In our agency we work with lots of different clients, who usually don’t work with design software. Commenting on prototypes directly helps our workflow very much, but I can’t expect all of our clients to sign up for a sketch account.
Have you considered making a setting to let guests comment on designs in the Web App?
It’s interesting that Penpot had the same request from users and they explained a several problems related with unregistered commenting (that includes security ones and spam among others). I’m looking forward for Sketch’s team thoughts on this subject.
I absolutely need this feature. Zero of my clients work with design software and I would not ask any of them to sign up for an account in which they are automatically enrolled in a 30-day trial.
Markup.io does this well. The client enters their name and optional email address as a guest and that’s it. They can comment, reply to my comments and resolve comments. I don’t see how spam would be an issue if no one else has the share link. I have yet to experience this. Would love to hear anyone else’s take experience and/or take on this. 
Yes. We also need this function for it to replace Invision. Sketch team, make it happen pls 
Hi @mrtn
Welcome to the Forum! It’s great to have you here! Sorry about the late reply. Thanks for taking the time to share and we hear you. We’re aware there’s high interest in this feature. We need to cover several things to make it possible and also safe for all users out there. We don’t have yet an estimated date for this feature, but we’ll share any updates when possible.
About Invision, it’s interesting, because they also ask to create an account. The difference is the flow’s sequence. In an Invision prototype you can type in the comment, but when you hit “Send” you see the instructions to create an account 
and you have to create it in order to post the comment.
@technicarla, hi there! We know it may feel a bit off for some folks when they see that they are already in a trial, we’re also going through how to improve this.
I wanted to ask about your concerns with this flow: you can ignore that you’re in a trial and carry on. No need to download the app or do anything, just let the trial expire and even after that, the account will still be active and they can use it to comment after the trial has expired. Of course, we’re aware the sign up flow can improve.
From the “emotional” side, users may think they are going to have to pay after a period to be able to interact with the prototype.
Exactly right.
Yeah, makes a lot of sense. Thanks for the input @leohans and @technicarla!
While I support this request, just want to note that open source projects, or simply publicly shared projects, could be at risk of spam without account creation. One way you could solve most issues relating to spam would be to have a hidden approval process for unregistered commenters. The unregistered commenter would have no idea their comment was pending acceptance, but the project owner could see a queue of unregistered comments that are outside of the base comment queue, and accept them individually. Of course, private links probably ought not to have this by default.
Just a thought. I doubt that spam would be an issue in the vast majority of cases. Likewise, a clean and simple registration for new unregistered commenters could potentially also be a better solution.
I support this request as well. In the meantime, a minor helpful change for me would be if the comment icon were visible on public share links in prototype mode like they are in the pages view. Typically, I share the prototype link with my clients, who do not have an account initially, and they are used to switching through different prototypes. However, it’s not clear to them that they need to use the back button in the web app to open the pages to comment there, rather than directly while using the prototype. (Which is how it looks for me, when I show them the prototypes initially)
Having to switch from the prototype to the pages makes it much more difficult to provide feedback – in my case – resulting in long messages and emails with descriptions of the intended screens instead of receiving contextual feedback. InVision was much more intuitive in this regard. Clients could press the comment action, were prompted to sign up for free, and were then able to interact with my screens. Short and simple.
Hi Carmen, this is currently on the to-do list. Indeed, you should be able to have a Comment button in the prototype and start the sign up flow more easily from there.
I’ve added this post to our internal records so we can share an update when available