https://reviewable.io https://reviewable.io is the earliest full-powered Critique alternative for GitHub. It supports some cool things Critique doesn't/didn't,

https://reviewable.io https://reviewable.io is the earliest full-powered Critique alternative for GitHub. It supports some cool things Critique doesn't/didn't, such as reviewing multi-commit branches (also across history-rewriting force-push cleanups), and indicating exactly the nature of your comment (just FYI, or you want this to be changed before you'll give your approval). (I was an intern in the initial making of Critique, and subsequently got interested in finding an out-of-Google alternative. I contributed a bit to other review tools such as ReviewBoard, and actively used Gerrit, Crucible, Phabricator, and GitLab reviews.) When looking for a Critique alternative for my startup, reviewable.io had just appeared and ticked all the boxes, and we use it successfully for many years. The drawbacks are that it's GitHub-only and isn't free software.