RomM version 4.0.0: A Major Leap for Retro Game Management

This week, Romm announced their groundbreaking new 4.0.0 release, bringing with it a new way of matching metadata with roms, and adding additional metadata services to reduce reliance on Amazon's IGDB service.

RomM itself is a sleek, no-fuss platform for curating, enhancing, and sharing your retro game collection. It’s not an emulator — and it doesn’t try to be one. Instead, RomM works with the tools and platforms you already love, integrating smoothly with apps like Playnite, MoUS, and others that handle launching and emulation.

At its core, RomM is built to help you organise your library, enrich it with beautiful metadata and artwork, browse it from anywhere, and even share it with friends. Whether you’re archiving decades of games or just starting to build a library, RomM gives you full control without locking you into a specific ecosystem.

It’s fully self-hosted, open-source, and lightweight. Designed for both power users and those who just want a clean, plug-and-play experience. Personally, this has been my favorite way to manage retro games. I’ll be honest - self-hosting wasn’t really in my comfort zone before. But since discovering RomM, it’s actually become fun to learn.

And now, with the release of their new version, RomM 4.0.0, the platform has taken a major step forward - with faster scanning, smarter matching, and even mobile access through a brand-new Android app.

The 4.0.0 Update: Smarter, Faster, and Much More Accurate

RomM 4.0.0 isn’t just a version bump, it’s a massive overhaul that touches nearly every part of the platform. And the crown jewel of this release is what is known as "Hash matching".

Before now, RomM relied on filename-based fuzzy matching to scrape metadata for your ROMs — stripping out tags like (Europe) or [v1.1], then trying to match the cleaned-up name to known games through a metadata provider like IGDB. It worked well enough… if your filenames were already accurate.

"Even though we began to get a high success rate," explains RomM team member danblu3, "it relied heavily on your files being named correctly."

Now with hash matching, that entire process changes. RomM 4.0.0 uses your ROM’s unique digital fingerprint (its hash) to identify what game it actually is-regardless of what the file is named.

“You could have a game named TLOZ: AltP.zip — and RomM wouldn’t know what it is, because of the weird name,” says danblu3. “But with hash matching, it looks inside the file, extracts the signature, and instantly matches it. No renaming needed.”

That system is powered by two major backend services: Playmatch and Hasheous, built by Yukine and FlibbleHexEyes, two members of the RomM community. Together, they’ve helped push RomM’s accuracy, reliability, and metadata capabilities to new heights.

What Is Hash Matching, and Why Does It Matter?

Let’s break it down: Every file has a unique “signature”: a cryptographic hash, like a digital fingerprint. Instead of relying on filenames, RomM can now use that hash to determine exactly which game a ROM represents. To do this, it checks that hash against databases created by preservation groups like No-Intro and Redump, who’ve cataloged thousands of ROMs for historical and archival purposes.

“These groups built a digital bible of what game is what signature,” explains danblu3. “With 4.0, we finally introduce hash matching — and it’s so much better.”

Hash matching brings three huge benefits:

• Speed – It’s much faster than fuzzy matching.
• Accuracy – It doesn’t care about file names.
• Flexibility – You can now use compressed formats and still get correct matches.

With hash support now in place, RomM is far less dependent on file names, and instead builds on a much more robust foundation, one that also allows for smarter fallback strategies and hybrid sources.

One of the standout features in RomM 4.0.0 is how much smoother this metadata matching has become. That’s in part due to Hasheous, which works hand-in-hand with RomM (among others).

Although not officially part of the RomM team, FlibblesHexEyes, the developer behind Hasheous, has collaborated closely with the project. Hasheous began as a response to a common pain point: the hassle of getting ROMs matched up with metadata services like IGDB or Screenscraper.

“I noticed a major point of friction for users was matching their ROM files to metadata providers,” FlibblesHexEyes explains. “This led me to start the Hasheous project, where instead of the user having to manually say that file is Choplifter, the client (like RomM) would reach out to Hasheous and say, ‘Do you know what this file with this SHA1 hash is?’”

The idea is beautifully simple: the hash of your ROM is used to identify the game, and Hasheous returns not just the title, but also metadata sources, like summaries, box art, and more. Better still, it handles the messy part many users dread: API keys.

“Many metadata providers require an API key — and an often convoluted method to generate them,” FlibblesHexEyes says. “Hasheous proxies some of those providers, allowing RomM users to have a completely friction-free experience when adding ROMs to their libraries. That’s the part I’m especially proud of.”

The result? With RomM 4.0.0 and Hasheous working together, adding a game to your collection feels nearly automatic: a huge leap in usability for both newcomers and seasoned collectors.

