Aligning development and deployment of compostable plastics for meaningful impact

<h2>Summary</h2> Compostable plastics are an alternative to conventional plastics, but their environmental value is debated. Although designed to biodegrade under controlled conditions, their real-world performance depends on both material properties and waste-management systems. This primer elaborates the development and deployment of compostable plastics as a conditional strategy for reducing plastic pollution and achieving broader waste-reduction goals by reviewing material-design considerations, system-performance challenges, and regulatory requirements that shape market entry and credibility, highlighting food-contact authorizations as a key example. By outlining these challenges and requirements, this primer aims to help researchers and developers align material innovation with regulatory pathways and end-of-life realities. This resource aims to support researchers, developers, and policymakers working to create and commercialize effective, safe, and fit-for-purpose compostable plastic solutions.