We study the large-scale experimental rollout of a platform that reduced search and matchingfrictions in Ugandan agricultural markets by connecting buyers and sellers. Market integrationimproved substantially: trade increased and price gaps fell. Interpreting the experiment througha trade model, we estimate treatment effects accounting for equilibrium changes that impactcontrol markets. The intervention reduced fixed trade costs by 20% and increased trade flowsbetween treated markets by 7% and across all markets by 1%. Scale economies shaped engagement:few farmers used the platform, but equilibrium price convergence from improved arbitrage bylarger traders passed through to farm revenue.