single tube long fragment read (stLFR) technology enables efficient WGS, haplotyping, and contig scaffolding. It is based on adding the same barcode sequence to sub-fragments of the original DNA molecule (DNA co-barcoding). To achieve this, stLFR uses the surface of microbeads to create millions of miniaturized compartments in a single tube. Using a combinatorial process over 1.8 billion unique barcode sequences were generated on beads, enabling practically non-redundant co-barcoding in reactions with 50 million barcodes. Using stLFR we demonstrate efficient unique co-barcoding of over 8 million 20-300 kb genomic DNA fragments with near perfect variant calling and phasing of the genome of NA12878 into contigs up to N50 23.4 Mb. stLFR represents a low-cost single library solution that can enable long sequence data.