Reddit Maps

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Inspiration

Reddit Maps started with a simple idea from Max (u/bookflow): what if Reddit conversations could be visualized on a map instead of buried in endless threads?

As both a map enthusiast and longtime Reddit user, he imagined a faster, more visual way to explore local recommendations, safety tips, events, and hidden gems directly inside subreddits.

Once the idea started gaining traction online, Max brought in Hana (u/HLWriter) and Jona (u/Jonaaldas) to help turn the concept into a real product. The three had worked together before, each bringing different strengths to the table: development, growth hacking, creativity, operations, product development, organization, and user experience — as well as figuring out how three people in/with different locations, schedules, work styles, and life demands could actually build something together.

What Reddit Maps Does

Reddit Maps is a mod tool that transforms subreddit posts and comments into an interactive map displayed directly inside the subreddit.

Mods install the tool, customize filters/settings, and "build" the map using an AI prompt behind the scenes. Based on those settings, the AI scans subreddit conversations, identifies real places being discussed in posts and comments, and pins them geographically on the map which sits at the top of the subreddit. Each pin links directly back to the original Reddit post or comment where the location was mentioned.

Once installed by the mods, Redditors can view the map directly inside the subreddit and explore real community discussions geographically through clickable pins.

Instead of scrolling endlessly through threads, they can visually browse recommendations, local insights, hidden gems, warnings, events, and neighborhood discussions directly from the map itself. (More on this below).

By default, this mod tool enables the map to scan for all location mentions, but moderators can heavily customize what appears.

For example, they can:

• Only show places mentioned multiple times
• Exclude negative recommendations
• Focus only on recent posts
• Surface categories like restaurants, cafés, nightlife, parks, or events
• Separate maps by neighborhood or city (great for subreddits that span multiple geographic locations)
• Create themed maps like “best date spots” or “family-friendly places” (coming soon)

This gives moderators a scalable way to organize local subreddit knowledge without constantly maintaining repetitive recommendation threads.

Why This Matters

Subreddits already contain some of the internet’s best local knowledge. When people want to know where to go, what to do, and where something is going on, where do they go first?

Reddit.

The problem is that the information is fragmented across thousands of comments and subreddits and difficult to visualize.

Reddit Maps makes that information instantly explorable.

Instead of searching through old posts asking:

• “Best tacos in NYC?”
• “Which neighborhoods are safest?”
• “Where should I avoid?”
• “Good cafés in Brooklyn?”

Users can simply open the map and see the community’s knowledge pinned geographically. (We also hope all of this can be eventually synced into Redditmaps.com).

Unlike traditional review platforms, Reddit Maps surfaces real, constantly evolving conversations from communities people already trust.

For moderators, this also helps reduce repetitive posts and creates a more organized, searchable subreddit experience. Instead of answering the same questions repeatedly, communities can surface their collective knowledge visually at the top of the subreddit.

How We Built It

We initially prototyped Reddit Maps using vibe-coding in Claude to validate the concept. After learning the potential value as a moderation tool, we shifted the idea away from a standalone website (for now) and toward something built directly for subreddit communities and their moderators.

We then used Devvit and Reddit’s developer documentation to turn the concept into a fully functional mod tool that could be installed directly into subreddits.

We started in a "sandbox" subreddit which we created to test the idea, pulling restaurant recommendations from r/AskNYC using Reddit’s API and our custom AI prompt.

Early on, we realized that prompting mattered a lot. Since the AI needs to understand subreddit context, recommendations, sentiment, geography, and categories all at once, the prompts became surprisingly detailed. Right now, they’re admittedly longer and more technical than we’d like, but refining and simplifying that moderator experience is part of the long-term product journey.

In this "sandbox" (https://www.reddit.com/r/submaps_dev/comments/1tb89io/rsubmaps_dev_on_a_map/) we tested highly specific prompt conditions including:

• Taco places
• Pizza restaurants
• Bagel spots

And, we were specific on what the actual definition of these were (it is NY, after all!)

This helped us test whether the AI could accurately understand nuanced subreddit context instead of simply tagging anything loosely mentioned throughout the subreddit.

Once that worked, we built a “real-fake” subreddit called r/InternationalAndes to simulate real-world usage with Asian restaurants across Bogotá and Quito, where our team is based. We created posts and commented organically using real places we’ve personally visited, including both positive and negative recommendations, to test filtering, moderation controls, and map accuracy.

One of our test prompts focused specifically on South Asian and East/Southeast Asian restaurants. The AI was instructed to only surface restaurants whose primary cuisine matched a strict approved list while excluding cafés, bakeries, fusion spots, bars, and generic recommendations. It also needed to ignore neighborhood-only mentions and only create pins when a specific eligible venue was clearly named in the conversation. Then, it took the locations mentioned, matched them with GPS coordinates, and was able to map them. (Jona can speak more to the technical side).

