Lemmy Guide: The Federated Reddit (2026)

Lemmy is the federated answer to Reddit: link aggregation, threaded comments, and up/down voting, but spread across hundreds of independently operated servers instead of one company. It is also small. Roughly 48,600 monthly active users across about 455 instances as of December 2025, against Reddit's 100 million plus daily actives.¹ That is approximately one one-thousandth of Reddit's scale, and this guide will not pretend otherwise.

The honest scale story is exactly why Lemmy is worth understanding. Its user base is one of the most concentrated pools of developers, sysadmins, self-hosters, and privacy-conscious buyers anywhere on the social web, and its architecture (open protocol, open API, no ads, no engagement algorithm) makes it structurally different from every mainstream platform. If your product or content lives anywhere near open source, self-hosting, Linux, or privacy, Lemmy punches far above its headcount. If you show up with mass-market marketing instincts, you will be banned within a week.

This guide covers how Lemmy actually works (instances, federation, sorting), who is on it, what the numbers honestly say, and how to post there without tripping its famously strict self-promotion norms.

What is Lemmy?

Lemmy is open-source link-aggregator software: users post links, images, or Markdown text into topic-based communities, and other users vote and comment in threaded discussions. Anyone can run their own Lemmy server (an "instance"), and instances federate with each other over ActivityPub, the same protocol Mastodon uses. The result is a single connected network, sometimes called the "threadiverse," assembled from independent servers with their own domains, admins, and rules.²

The project was created by a pseudonymous developer known as Dessalines, with a first commit in February 2019 and an initial release in May 2019; a second lead developer, Nutomic, joined around 2020.³ The backend is written in Rust, the frontend in TypeScript and React, and the whole codebase is licensed under the AGPLv3.⁴

Lemmy's positioning is unambiguous. The project site, join-lemmy.org, promises "no advertising, monetizing, or venture capital, ever."⁵ Development has been funded by a 45,000 euro grant from the NLnet Foundation in 2020, which allowed both lead developers to work full-time,⁶ plus ongoing donations via Open Collective and Liberapay.⁷

Even the name follows fediverse convention rather than marketing logic. Asked about it in 2020, Dessalines said: "It was nameless for a long time, but I wanted to keep with the fediverse tradition of naming projects after animals."⁴ That is a small detail, but it is consistent with everything else about the project: built by and for people who wanted an alternative to corporate social media, not a startup chasing a category.

On versions: development through 2025 focused on the long-awaited 1.0 milestone, including database and pagination rewrites, multi-communities, and post tags. A 1.0.0-beta.1 arrived around July 2026, but as of this writing the latest stable release is still in the 0.19.x line and 1.0 final has not shipped.⁸ The 1.0 release will bring breaking API changes, which matters if you build tooling against Lemmy (more on the API below).⁹

Key Lemmy statistics

A note on freshness: the most recent hard MAU snapshot available is from December 2025. For live numbers, check FediDB, Fediverse Observer, or the-federation.info, which track the network continuously.¹⁰

The honest scale story

Lemmy's growth curve has exactly one spike, and it has a date.

Before June 2023, Lemmy was tiny: well under 100 instances, a hobby project known mostly inside the fediverse.¹ Then Reddit announced API pricing that killed most third-party Reddit apps, moderators went on strike, and a wave of Reddit users went looking for an exit. Lemmy was the closest structural match, and its monthly active users spiked to an all-time high of roughly 72,600 in mid-2023.¹¹ Reddit briefly banned users for promoting Lemmy during the exodus, then reversed course after the bans drew attention on Hacker News.¹

The wave receded. By July 2024 the network was around 64,900 MAU and declining.¹² By December 2025 it had settled to roughly 48,600. That is not collapse; it is a settling to a durable core, the users for whom federation and no-ads are the point rather than a protest gesture.

The network also took a structural hit in 2025: lemm.ee, long the second-largest instance, shut down on June 30, 2025, with the admin citing volunteer burnout. Users were told to export their settings and migrate.¹³ The shutdown illustrates both the fragility of volunteer-run infrastructure and, more positively, that the network survived losing its number two server, because accounts and communities exist elsewhere.

So the honest framing: Lemmy is roughly 1/1000th of Reddit. What is left after the exodus settled is unusually dense in exactly the audiences that are hardest to reach through ads: developers, sysadmins, self-hosters, and privacy-first buyers. Small is not the same as worthless; it is a different kind of channel entirely. Our post on matching content to platform makes the general case; Lemmy is the extreme example.

How Lemmy works

Instances and addressing

Every Lemmy instance is an independent server with its own domain, admins, and rules. But an account on one instance can browse, subscribe to, and post in communities across the whole federated network.²

The addressing scheme has two parts because names alone are ambiguous across servers:

• Communities: !community@instance.tld, for example !selfhosted@lemmy.world
• Users: @user@instance.tld

There can be a technology community on several instances at once; the address tells you which one you mean.

