The US National Institutes of Health provides public REST APIs for biomedical research
NCBI E-utilities (Entrez Programming Utilities)
Programmatic access to all Entrez databases including PubMed, PMC, Gene, Nuccore, and Protein
Access to biological datasets including gene metadata, genome assemblies, taxonomy, and virus genomes
Programmatic access to PubChem chemical compound data and bioassay information
Access to federally and privately supported clinical studies data
Programmatic access to NIH-funded research project data including grants and publications
Submit BLAST sequence searches and retrieve alignment results
Access to PubMed Central Open Access content and ID conversion