Inside 2XKO’s Technology: How Riot Built Its Next-Gen Fighting Game

2XKO may look like a stylish, fast-paced fighting game set in the League of Legends universe, but some of its most interesting features are happening where players can’t see them.

Behind every combo, tag, parry, online match, and last-second comeback is a surprisingly sophisticated collection of networking and server technologies.

And Riot Games isn’t simply trying to make another fighting game with good netcode.

2XKO has been designed around online play from the beginning, with technologies including rollback netcode, a client-server architecture, Riot’s global network infrastructure, server-side game validation, fixed input delay, advanced frame pacing, and Riot Vanguard anti-cheat.

That’s particularly important because 2XKO introduces another complication that most traditional fighting games don’t have to deal with: four-player matches.

So how does all of this actually work?

Here’s a closer look at the technology behind 2XKO and why it could be one of the game’s biggest advantages.

2XKO Was Designed for Online Play From the Start

One of the most interesting things about 2XKO’s development is that online play wasn’t treated as something to figure out near the end.

It was part of the foundation.

Riot says one of its first priorities when developing the game’s core technology was integrating GGPO, the rollback networking technology closely associated with modern fighting games.

The developers then moved their internal playtests online.

Even when early versions of 2XKO were still using peer-to-peer networking, Riot ran those matches through a packet proxy in its Las Vegas data center.

In other words, developers weren’t testing characters under perfect local conditions and hoping everything would eventually work online.

Characters, attacks, animations, mix-ups, and visual effects were being tested under real internet conditions.

That distinction matters.

Fighting games are extremely sensitive to latency. A delay that would barely be noticeable in an RPG can completely change the outcome of a fighting game match.

If an attack takes only a few frames to start, even tiny differences in input latency can affect reactions, combos, blocks, and punishes.

For 2XKO, networking isn’t simply infrastructure.

It’s part of the gameplay design.

Rollback Netcode Is at the Heart of 2XKO

If you’ve followed fighting games over the past few years, you’ve probably heard the term rollback netcode.

The basic idea is surprisingly clever.

Instead of waiting for every player’s input before advancing the game, rollback systems predict what a remote player is going to do.

If the prediction is correct, everything continues normally.

If the prediction is wrong, the game quickly corrects — or “rolls back” — the game state and resimulates what should have happened.

Ideally, the correction happens so quickly that the player barely notices it.

This is generally much better suited to fighting games than traditional delay-based networking, where the game may pause or increase input delay while waiting for information from another player.

But 2XKO makes the problem more complicated.

A traditional fighting game normally has two players.

2XKO can have four.

That means the networking system potentially needs to synchronize inputs and game states between twice as many people.

And that’s one reason Riot eventually moved beyond a traditional peer-to-peer architecture.

Why 2XKO Uses Client-Server Architecture

One of the most unusual technological decisions behind 2XKO is its move from peer-to-peer networking to a client-server architecture.

In many fighting games, the two players communicate more directly with each other.

2XKO instead uses a central game server.

Why?

Four-player matches are part of the answer.

With multiple players connected to the same match, keeping everyone’s simulation synchronized becomes considerably more complicated.

Riot describes one important challenge as balancing the “rift.”

In simple terms, players shouldn’t experience wildly different rollback conditions.

If one player is constantly experiencing large corrections while another player barely experiences any, the match isn’t really providing an equal competitive environment.

The server therefore acts as an authority for time.

It helps synchronize the game clocks of the players and distribute the effects of rollback more consistently.

That gives Riot much more control over the online experience than a conventional peer-to-peer setup.

And there’s another major advantage.

One player’s bad connection doesn’t necessarily have to ruin the match for everyone else.

That’s where another interesting piece of 2XKO technology enters the picture.

Fair Play Mode Could Change How Fighting Games Handle Lag

Anyone who plays fighting games online knows the experience.

You find an opponent.

The match begins.

Then suddenly everything starts stuttering.

Maybe they’re playing on unstable Wi-Fi. Maybe their PC is struggling. Maybe they’re experiencing packet loss.

Or, in extreme cases, someone could intentionally manipulate their connection.

Traditional peer-to-peer networking has limited options when this happens because the game needs information from both players.

2XKO’s experimental Fair Play mode takes a different approach.

The server gives player inputs a short period of time to arrive.

If an input arrives too late, instead of making everyone wait, the server can replicate that player’s previous input and continue the match.

The player with the unstable connection suffers the consequences rather than forcing the other players to share the same disruption.

It’s an aggressive solution.

And Riot acknowledges there’s a trade-off.

If your own internet connection suddenly drops packets, your character may continue performing an old input while your opponent continues playing normally.

You could reconnect only to discover that you’re already being hit by a combo.

But competitively, the philosophy makes sense:

Your opponent’s connection shouldn’t become your problem.

Fair Play is still an experimental technology that Riot has been tuning, but it could become one of 2XKO’s most interesting contributions to online fighting games.

Riot Direct Gives 2XKO a Serious Infrastructure Advantage

2XKO also benefits from something most fighting game developers simply don’t have:

Riot Games’ enormous global networking infrastructure.

Instead of relying entirely on the normal routes internet service providers choose for traffic, 2XKO can use the Riot Direct backbone.

Riot has spent years building this infrastructure for games such as League of Legends and VALORANT.

For 2XKO, game traffic can travel through Riot’s network toward strategically deployed game servers.