Federation via ActivityPub

Under the hood, Lemmy federates over ActivityPub. Users are Person actors and communities are Group actors. When someone posts to a community, the community actor "announces" (boosts) that post and its comments to every instance with subscribers, which is how a thread stays synchronized across hundreds of servers.¹⁴

This design has a nice side effect: Mastodon interoperability. From a Mastodon account you can follow a Lemmy community, and new posts arrive in your timeline as boosts. Reply to one and your reply becomes a comment on the Lemmy thread. You can even create a Lemmy text post from Mastodon by @-mentioning the community, with the first line becoming the title. The big gap: link posts cannot be created from Mastodon, and the experience is generally clunky rather than seamless.¹⁵ If you are already active in the Mastodon world, our Mastodon guide covers that side of the fence.

Voting and sorting

Lemmy keeps Reddit's up/down voting, federated as ActivityPub Like and Dislike activities. Some instances disable downvotes entirely as a culture decision.¹⁶

Sorting is where Lemmy is refreshingly transparent, because the algorithms are documented and open source:¹⁶

• Hot: post score decayed by time since posting
• Active: like Hot, but a post is bumped by recent comments, keeping live discussions visible
• Top: raw score over a chosen window
• New: chronological
• Scaled: Hot divided by log(2 + users_active_month) of the community, deliberately boosting posts from smaller communities so the big ones do not monopolize every feed¹⁷

There is no ads-driven ranking, no tracking, and no engagement-optimizing feed. What you subscribe to is what you see, sorted by a formula you can read.

Moderation and defederation

Moderation happens at two levels: community moderators handle their own communities, and instance admins set server-wide policy. The distinctive federated tool is defederation: an instance can cut ties with another instance entirely, so their users and content stop flowing to each other.

Two well-known examples: Beehaw defederated from lemmy.world and sh.itjust.works in June 2023, because those instances' open signups created a moderation load Beehaw's team could not absorb.¹⁸ And most mainstream instances block lemmygrad.ml, an explicitly Marxist-Leninist instance, on political and moderation grounds.¹ Defederation means "the network" looks slightly different depending on where your account lives, which is worth checking before you pick a home instance.

Who is on Lemmy

Lemmy's culture is the product of its history: built by FOSS developers, populated by a Reddit exodus that selected for people angry about API lockdown and corporate control.

The skew is heavily technical. Linux, selfhosted, privacy, open source, gaming, and technology are the consistently thriving topics, along with an assortment of niche fandoms. There is an entire instance, programming.dev, dedicated to developers. lemmy.ml, the original flagship, was founded as a server for "leftist privacy and FOSS enthusiasts."¹⁹

The political lean is real and worth stating neutrally. The overall network skews left-of-center, and the lead developers openly identify as Marxist-Leninists. Two instances, hexbear.net and lemmygrad.ml, are explicitly Marxist and are widely defederated by the rest of the network.¹⁹ The flagship general-purpose instances (lemmy.world, lemmy.ca, feddit.org, sh.itjust.works, programming.dev) are more moderate and general-interest, and that is where most of the audience actually is.

The ethos is anti-corporate and anti-advertising, and users enforce it socially. This is a network run by volunteers who chose it specifically to get away from monetized feeds; the lemm.ee burnout shutdown shows both the commitment and the cost.¹³ Dessalines has been explicit that growth is not the goal: "we were not willing to sacrifice our values for growth's sake," and his stated biggest fear is "a centralization onto one big server, that tries to replicate all the worst things and behaviors about reddit."²⁰

For a brand or creator, the practical read: this audience is small, expert, skeptical of marketing, and extremely valuable if you have something genuinely relevant to them, especially open source or self-hostable software.

Content formats and the API

Lemmy supports four post shapes:

• Link posts: a URL plus a title, the classic aggregator format
• Text posts: title plus a full Markdown body
• Image posts: image upload with title
• Combined: a URL with a Markdown body attached

Markdown support is complete (headings, tables, code blocks), which suits the technical audience. Posts and communities can carry NSFW flags. There is no native video hosting in practice; video content is shared as link posts to YouTube or PeerTube.²

On the developer side, Lemmy exposes a full HTTP REST API covering everything the UI does: posts, comments, votes, moderation, community management.²¹ The official TypeScript client is lemmy-js-client, and the lemmy-bot npm package wraps common bot patterns. Authentication is a login call that returns a JWT, sent as a bearer token thereafter. One caution worth repeating: the 1.0 release brings breaking API changes, so pin your client versions.⁹

This matters for anyone building on top of Lemmy rather than just posting to it. Because the API is genuinely complete rather than a read-only subset, it is possible to build entire alternative front ends, moderation bots, cross-posting tools, and archival scrapers against it without asking permission from anyone. That openness is a direct consequence of the AGPLv3 license and the no-venture-capital funding model: there is no platform business to protect by locking the API down.

There is no native post scheduling in the Lemmy UI. Because the API is complete, schedulers can fill that gap; posterly's Lemmy scheduler lets you queue link and text posts to specific communities alongside your other 17 platforms, from $7/month.

How to post on Lemmy without getting banned

This is the section that saves you from wasting the channel. Lemmy's self-promotion norms are stricter than almost any mainstream platform, and enforcement is fast.

