MobileGym: A Verifiable and Highly Parallel Simulation Platform for Mobile GUI Agent Research

Dingbang Wu, Rui Hao, Haiyang Wang, Shuzhe Wu, Han Xiao, Zhenghong Li, Bojiang Zhou, Zheng Ju, Zichen Liu, Lue Fan, Zhaoxiang Zhang


Abstract
We present MobileGym, a browser-hosted, lightweight, fully controllable simulation platform for everyday mobile use, targeting interaction fidelity without replicating proprietary backends. It enables two capabilities previously out of reach for everyday apps: verifiable outcome signals through deterministic state-based judging over structured JSON state, and scalable online RL through low-cost parallel rollouts. The full environment state is captured, configured, forked, and compared as structured JSON, and a single server can host hundreds of parallel instances (400 MB each, 3 s cold start). A layered state model and a declarative task-definition framework keep state programmability and task creation practical at scale, and a single programmatic judging mechanism delivers both deterministic evaluation verdicts and dense RL rewards. The accompanying MobileGym-Bench provides 416 parameterized task templates (256 test + 160 train) over 28 apps, with deterministic judges and a structured AnswerSheet protocol that avoids free-text matching failures. In a Sim-to-Real case study, GRPO on Qwen3-VL-4B-Instruct gains +12.8 pt on the 256-task test set, and on a 59-task real-device signal subset, real-device execution retains 95.1% of the simulation-side training gain.
Anthology ID:
2026.emnlp-main.1009
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
23223–23247
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URL:
https://aclanthology.org/2026.emnlp-main.1009/
DOI:
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Cite (ACL):
Dingbang Wu, Rui Hao, Haiyang Wang, Shuzhe Wu, Han Xiao, Zhenghong Li, Bojiang Zhou, Zheng Ju, Zichen Liu, Lue Fan, and Zhaoxiang Zhang. 2026. MobileGym: A Verifiable and Highly Parallel Simulation Platform for Mobile GUI Agent Research. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 23223–23247, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
MobileGym: A Verifiable and Highly Parallel Simulation Platform for Mobile GUI Agent Research (Wu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1009.pdf