' ' || *str == ':') return 0;
 	}
-	return 1;
+	return str - save;
 }
 
-signed int
-Val_type_noblcm(char* str)
+size_t
+Val_type_noblcm(const char* str)
 {
-	if (str == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(str != NULL);
+	const char* save = str;
 	for (; *str; str++) {
 		if (*str == '\a' || *str == ',') return 0;
 	}
-	return 1;
+	return str - save;
 }
 
-signed int
+size_t
 Val_channame(char* chan)
 {
-	if (chan == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(chan != NULL);
 	if (*chan != '#' && *chan != '+' && *chan != '!' && *chan != '&') return 0;
-	char* clps = ++chan;
+	const char* save = chan;
+	char*       clps = ++chan;
 	if ((clps = strchr(chan, ':')) != NULL) {
 		*clps = '\0';
 		if (Val_type_nospcl(chan) != 1 || Val_type_nocrlf(chan) != 1 || Val_type_noblcm(chan) != 1) {
@@ -70,13 +75,14 @@ Val_channame(char* chan)
 		chan  = ++clps;
 	}
 	if (Val_type_nospcl(chan) != 1 || Val_type_nocrlf(chan) != 1 || Val_type_noblcm(chan) != 1) return 0;
-	return 1;
+	return save - chan;
 }
 
-signed int
+// TODO: Work on the logic for this
+signed short
 Val_mesg(IRC_Message* mesg)
 {
-	if (mesg == NULL) return ERR_UIRC_NULL_ARGS;
+	assert(mesg != NULL);
 	for (unsigned int i = 0; mesg->args[i] != NULL; i++) {
 		if (Val_type_nocrlf(mesg->args[i]) != 1) return ERR_UIRC_VAL_FAILED;
 		if (!(mesg->args[i + 1] == NULL && mesg->trailing)) {