The sitewide baseline. lemmy.world's terms of service state plainly that it is "not a free advertising platform." Accounts whose activity is majority-commercial get removed, and posting identical content across many communities is treated as spam.²²

The community-level pattern. The clearest published example is !selfhosted@lemmy.world, whose rules cap self-promotional posts at roughly 10% of your activity, require the account to be at least 30 days old, and require active participation in the community beyond your own links. Notably, fully open-source, free, self-hostable projects are exempt from the promotion limits there.²³ That exemption is community-specific, not universal, but the underlying pattern (participate first, promote sparingly, FOSS gets more grace) generalizes across the network.

Bot rules are explicit. On lemmy.world, bots must be flagged as bots in their profile, carry owner contact info in the bio, obtain explicit permission from the moderators of any community they post in, and must not advertise.²⁴ If you are tempted to wire up lemmy-bot to blast announcements, get mod permission first or expect an instance-level ban.

How OSS projects do it right. The working playbook, visible every week in the wild: announce releases as a link or text post in the relevant communities (!selfhosted, !opensource, !linux, or your project's own community), write the post like a changelog rather than a pitch, and have the maintainer stay in the comments answering questions. Lemmy users reward maintainers who engage and are blunt with ones who post and vanish.

Distilled into rules of thumb:

1. One community per post. Cross-post manually and sparingly, with context, or not at all; identical mass cross-posting reads as spam.²²
2. Participate before you promote. Comment, answer questions, vote. A 30-day-old account with real history is the effective entry ticket.²³
3. Stay near the 10% line. If most of your post history is your own product, you are a commercial account and will be treated as one.
4. Disclose affiliation. "I'm the maintainer" earns goodwill; discovered stealth marketing earns a ban and a public thread about you.
5. Expect blunt feedback. Technical audiences will critique your stack, your license, and your pricing in the comments. Engaging honestly is the growth mechanic.

This is slower than paid reach. It is also why recommendations on Lemmy carry unusual weight: nobody is paid to be there.

Lemmy vs Reddit vs Mbin vs PieFed vs Discourse

vs Reddit. Reddit has 100M+ daily actives, advertising, algorithmic feeds, and a paid API since 2023. Lemmy has roughly 50K monthly actives, no ads, a fully open API, and no owner. Reddit wins on raw reach in every category; Lemmy wins on trust density in FOSS and self-hosting niches, where a genuine recommendation travels further than any promoted post. They are complements, not substitutes.

vs Mbin (and the late Kbin). Kbin was the other Reddit-alternative that surged in June 2023, but its solo maintainer was overwhelmed and the flagship kbin.social went offline; the project effectively died. Mbin is the community fork that carries the codebase forward, and it federates with Lemmy, so Mbin users participate in Lemmy communities and vice versa.²⁵

vs PieFed. PieFed is a Python-based threadiverse platform by Rimu Atkinson that also federates with Lemmy and adds features like topics and keyword filters. It was a fast riser in early 2026 but remains smaller than Lemmy with a weaker app ecosystem.²⁶ From a publisher's perspective, this is good news: Lemmy, Mbin, and PieFed (plus Mastodon followers) all see the same communities, so one post reaches the whole threadiverse.

vs Discourse. Different category. Discourse is centralized-per-site forum software for running your own community on your own domain; it is not a federated aggregator. If you want to own the space, run Discourse (or a Discord server); if you want to show up where an existing technical audience already is, that is Lemmy.

Put another way: Reddit, Mbin, PieFed, and Lemmy are all reaching for the same job (aggregated link and discussion communities), and three of the four now federate with each other, so a post to the right Lemmy community is effectively visible to Mbin and PieFed users too, plus anyone following that community from Mastodon. Discourse and a private Discord server solve a different job: a space you fully control, with no expectation that strangers from other networks will show up in the thread.

Final word

Lemmy will not appear in your reach reports as a big number, and any tool or consultant telling you otherwise is selling something. Around fifty thousand monthly active people, spread across a few hundred volunteer-run servers, is the whole network.

But those fifty thousand are disproportionately the people who choose the software stacks, write the blog posts, and answer the "what should I use for X" questions that the other billion users search for. For open source projects, developer tools, self-hostable products, and privacy-focused services, a well-written release post in the right community, with the maintainer in the comments, is one of the highest-signal announcements available anywhere. The price of admission is respecting the norms: participate first, promote at the margins, disclose who you are.

Architecturally, Lemmy is also the most faithful "what if Reddit, but nobody owns it" experiment running: ActivityPub federation, documented sorting algorithms, a complete open API, and a funding model that is grants and donations all the way down. Whether that model can grow past its post-exodus plateau is an open question; that it survived losing its second-largest server suggests the design is doing its job.

If Lemmy fits your audience, posterly treats it as a first-class platform: schedule link and text posts to specific communities from the same composer as your Bluesky, Mastodon, and 15 other channels. Start with the Lemmy scheduler, or check pricing if you are weighing plans.