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Online RL on live iOS apps trained 8B UI-navigation agents that nearly sevenfolded out-of-distribution transfer to Android, and beat Gemini-3.5-Flash

AspireAI community · arXiv (UI navigation RL authors)
Frontier VLMs navigate interfaces well but cost too much for everyday use, while smaller models trained by supervised fine-tuning memorise static trajectories and cannot recover from an error. This work trains UI navigation agents with online reinforcement learning directly on live iOS applications, splitting the agent into a Planning component and a UI Grounding model, using an LLM-as-a-Judge to supply both step-level and terminal rewards, and adding GiGPPO, a neighbour-conditioned value estimate that uses visually similar states across concurrent trajectories to stabilise the critic. On UINavBench, iOSWorld and AndroidWorld the agents substantially beat SFT and terminal-only RL; the 8B RL agents show nearly a sevenfold improvement over the SFT baseline on out-of-distribution Android transfer, outperform Gemini-3.5-Flash and tie Gemini-3.1-Pro on real iOS apps. The training infrastructure orchestrates hundreds of concurrent virtual iOS devices.
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