Formalin is among the highest production volume chemicals and can be obtained by several production pathways, though there are several potential production pathways in earlier development stages. To evaluate the maturity level of formalin production technologies, assessment is performed according to Technology Readiness Levels (TRL). TRL is a method used to describe the maturity of technologies, and assign them a TRL level or a range of levels from 1 to 9, with TRL 9 indicating the most mature technologic systems. Formalin is most synthesized from methanol produced via syngas which is obtained by steam reforming of natural gas. Other production pathways are formalin produced from biogas, through gasification of biomass, coal, black liquor and other, through methanol produced by direct hydrogenation of CO2 or via reverse water gas shift reaction, also known as the CAMERE process. Finally, emerging technologies such as direct conversion of methane, syngas or CO2 to formalin were considered. This work will contribute to a wider understanding of the various technologies used in the formalin production field.