diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd644085f..2c7af19fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -177,6 +177,7 @@ endif()
 
 if(CMAKE_BUILD_TYPE MATCHES "DEBUG")
   if(UNIX)
+    # FIXME: seems to not apply to library files, Issue #422
     add_compile_options(-c -Wall -Wextra -Werror -Wshadow -Wpedantic -Wunused -Wstrict-prototypes -pipe -g -O0)
     # add_compile_options(-Wconversion)
     # add_link_options(-fsanitize=address)
diff --git a/include/zenoh-pico/api/primitives.h b/include/zenoh-pico/api/primitives.h
index de9aa2bd5..bdf754c92 100644
--- a/include/zenoh-pico/api/primitives.h
+++ b/include/zenoh-pico/api/primitives.h
@@ -584,6 +584,21 @@ int8_t z_bytes_decode_into_slice(const z_loaned_bytes_t *bytes, z_owned_slice_t
  */
 int8_t z_bytes_decode_into_string(const z_loaned_bytes_t *bytes, z_owned_string_t *str);
 
+/**
+ * Decodes data into a pair of :c:type:`z_owned_bytes_t`
+ *
+ * Parameters:
+ *   bytes: Pointer to a :c:type:`z_loaned_bytes_t` to decode.
+ *   first: Pointer to an uninitialized :c:type:`z_owned_bytes_t` to contain the first element.
+ *   second: Pointer to an uninitialized :c:type:`z_owned_bytes_t` to contain the second element.
+ *   curr_idx: Pointer to the current decoding index.
+ *
+ * Return:
+ *   ``0`` if decode successful, or a ``negative value`` otherwise.
+ */
+int8_t zp_bytes_decode_into_pair(const z_loaned_bytes_t *bytes, z_owned_bytes_t *first, z_owned_bytes_t *second,
+                                 size_t *curr_idx);
+
 /**
  * Encodes a signed integer into a :c:type:`z_owned_bytes_t`
  *
@@ -752,6 +767,36 @@ int8_t z_bytes_encode_from_string(z_owned_bytes_t *bytes, const char *s);
  */
 int8_t z_bytes_encode_from_string_copy(z_owned_bytes_t *bytes, const char *s);
 
+/**
+ * Constructs payload from an iterator to `z_owned_bytes_t`.
+ * Parameters:
+ *   bytes: An uninitialized :c:type:`z_owned_bytes_t` to contain the encoded payload.
+ *   iterator_body: Iterator body function, providing data items. Returning false is treated as iteration end.
+ *   context: Arbitrary context that will be passed to iterator_body.
+ *   total_len: The length of all the items to encode.
+ *
+ * Return:
+ *   ``0`` if encode successful, ``negative value`` otherwise.
+ */
+int8_t zp_bytes_encode_from_iter(z_owned_bytes_t *bytes,
+                                 _Bool (*iterator_body)(z_owned_bytes_t *data, void *context, size_t *curr_idx),
+                                 void *context, size_t total_len);
+
+/**
+ * Append a pair of `z_owned_bytes` objects which are consumed in the process.
+ *
+ * Parameters:
+ *   bytes: An pre-initialized :c:type:`z_owned_bytes_t` to contain the encoded pair.
+ *   first: Pointer to the first `z_owned_bytes` to encode.
+ *   second: Pointer to the second `z_owned_bytes` to encode.
+ *   curr_idx: Pointer to the current encoding index value.
+ *
+ * Return:
+ *   ``0`` if encode successful, ``negative value`` otherwise.
+ */
+int8_t zp_bytes_encode_from_pair(z_owned_bytes_t *bytes, z_owned_bytes_t *first, z_owned_bytes_t *second,
+                                   size_t *curr_idx);
+
 /**
  * Checks validity of a timestamp
  *
diff --git a/src/api/api.c b/src/api/api.c
index 7ab6ce292..9bea1c9d8 100644
--- a/src/api/api.c
+++ b/src/api/api.c
@@ -337,6 +337,49 @@ int8_t z_bytes_decode_into_string(const z_loaned_bytes_t *bytes, z_owned_string_
     return _Z_RES_OK;
 }
 
