Systems and techniques are provided for implementing multiprotocol label switching (MPLS) header extensions. In some examples, a method can include, receiving, by a router of a MPLS network, a data packet. In some aspects, the method can include adding, by the router of the MPLS network, at least one entry to an MPLS stack of the data packet, wherein the at least one entry includes an MPLS extension indicator (MEI) that is associated with at least one of an in-stack extension header presence indicator (IPI) and a bottom-of-stack extension header presence indicator (BPI). In some examples, the method can include adding, based on the IPI and the BPI, at least one of an in-stack extension header and a bottom-of-stack extension header to the MPLS stack of the data packet.