This testing process helped us understand how nuanced Reddit conversations can be, and how important moderation controls and prompt customization are for making Reddit Maps genuinely useful across different communities.

Challenges

One of the biggest challenges was figuring out how this should actually function from a moderator’s perspective.

Building the map itself was only part of the problem — the real challenge was creating a workflow that felt intuitive and useful for moderators managing active communities.

We also ran into challenges around how locations and cities are handled behind the scenes. Since maps rely on geographic data, locations essentially need to exist within the system before they can properly render and organize on the map. This became more complicated when dealing with subreddits that mention multiple cities, regions, or less common places. We had to figure out how moderators could dynamically work with locations that may not already exist in the dataset and ensure the AI could still map them correctly.

Another challenge was AI processing costs. While Reddit’s API is free, the AI still needs to process subreddit conversations to extract locations, categorize recommendations, and understand sentiment/context before pins can be placed on the map.

To keep the tool flexible for moderators, communities currently connect their own AI API key. Since processing only happens periodically rather than continuously, costs remain relatively manageable for most communities.

For example, smaller city or recommendation-based subreddits scanning a few hundred posts per refresh would likely only spend a few dollars per month to keep their map updated. Even larger communities can control costs by limiting:

• the number of posts scanned
• recursion depth in comment threads
• update frequency
• specific categories or map layers being generated

Based on our testing, scanning Reddit recursively with ChatGPT 5.5 mini scales relatively linearly. A medium-sized scan averaging deeper recommendation/comment threads works out to approximately:

Posts Scanned Estimated AI Cost 200 posts ~$2.33 300 posts ~$3.50 400 posts ~$4.67

These estimates vary depending on comment depth and subreddit activity, especially in communities where recommendation threads generate large discussion trees. As you can see, while the cost is not that high, we do realize this is a current challenge.

Long term, we plan to offer moderators suggested spending caps and optimization recommendations based on subreddit size, engagement levels, and posting behavior. This is unless, of course, Reddit can help support us in this aspect.

We also hope to eventually simplify the installation experience so moderators can select from just a few dropdown filters, then generate a default prompt automatically, and simply hit “install.” For now, we’ve created a workable solution to help moderators with their prompt while we continue to perfect the mod settings to be more streamlined. For now, it's still 100% usable.

What We Learned

This project pushed us to think beyond a traditional Reddit browsing experience and deeply understand how moderators organize their communities.

We learned:

• How to build directly inside Reddit using Devvit
• How AI can structure messy community conversations into usable data
• How moderation tools need flexibility, simplicity, and control (otherwise, they won’t use them)
• That visual discovery changes how users interact with community knowledge, subreddits, and Reddit as a whole

Most importantly, we realized Reddit Maps could become much larger than a moderation tool alone.

Future of Reddit Maps

Right now, Reddit Maps focuses on turning subreddit conversations into a visual, interactive map experience as a mod tool.

But down the road, we see this becoming much more customizable and scalable for larger communities — and potentially evolving into RedditMaps.com.

As subreddits grow, maps can quickly become crowded, so one of the biggest future opportunities is giving moderators more advanced filtering and organization options behind the scenes.

We envision mods (and, also users) being able to:

• Filter by category
• Filter by sentiment
• Filter by time period
• Filter by post popularity
• Create separate map tabs or layers
• Pin curated “official” community recommendations
• Let users toggle between different map views

For example, a city subreddit could eventually have separate filters for:

• Food
• Nightlife
• Family activities
• Safety tips
• Tourist traps
• Events
• Neighborhood guides

Because the information comes directly from subreddit conversations, Reddit Maps has the potential to surface hyper-local, constantly updated recommendations that feel more authentic and community-driven than traditional review platforms and map websites.

This would turn Reddit Maps from a simple visualization tool into a fully navigable, community-powered discovery layer for Reddit.

We also see strong monetization potential in the future. Restaurants, venues, events, and local businesses already being organically discussed in subreddits could eventually sponsor featured placements or promoted pins while still giving moderators full control over approvals and visibility.

Ultimately, we believe Reddit Maps could evolve beyond individual subreddits into a broader visual way to experience Reddit itself: exploring conversations geographically instead of only through text threads. It might even be Google Maps' next competitor...

Built With

• devvit-reddit-api-for-posts/comments
• devvit-redis-for-storage
• hono
• hono-on-the-devvit-server
• leaflet.js
• openai
• redis
• tailwindcss
• typescript
• vue