diff --git a/srv/format.c b/srv/format.c
index 8bdcc0d..ccf392e 100644
--- a/srv/format.c
+++ b/srv/format.c
@@ -57,8 +57,15 @@ uint32_t format_vfctprintf(FormatCallback callback, void* arg,
 	return render_format(callback, arg, format, va);
 }
 
+
 //--local functions-------------------------------------------------------------
 
+/**
+ * FormatCallback to write into a regular buffer. A pointer to BufferArg shall
+ * be passed as arg.
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 static uint32_t buffer_write(uint8_t byte, void* arg)
 {
 	struct BufferArg* buffer_arg = (struct BufferArg*)arg;
@@ -71,6 +78,12 @@ static uint32_t buffer_write(uint8_t byte, void* arg)
 	return 0;
 }
 
+/**
+ * Renders the given format to the output defined by the provided callback,
+ * formatting accordingly the provided arguments
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 static uint32_t render_format(FormatCallback callback, void* arg,
 		const char* restrict format, va_list va)
 {
@@ -157,6 +170,12 @@ static uint32_t render_format(FormatCallback callback, void* arg,
 	return 0;
 }
 
+/**
+ * Formats a signed integer and renders it to the output defined by the provided
+ * callback
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 static uint32_t render_signed(FormatCallback callback, void* arg,
 		int32_t number, uint8_t base, uint8_t width)
 {
@@ -195,6 +214,12 @@ static uint32_t render_signed(FormatCallback callback, void* arg,
 	return render_unsigned(callback, arg, (uint32_t)number, base, 0, false);
 }
 
+/**
+ * Formats an unsigned integer and renders it to the output defined by the
+ * provided callback
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 static uint32_t render_unsigned(FormatCallback callback, void* arg,
 		 uint32_t number, uint8_t base, uint8_t width, bool zero_padding)
 {
@@ -237,3 +262,4 @@ static uint32_t render_unsigned(FormatCallback callback, void* arg,
 
 	return 0;
 }
+
diff --git a/srv/format.h b/srv/format.h
index 04de136..a735542 100644
--- a/srv/format.h
+++ b/srv/format.h
@@ -20,12 +20,36 @@ typedef uint32_t (*FormatCallback)(uint8_t byte, void* arg);
 
 //--functions-------------------------------------------------------------------
 
+/**
+ * Custom implementation of snprintf. Print the given format into the given
+ * buffer with the attached arguments properly formated.
+ *
+ * This function only provided a minimal subset of the standard library's
+ * snprintf : %c, %s, %i, %d, %x as well as right-justified padding for %d and
+ * %x
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 uint32_t format_snprintf(char* restrict buffer, uint32_t buffer_size,
 		const char* restrict format, ...);
 
+/**
+ * Custom implementation of fprintf using a callback instead of a file pointer.
+ * Print the given format using the given callback with the attached arguments
+ * properly formated.
+ *
+ * This function only provided a minimal subset of the standard library's
+ * snprintf : %c, %s, %i, %d, %x as well as right-justified padding for %d and
+ * %x
+ *
+ * Returns 0 if everything went as expected, 1 otherwise
+ */
 uint32_t format_fctprintf(FormatCallback callback, void* arg,
 		const char* restrict format, ...);
 
+/**
+ * Variadic variation of format_fctprintf(), see the later for more information
+ */
 uint32_t format_vfctprintf(FormatCallback callback, void* arg,
 		const char* restrict format, va_list va);