Back to all posts
Open Source
Aug 12, 2025
8 min read

The Future of Open Source Moderation

How open source moderation tools are democratizing content moderation and creating more equitable online spaces.

What does it mean to moderate a global conversation? Not the sanitized corporate version of that question, but the real, messy one: How do you build systems that work for a teenager in Tokyo, a political activist in Nairobi, and a hobbyist forum in rural Iowa, all at the same time?

We've been thinking about this problem a lot, and we're increasingly convinced that the answer isn't a better algorithm at a bigger company. It's something more fundamental: giving communities the tools to moderate themselves.

The Problem with Centralized Moderation

Let's start with what's broken.

The dominant model of content moderation today is centralized: a handful of very large platforms make decisions for billions of users. These platforms employ thousands of moderators, build sophisticated ML systems, and publish lengthy community guidelines. And yet, moderation remains one of the most contentious aspects of our digital lives.

Why? Because one-size-fits-all moderation fails across countries, cultures, and communities. What's considered acceptable humor in one culture is deeply offensive in another. What's political speech in one context is incitement in another. A gaming community has vastly different norms than a professional networking group.

Corporate moderation simply can't scale to accommodate this diversity. Not because these companies lack resources (they have plenty) but because the problem is structurally unsolvable at that level of abstraction. You can't write a single rulebook that works for everyone on Earth.

And then there's the opacity problem. When a platform removes your content or suspends your account, you're often left guessing why. Appeal processes feel like shouting into a void. Even when platforms publish their guidelines, the actual decision-making process remains a black box. This opacity breeds distrust, and that distrust is corrosive to the entire system.

Bluesky's Stackable Approach

So if centralized moderation doesn't work, what does?

Bluesky has been pioneering an approach they call "stackable moderation," and we think it's pointing in the right direction. The core insight is simple but powerful: instead of one moderation system for everyone, what if users could choose which moderation systems to apply to their experience?

The technical implementation is through Ozone, their open-source collaborative moderation tool. With Ozone, teams can collaboratively review reports, create labels, and inspect content. But here's the crucial part: these labels don't automatically result in removal. Instead, they're metadata that users and clients can choose how to handle.

Think of it like this: one moderation team might label certain content as "adult content," another might label things as "unverified claims," and a third might focus on "spam." As a user, you decide which of these labels you want to act on and how. Maybe you want adult content hidden but unverified claims merely flagged. That's your choice.

This is a fundamental shift from "platform decides what you see" to "communities create spaces with their own norms and preferences." It's not a free-for-all. There are still baseline safety requirements. But it recognizes that beyond those baselines, different communities legitimately want different things.

The model also changes the economics. Instead of one company bearing the entire burden of moderation for billions of users, the work distributes across many specialized teams who understand their communities deeply.

Specialized Open Source Tools

The Bluesky model only works if the underlying tools are accessible. And that's exactly what's happening across the ecosystem: specialized open-source tools are emerging to address specific moderation challenges.

Take Altitude, a free tool developed by Tech Against Terrorism specifically for identifying terrorist and violent extremist content. This is exactly the kind of specialized expertise that small platforms can't develop on their own. A twenty-person team running a niche forum shouldn't need to become experts in recognizing ISIS propaganda. They can leverage tools built by people who are.

For more general content analysis, projects like content-checker offer AI-powered detection capabilities with analysis of malicious intent. These aren't just simple keyword blockers; they understand context, they detect attempts at circumvention, and they can distinguish between, say, a discussion about violence in historical context and an actual threat.

There's also a growing ecosystem around what people are calling "guardrails for AI applications." As more products integrate language models, there's a need for open-source firewalls that can sit between the model and the user, catching harmful outputs before they reach anyone. These tools aren't perfect, but they're getting better rapidly, and their open-source nature means improvements benefit everyone.

What's exciting about this proliferation isn't just the individual tools. It's the composability. A community can stack multiple specialized tools together: Altitude for extremist content, a custom classifier for their community's specific concerns, and a spam filter trained on their historical data. The modular approach means communities can build exactly the system they need.

AI-Assisted Moderation

We need to talk about the role of AI in all this, because it's both the most promising and most misunderstood part of the equation.

The promise is real. OpenAI offers a free Moderation endpoint that gives solo developers and small nonprofits alike access to the same safety classification capabilities that power massive platforms. This democratization matters enormously. Five years ago, building content moderation into your application meant either accepting spam and abuse or paying for expensive third-party services. Now it's an API call.

Modern language models are particularly good at something that used to be nearly impossible: detecting circumvention attempts. Users trying to evade filters are creative: they use homoglyphs, intentional misspellings, coded language. Traditional keyword-based systems can't keep up. But LLMs understand meaning, not just patterns, which means they can identify malicious variations even when they've never seen that specific formulation before.

