In the context of Making Tax Digital, a bridging tool (or bridging software) is a small piece of software designed to create the final digital link between your business and HMRC so you can report your taxes digitally, as the legislation demands.
Notably, a bridging tool doesn’t take care of the other requirements for Making Tax Digital, such as digital record keeping, and it doesn’t ensure your systems are digitally linked.
This is why many suggest bridging tools shouldn’t be used as anything other than a very temporary stopgap measure.