Highly accurate de novo polynucleotide synthesis

Methods, systems, compositions, and devices for the manufacturing of high-quality building blocks, such as polynucleotides, are described herein. Processes described herein provide for efficient washing of residual reagents, solvents, or byproducts from previous synthetic steps to allow for the generation of polynucleotides with low error rates. Processes described herein also provide for reduction in deletion rates during chemical nucleic acid synthesis. Further, methods and devices described herein allow for the rapid construction and assembly of large libraries of highly accurate polynucleotides.