What is the difference between UCCJEA and UIFSA?

UCCJEA

UCCJEA stands for "Uniform Child Custody Jurisdiction and Enforcement Act" and is a set of laws that have been adopted by all U.S. states (with the exception of Massachusetts). The purpose of the UCCJEA is to provide guidelines for determining which state has jurisdiction over child custody cases when the parents live in different states or when a child has been taken across state lines. The UCCJEA aims to prevent multiple states from issuing conflicting custody orders, and to ensure that the custody decision is made in the child's "home state" - the state where the child has lived for at least six months before the custody proceeding.

Source: American Bar Association. "Uniform Child Custody Jurisdiction and Enforcement Act (UCCJEA)." https://www.americanbar.org/groups/family_law/publications/family-advocate/2020/fall-2020/uniform-child-custody-jurisdiction-and-enforcement-act-uccjea/

UIFSA

UIFSA stands for "Uniform Interstate Family Support Act" and is a set of laws that have also been adopted by all U.S. states (including Massachusetts). UIFSA deals with the issue of child support, including the enforcement and modification of child support orders when the parents live in different states. The purpose of UIFSA is to provide a consistent framework for determining which state has jurisdiction to establish, modify, and enforce child support orders, and to ensure that child support obligations are met across state lines.

Source: National Conference of State Legislatures. "Uniform Interstate Family Support Act (UIFSA)." https://www.ncsl.org/research/human-services/uniform-interstate-family-support-act-uifsa.aspx