Track how much time it takes to solve a story in Pivotal Tracker. This browser extension generates a Toggl timer on story cards and sends all the time-tracking data with descriptions back to your Toggl account. Toggl offers free (and paid) time-tracking software with powerful reports. You can use the Toggl Button extension with Chrome and Mozilla Firefox.
This guest post explains why Toggl supports time tracking for agile teams.
Use Tracker's top-notch API documentation to make apps that best suit your needs and enhance your experience.