UCSC Genome API
The UCSC Genome Browser as an API — reference genome data for hundreds of species, from the renowned UCSC Genome Browser at UC Santa Cruz. /v1/genomes lists the 220+ genome assemblies UCSC hosts, each with its assembly id (such as hg38 for human, mm39 for mouse, danRer11 for zebrafish), organism, description and data source. /v1/chromosomes?genome=hg38 returns an assembly's chromosomes and sequences with their sizes in base pairs, largest first. /v1/sequence?genome=hg38&chrom=chrM&start=0&end=100 retrieves the raw DNA sequence of any genomic region (0-based start, half-open end; regions are capped at 100,000 bases per call). Assembly ids come from /v1/genomes and chromosome names look like chr1, chrX or chrM. Ideal for bioinformatics pipelines, genome-visualisation and primer-design tools, region and sequence lookups, comparative genomics and teaching. Data from the UCSC Genome Browser (free for academic, non-profit and personal use). This is the genome browser's assemblies and raw reference sequence — distinct from gene-annotation and protein-sequence databases such as Ensembl, UniProt and ENA.
api.oanor.com/ucsc-api