But here's where we need to be honest about the limitations. AI moderation isn't magic, and treating it as such leads to real harms.

False positives matter enormously in moderation. When an AI incorrectly flags legitimate content, it's not just an inconvenience. It can silence important speech, harm vulnerable communities, and destroy trust in the system. Marginalized groups often find their speech disproportionately flagged because the training data reflects existing biases.

This is why the most effective systems use human-AI collaboration rather than pure automation. AI does the initial triage at scale, surfacing content that needs attention. Humans make the final calls on ambiguous cases. The AI handles the 90% that's clearly fine or clearly problematic; humans focus on the 10% that requires judgment.

This hybrid approach lets small teams punch above their weight. A community with two part-time moderators can effectively moderate a space that would otherwise require twenty, because the AI filters out the obvious cases and prioritizes what needs human attention.

Democratization in Practice

Let's make this concrete. What does it actually look like when small platforms and communities gain access to these tools?

Imagine you're running a forum for people recovering from addiction. Your moderation needs are specific: you need to catch spam like everyone else, but you also need to identify potential self-harm content, detect people trying to sell substances, and maintain the supportive tone that makes your community work.

A few years ago, your options were limited. You could try to do everything manually, which doesn't scale. You could use off-the-shelf tools that weren't built for your context. Or you could just accept that bad actors would find their way in.

Today? You can use OpenAI's moderation API as a baseline filter. You can add a custom classifier trained on your community's historical moderation decisions. You can implement Bluesky-style labels so your experienced members can flag concerning content for review. You can use open-source tools specifically designed for detecting substance-related content.

None of these tools are perfect. But together, they give a small community capabilities that were previously only available to platforms with massive resources.

And crucially, you control it. You can see how the algorithms work. You can adjust the thresholds. You can add new labels when your community identifies a need. The opacity that makes corporate moderation so frustrating simply doesn't exist when you're running open-source tools on your own infrastructure.

This transparency builds trust in ways that no amount of corporate communication can. When members ask "why was this removed?", you can actually show them. When they disagree with a decision, you can have a real conversation about the tradeoffs. The moderation system becomes something the community owns rather than something that's done to them.

Challenges Ahead

We'd be doing you a disservice if we painted this as a solved problem. It isn't. Open-source moderation faces real challenges that we need to address honestly.

Coordination across federated systems. When communities can create their own moderation rules, what happens when content crosses community boundaries? A post that's perfectly acceptable in one community might violate another's norms. The technical infrastructure for handling this gracefully is still immature. We need better standards for how moderation metadata propagates, how communities can share block lists, and how users can maintain consistent experiences across different spaces.

Maintaining quality as tools proliferate. More tools doesn't automatically mean better moderation. Some open-source projects are well-maintained and trustworthy; others are abandonware with security vulnerabilities. As communities increasingly depend on these tools, we need better ways to evaluate quality, fund maintenance, and ensure responsible development practices.

Balancing openness with abuse prevention. Here's a genuine tension: the same openness that lets communities customize their moderation also lets bad actors understand exactly how to evade it. If your spam filter's code is public, spammers can optimize against it. If your harassment detection rules are transparent, harassers can find the edge cases. There's no perfect answer here. It's a tradeoff between accountability and security that each community needs to navigate.

Resource imbalances remain. Open-source tools lower the barrier, but they don't eliminate it. Running sophisticated moderation still requires technical expertise, computing resources, and human time. The gap between what a well-resourced community can do and what a small volunteer effort can manage is narrower than before, but it's still real.

Legal and liability questions. Who's responsible when an open-source moderation tool fails? If a community uses a third-party labeling service and that service makes a mistake, what are the implications? The legal frameworks around federated moderation are still developing.

Where This Is Going

Despite these challenges, we're optimistic about where this is heading.

The fundamental shift from platform-imposed moderation to community-controlled infrastructure feels like progress. It acknowledges the genuine diversity of human communities. It puts power closer to the people affected by decisions.

The technical pieces are falling into place. Open-source tools are maturing. APIs are becoming accessible. Standards for interoperability are emerging. AI capabilities are improving while becoming more widely available.

What's needed now is coordination: bringing together the people building these tools, the communities using them, and the researchers studying their effects. We need shared infrastructure, common standards, and honest conversations about what's working and what isn't.

Content moderation will never be a solved problem. There will always be bad actors adapting to new defenses, edge cases that require human judgment, and legitimate disagreements about where lines should be drawn. But that's okay. The goal isn't perfection. It's building systems that are transparent, accountable, adaptable, and fair.

Open-source moderation won't be perfect either. But it might be the most honest approach we've tried: acknowledging that different communities need different things, providing the tools to build those things, and trusting people to participate in the systems that govern their digital lives.

That feels like the right direction.

Sources & References6