BillGrid.com - BillGrid is an easy to use online invoicing, billing and expense management system that will save you time with tracking clients projects, expenses, invoices and payments.
Google Analytics - Improve your website to increase conversions, improve the user experience, and make more money using Google Analytics. Measure, understand and quantify engagement on your site with customized and in-depth reports.
ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
StatCounter - StatCounter is a simple but powerful real-time web analytics service that helps you track, analyse and understand your visitors so you can make good decisions to become more successful online.
Elorus - A super-easy online invoicing & time tracking software
Matomo - Matomo is an open-source web analytics platform