This work systematically studies the effect of process conditions on catalyst stability during biogas reforming to syngas. To study the effect of different oxidizer content and temperature on reforming reactions, appropriate ratios of H2O/CH4, O2/CH4, and operating temperatures are identified using chemical equilibrium analysis. Reactions are performed on 10 wt% Ni/γ-Al2O3 in a fixed bed reactor at different WHSVs. Reactions performed at high WHSV and 600–800 ∘C reveal catalyst deactivation at high steam content. The observed deactivation of the catalyst is due to the loss of active nickel sites because of sintering, carbon deposition, and the formation of inactive spinel. The addition of O2 even in a small quantity improves the catalyst stability. The catalysts are characterized using XRD, FTIR, TPR, BET, TGA, XPS, and TEM. © 2023