Hydra : A Quantitative Overview of the World's Largest Darknet Market

We present a comprehensive description of Hydra, which was the largest darknet marketplace in the world until its shutdown in April 2022. This paper describes the main features of this online platform, such as user feedback, escrow, dispute resolution, and certification of drug quality, as well as quantitatively examining the scale and the structure of the marketplace. Using data scraped from the platform, we analyse the spatial distribution of drug listings, the variety of drug types on the platform, and the market concentration. We find that 69% of the Russian population live in a settlement where at least one drug stash was available for purchase from Hydra. While a wide variety of drugs could be traded on the platform, we observe that mephedrone, amphetamine, alpha-PVP, and MDMA together accounted for 67% of unique drug listings. The marketplace appears to have been highly competitive. We show that the dead-drop delivery system utilised on Hydra was expensive: the courier costs comprised a substantial proportion of the sale price of drugs on Hydra. Finally, examining product feedback we find that user ratings were skewed towards the highest possible rating value, similar to prior findings in relation to clearnet marketplaces