+int8_t zp_bytes_decode_into_pair(const z_loaned_bytes_t *bytes, z_owned_bytes_t *first, z_owned_bytes_t *second,
+                                 size_t *curr_idx) {
+    // Check bound size
+    if (*curr_idx >= bytes->_slice.len) {
+        return _Z_ERR_GENERIC;
+    }
+    // Init pair of owned bytes
+    z_bytes_null(first);
+    z_bytes_null(second);
+    first->_val = (_z_bytes_t *)z_malloc(sizeof(_z_bytes_t));
+    second->_val = (_z_bytes_t *)z_malloc(sizeof(_z_bytes_t));
+    if ((first->_val == NULL) || (second->_val == NULL)) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    // Extract first item size
+    size_t first_len = 0;
+    // FIXME: size endianness, Issue #420
+    memcpy(&first_len, &bytes->_slice.start[*curr_idx], sizeof(uint32_t));
+    *curr_idx += sizeof(uint32_t);
+    // Allocate first item bytes
+    *first->_val = _z_bytes_make(first_len);
+    if (!_z_bytes_check(*first->_val)) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    // Extract first item data
+    memcpy((uint8_t *)first->_val->_slice.start, &bytes->_slice.start[*curr_idx], first_len);
+    *curr_idx += first_len;
+
+    // Extract second item size
+    size_t second_len = 0;
+    memcpy(&second_len, &bytes->_slice.start[*curr_idx], sizeof(uint32_t));
+    *curr_idx += sizeof(uint32_t);
+    // Allocate second item bytes
+    *second->_val = _z_bytes_make(second_len);
+    if (!_z_bytes_check(*second->_val)) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    // Extract second item data
+    memcpy((uint8_t *)second->_val->_slice.start, &bytes->_slice.start[*curr_idx], second_len);
+    *curr_idx += second_len;
+    return _Z_RES_OK;
+}
+
 int8_t z_bytes_encode_from_int8(z_owned_bytes_t *bytes, int8_t val) {
     return z_bytes_encode_from_uint8(bytes, (uint8_t)val);
 }
@@ -503,6 +546,48 @@ int8_t z_bytes_encode_from_string_copy(z_owned_bytes_t *bytes, const char *s) {
     return _Z_RES_OK;
 }
 
+int8_t zp_bytes_encode_from_iter(z_owned_bytes_t *bytes,
+                                 _Bool (*iterator_body)(z_owned_bytes_t *data, void *context, size_t *curr_idx),
+                                 void *context, size_t total_len) {
+    // Init owned bytes
+    z_bytes_null(bytes);
+    bytes->_val = (_z_bytes_t *)z_malloc(sizeof(_z_bytes_t));
+    if (bytes->_val == NULL) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    // Allocate bytes
+    *bytes->_val = _z_bytes_make(total_len);
+    if (!_z_bytes_check(*bytes->_val)) {
+        return _Z_ERR_SYSTEM_OUT_OF_MEMORY;
+    }
+    size_t curr_idx = 0;
+    while (iterator_body(bytes, context, &curr_idx))
+        ;
+    return _Z_RES_OK;
+}
+
+int8_t zp_bytes_encode_from_pair(z_owned_bytes_t *bytes, z_owned_bytes_t *first, z_owned_bytes_t *second,
+                                 size_t *curr_idx) {
+    // Calculate pair size
+    size_t first_len = z_slice_len(&first->_val->_slice);
+    size_t second_len = z_slice_len(&second->_val->_slice);
+    size_t len = 2 * sizeof(uint32_t) + first_len + second_len;
+    // Copy data
+    // FIXME: size endianness, Issue #420
+    memcpy((uint8_t *)&bytes->_val->_slice.start[*curr_idx], &first_len, sizeof(uint32_t));
+    *curr_idx += sizeof(uint32_t);
+    memcpy((uint8_t *)&bytes->_val->_slice.start[*curr_idx], z_slice_data(&first->_val->_slice), first_len);
+    *curr_idx += first_len;
+    memcpy((uint8_t *)&bytes->_val->_slice.start[*curr_idx], &second_len, sizeof(uint32_t));
+    *curr_idx += sizeof(uint32_t);
+    memcpy((uint8_t *)&bytes->_val->_slice.start[*curr_idx], z_slice_data(&second->_val->_slice), second_len);
+    *curr_idx += second_len;
+    // Clean up
+    z_bytes_drop(first);
+    z_bytes_drop(second);
+    return _Z_RES_OK;
+}
+
 _Bool z_timestamp_check(z_timestamp_t ts) { return _z_timestamp_check(&ts); }
 
 z_query_target_t z_query_target_default(void) { return Z_QUERY_TARGET_DEFAULT; }
@@ -985,9 +1070,9 @@ int8_t z_publisher_put(const z_loaned_publisher_t *pub, const uint8_t *payload,
     // Trigger local subscriptions
     _z_trigger_local_subscriptions(&pub->_zn.in->val, pub->_key, payload, len, _Z_N_QOS_DEFAULT,
                                    _z_bytes_from_owned_bytes(opt.attachment));
-
     // Clean-up
     z_encoding_drop(opt.encoding);
+    z_bytes_drop(opt.attachment);
     return ret;
 }
 
diff --git a/src/collections/slice.c b/src/collections/slice.c
index e9e24dbc2..59668747e 100644
--- a/src/collections/slice.c
+++ b/src/collections/slice.c
@@ -162,6 +162,7 @@ uint8_t _z_bytes_to_uint8(const _z_bytes_t *bs) {
     return val;
 }
 
+// FIXME: int16+ endianness, Issue #420
 uint16_t _z_bytes_to_uint16(const _z_bytes_t *bs) {
     uint16_t val = 0;
     memcpy(&val, bs->_slice.start, sizeof(val));