Techniques and tools are described for recording input from user actions in a user interface (UI) and replicating the UI activity on a computing device. When recording and replicating UI activity, these techniques and tools improve the readability of the recorded input data and the reliability of playback. The techniques and tools may be used in combination or separately. For example, a recording tool uses a set of filters, which aggregates recorded data into basic, readable primitive methods. The recording tool converts the aggregated data into playback code by converting the playback primitive methods into corresponding computer language instructions. A playback tool may then replicate the initial recorded UI activity by playing back the computer language instructions.