You may have heard of Boomerang before, a great Gmail and Outlook plug-in that lets you schedule emails to send at optimal times, snooze messages, get read receipts & follow up reminders. Now, the company behind it has launched a new tool that uses machine learning to help you write better messages that are more likely to get a response.

Respondable analyzes your message as you type and gives it a rating based on several different parameters including things like subject length and word count, as well as more subjective ones like positivity, politeness, and subjectivity. Obviously, you don’t have to adhere strictly to Respondable’s suggestions, but the idea is to keep these color-coded parameters in the green as best you can to improve your chances of getting a response.

The new feature is rolling out with a new version of Boomerang. Respondable's basic assessment tools — subject length, word count, question count, and reading level — are free. For more advanced parameters you’ll need a subscription to Boomerang for Gmail’s Pro and Premium plans, starting at $15 per user per month.

Boomerang is available for all major browsers (except Edge) and Microsoft Outlook. If a big part of your job involves sending emails, then Respondable could be well worth a shot. Just keep in mind that the tool isn’t meant to do anything about bad grammar or punctuation.