Off-grid solar solutions provide the cheapest and fastest way to electrify hundreds of millions of homes and businesses -- and yet over 100 million people will still be unable to afford them in 2030. It is increasingly clear that we need to bridge this ‘affordability gap’, and end-user subsidies, which directly reduce costs for consumers, will play a key role. However, to avoid market distortion - which can hamper other energy access efforts - such subsidies must be designed carefully. To enable stakeholders to jointly design smart and effective end user subsidies, GOGLA, ESMAP/Lighting Global, EnDev and Africa Clean Energy (ACE), have created the End User Subsidy Lab: pooling knowledge, technical expertise, and funding. We welcome all stakeholders to contribute to the Lab with resources available to them, be it knowledge, expertise, or financial contributions.