Reddit exodus - Using Lemmy from my existing Mastodon

Many are turning to Lemmy as a viable Reddit alternative. Here is how to use your existing Mastodon account with Lemmy.

Reddit exodus - Using Lemmy from my existing Mastodon

By now most of you have probably heard about Reddit blackout/exodus and you may also have heard about Lemmy, a Fediverse alternative to Reddit, which many have flocked to.

So like many people right now, I wanted to check out Lemmy as a viable alternative to Reddit, and also, like many existing Mastodon users I'm thinking:

Do I need to create a new Lemmy account on another instance, or can I just use my existing Mastodon account to do everything on Lemmy?

As an avid Fediverse user, my primary identity is on a Mastodon server.  Since Lemmy uses ActivityPub, I thought that maybe I can just cross post into Lemmy (just like I would cross post into another Mastodon instance) despite it being a quite different type of app (basically like Fediverse Reddit vs Fediverse Twitter).

It turns out... It works!!

Yes, it's possible to upvote, post, reply and follow anything on Lemmy, through my existing Mastodon account, using the same cross posting method you would between different Mastodon instances, with a few notes:

  • Mastodon Favorites are counted as Lemmy Upvotes (however Mastodon Boosts do NOT seem to count).
  • Creating a Mastodon post while mentioning a Lemmy community/topic will create a discussion post within the Lemmy Community, with the first line of the Mastodon post becoming the discussion post's title.

🤔 Can't I just "log into" a Lemmy server with my Mastodon account?

No it is not possible nor necessary to log into another server to post into it. Remember, just like cross-posting between different Mastodon servers, you do not need to log into another server using your existing Mastodon account, and the same applies to Lemmy servers. It can take some time to get your head around this, as we are normally used to siloed apps where you actually need to log into the other app using your existing account to do anything. This is the Fediverse, so it works little differently, and actually its simpler once you get used to it. Since all these apps are built on the same protocol (ActivityPub), they can all talk to each other directly, although the information is presented in different ways in different apps.

Performing Actions on Lemmy via Mastodon

Here are some longer instructions for various actions:

The Rainbow Fediverse button will give you the direct link to reply to. Both the links are often the same if the author is a member of the current instance.

TIP: When you copy and paste links, always use the "Direct Link" from the OP's instance, as demonstrated in the above image.

  • Browsing Lemmy groups (called Communities): works without logging in, directly on the Lemmy instance.
  • Replying to a Lemmy post/comment: Get the direct link to the Lemmy post/comment using its "rainbow Fediverse" link button in Lemmy, paste it into your logged in Mastodon instance search bar, and then press Reply and post your reply.
  • Upvote a post or comment: I again get the direct link to the Lemmy discussion or comment and paste into my Mastodon instance search bar, then I click the Mastodon favorite button (note that this might not be as private as using an actual Lemmy account to upvote).
  • Follow a Lemmy account, post or community: again just get its Lemmy direct link, paste into your Mastodon search field and follow.  Lemmy groups automatically boost any new posts so you will see them appear in your Mastodon feed.
  • Post a new discussion to a group: you simply create a new post in Mastodon, and @ mention the Lemmy group you want to post into, where the first line will become the title of the post. An example (although I suggest doing the @ mention on its own line at the end of the post so you don't mess up the post title). An easy way is to again paste the direct link to the group in Mastodon, and go to that groups profile and click the 3 dots menu and click Mention.  If you attach an image or link to the post, it appears as the posts thumbnail and can be viewed by clicking on it in the post on Lemmy.
A Mastodon post I made on the left, and how it shows up in the Lemmy instance on the right. Note my Favorite shows up as an Upvote in Lemmy.


  • Downvotes are not possible via Mastodon, as far as I can tell.
  • Images attached to replies to posts don't seem to show up in Lemmy, even though they do work when attached to an original post in a community.  One workaround is to make the reply then get a direct link to the image, go back end edit the reply, pasting that link into its text so people viewing it on Lemmy can still access the image (but this way there is no preview of it, as there is in Mastodon).
  • Can't follow group posts only.  When you follow a group/community in Lemmy you see all of the posts and replies made in that group (via automatic boosts), which can quickly clutter up your feed. I can't find a simple way to only show new posts and not all the replies.  So now I mainly browse Lemmy on its own instance page and only drop into Mastodon to make replies and upvotes.

A bit Clunky? This should improve soon...

Currently it requires copy and pasting links, the same as manually cross-posting between Mastodon instances when you don't have a browser extension like FediAct installed.  Extensions like FediAct embed buttons into foreign Mastodon pages which invisibly automates the copy/pasting for a completely seemless experience across instances.

Rest assured, given the latest spike in interest in Lemmy, it is likely the community will respond with a similar browser extension which will eliminate the manual copy/paste steps by embedding buttons into Lemmy pages.  Stay tuned, as I will update this post once I find an extension to simplify things.