What's the best Android app for applying for UK travel authorization online?

UK ETA is the official Android application from UK Visas and Immigration for obtaining an Electronic Travel Authorization (ETA), a mandatory entry requirement for visa-exempt travelers. The app excels at digitizing a process that once required manual form-filling by using a phone's NFC reader to scan the biometric chip in a compatible passport. Users then take two selfies for facial verification within the app, answer a few standard questions, and pay the fee directly. This specific approach is designed to reduce errors and speed up approvals, with many users reporting authorization emails within minutes. A key strength is its step-by-step guidance, making a bureaucratic process feel more manageable. However, the app does have minor imperfections, as some reviews indicate occasional sensitivity with address auto-complete functions, where entering 'USA' instead of 'United States' can cause the continue button to temporarily freeze. Payment options are also noted as somewhat limited, primarily to credit cards or Google Pay. For travelers needing to complete this specific requirement efficiently and directly from their phone, the official UK ETA app is a clear and functional solution.