Playmatch and Hasheous: The Backbone of 4.0.0

RomM’s hash system is made possible by two open-source, community-maintained microservices: Playmatch, by Yukine, and Hasheous, by FlibbleHexEyes (also known as the dev behind Gaseous).

“Playmatch was born out of frustration,” says Yukine. “I had a huge ROM collection, and when only ~40% of games got a match through IGDB, I knew there had to be a better way.”

So, in June 2024, Yukine started building Playmatch — a Rust-powered microservice that uses the DAT files from No-Intro and Redump to recognize ROMs based on their hashes. It then maps those hashes to game entries on IGDB and other services.

“The PR to integrate Playmatch into RomM didn’t take long,” he says. “But the service itself took over a year of off-and-on work. It needed to be fast, memory-light, and smart enough to handle complex region-based mappings.”

Playmatch is clever enough to recognise clones and regional variants using the DAT’s internallogic. Like mapping localised versions of Pokémon games back to their parent entries and applying the same metadata. It’s especially effective when paired with compressed ROM formats like .rvz, .wux, and .chd.

“RomM users compress their games to save space,” says Yukine. “But that breaks hash matching unless we account for it — so Playmatch includes support for those community formats too.”

Hasheous, on the other hand, is a separate but complementary service, written by FlibbleHexEyes. It operates on a similar principle and gives RomM a second powerful backend for matching - offering flexibility and resilience in case one service has missing data or fails.

RomM now queries both services as part of its matching workflow, making the entire identification process smarter, faster, and more reliable than ever.

“Without these two amazing devs,” says Danblu3, “4.0 would not be as huge as it is.”

Other New Features in 4.0.0

RomM 4.0.0 isn’t just about hash matching. It includes several other long-requested improvements and quality-of-life updates.

• LaunchBox support – A daily-downloaded offline metadata source that doesn’t rely on API keys or naming conventions. Particularly good at handling ROM hacks.
• RetroAchievements integration – View your progress right from RomM. It shows both hardcore and softcore stats for games with matching hashes. And as far as community-driven projects go, Retro Achievements is by far one of this writer's favorites!
• Official Dev Container – A ready-to-go development environment so new contributors can start hacking on RomM without a painful setup process.

A Community-Powered Ecosystem

RomM 4.0.0 represents more than just a technical update, it’s a showcase of what a passionate community can build together. Developers, testers, and tinkerers are all contributing in different ways: whether it’s Yukine writing Rust services, Flibble running hash databases, or users in Discord submitting manual hash mappings through a bot.

“If a ROM isn't matched, users can now submit a suggestion via Discord,” Yukine explains. “Once approved, that mapping becomes part of the global database — so the next person gets a perfect match.”

This system ensures that metadata matching keeps improving over time — the more people use it, the better it gets.

The Surprise Star: A New Android App

Just when the community thought 4.0.0 was the highlight… along came MattSays.

An independent community member, MattSays developed and released a brand-new Android app for RomM; totally unprompted. It wasn’t planned, commissioned, or requested. It just showed up, fully functional, in the RomM Discord one day.

“MattSays dropped it and the UI was there, the functions were there — everything,” says Danblu3. “It was gorgeous even from a 1.0 release.”

Previously, there was a functional but limited Android app made by another user. But Matt’s version blew expectations away, bringing real usability to Android-based retro handhelds.

“I recently got into Android retro handhelds,” says MattSays. “I discovered RomM but was surprised there wasn’t a proper app to manage my collection. So I made one.”

The result is a slick, controller-friendly app that connects directly to your RomM server, lets you browse your library, and even launch games with just a tap. Completely sidestepping the need to pull SD cards, connect to PCs, or wrangle file shares.

“Imagine this,” says Danblu3. “You open the RomM Android app, scroll with your controller, press A, the game downloads, and you're back in ES-DE playing. No SMB users. No NFS perms. Just done. Dusted.”

The app is now being branded as the official Android connector for RomM, and developers from the main team have already reached out to collaborate with MattSays. His future plans include save syncing, which would open up cross-device play and cloud backup options.

The Future of RomM

RomM 4.0.0 is a game-changer. Not just in the retro front-end space, but in how community-driven open-source projects can evolve through shared frustration, creativity, and just a bit of obsession.

Whether you’re a collector, a preservationist, a self-hosting nerd, or a portable retro gaming fan, there’s something in this release for you.

“This is the biggest release we’ve ever done,” says danblu3. “It’s deserving of the major number. And while there might be a small break after this... we're just getting started.”

I also previously interviewed the developers of RomM, which you can read in full over on Lemmy.