The objective is straightforward: reduce unnecessary routing and provide more predictable latency.

Riot is also using its infrastructure to deploy servers around the world, with the long-term goal of having servers relatively close to players across supported regions.

The servers are additionally protected against DDoS attacks.

That’s particularly relevant for competitive gaming.

If Riot wants 2XKO to become a serious esports title, network reliability isn’t just important for ranked matchmaking.

It’s critical for tournaments.

Every Match Can Be Validated in the Cloud

Here’s where things get even more interesting.

2XKO uses something Riot calls the Game Validation Server, or GVS.

Essentially, Riot can run a validated copy of a match in the cloud.

That server-side simulation opens the door to several features.

It can help with anti-cheat.

It can help validate competitive results.

It can contribute to skill-rating systems.

And it can power spectating.

Fighting games using rollback networking are deterministic. If the game knows the starting state and receives the same sequence of player inputs, it can reproduce what happened.

That makes server-side match reconstruction extremely useful.

Instead of treating spectators as ordinary players connected to the match, Riot can use validated game information to create a more sophisticated spectating system.

This matters beyond casual viewing.

Reliable server-side spectating could eventually become extremely valuable for tournaments, broadcasts, replay systems, coaching, and competitive analysis.

Riot Vanguard Protects Competitive Matches

Fast networking doesn’t matter much if competitive matches are filled with scripts and bots.

That’s why 2XKO uses Riot Vanguard.

Vanguard is Riot’s proprietary anti-cheat system, already used elsewhere in the company’s competitive ecosystem.

In a fighting game, cheating can look very different from cheating in a shooter.

Imagine a script capable of automatically parrying attacks.

Or software detecting whiffs and immediately triggering the perfect punish.

At high levels of play, reactions happen within extremely small windows. Automated input systems could therefore create an enormous competitive advantage.

Vanguard is designed to make those kinds of tools significantly harder to use.

For Riot, anti-cheat and networking are therefore parts of the same bigger objective:

creating an online match players can trust.

Why 2XKO Uses a Fixed Three-Frame Input Delay

Rollback isn’t the only technique Riot uses to make matches feel consistent.

2XKO deliberately applies a fixed three-frame input delay.

And importantly, that delay isn’t limited to online matches.

It’s also used offline.

At first, deliberately adding latency might sound like a bad idea.

But there’s a good reason.

A small fixed delay gives rollback networking some breathing room while keeping the player’s experience predictable.

More importantly, applying the same delay online and offline means players don’t need completely different muscle memory depending on where they’re playing.

A combo practiced offline should feel similar online.

A punish learned in training mode shouldn’t suddenly require different timing in ranked play.

Riot says the game’s combat timings were built around this three-frame input delay.

So it isn’t a networking patch added afterward.

It’s baked into the combat system itself.

Frame Pacing Matters Just as Much as Ping

Players usually talk about ping when discussing fighting game performance.

But latency is only part of the story.

Frame pacing is equally important.

A game can technically run at the correct frame rate while still feeling inconsistent if individual frames aren’t delivered at regular intervals.

That inconsistency can cause visible stutter and, more importantly for fighting games, make precise inputs feel unreliable.

2XKO therefore puts significant emphasis on making frame simulation, rendering, and display timing consistent.

Riot has also worked to minimize latency differences between platforms.

The goal is for an input on PC, PlayStation 5, or Xbox Series X|S to produce a visual response in roughly the same amount of time.

That’s particularly important because 2XKO supports cross-platform play.

If one platform had substantially lower input latency than another, competitive cross-play could create an inherent advantage.

Keeping the platforms closely aligned makes cross-platform competition much more viable.

Four-Player Fighting Changes the Technical Challenge

The duo system is arguably what makes 2XKO’s technology especially interesting.

This isn’t simply a tag fighter where one person controls two characters.

Two people can form a team.

That means a full match can involve four human players.

And Riot has continued expanding the technology surrounding that idea.

In 2026, the game added features designed specifically around duo play, including improved duo matchmaking and in-game voice chat.

There’s even a Teamfight Fuse that temporarily allows both champions on a team to fight simultaneously.

These mechanics create situations that conventional fighting game engines and networking systems don’t normally need to handle.

Suddenly the game has to coordinate multiple players, characters, inputs, effects, assists, and online connections while maintaining the deterministic simulation required for rollback.

That’s a much more difficult networking problem than simply connecting two players.

2XKO Is Still Evolving in 2026

Another reason the technology behind 2XKO is worth watching is that Riot continues to modify the game.

Throughout 2026, patches have introduced new champions, gameplay adjustments, bug fixes, duo features, voice chat, and even additional modes.

The June 2026 update, for example, was described by Riot as its largest update at the time, adding Senna, Thresh, and the PvE mode The Climb.

Updates have also addressed console stability and other technical issues.

That’s important context.

2XKO’s technology isn’t a finished system sitting underneath a static fighting game.

It’s infrastructure supporting a live-service competitive game that Riot expects to evolve over time.

New characters can change gameplay complexity.

New modes can create different server requirements.

Competitive features can increase demand for spectating and validation.

And new regions require additional infrastructure.

The technology has to evolve alongside the game.

Could 2XKO’s Technology Influence Future Fighting Games?

Rollback netcode itself isn’t new.

GGPO helped popularize the concept years ago, and rollback has increasingly become an expectation rather than a luxury for modern fighting games.

But 2XKO’s implementation is interesting because Riot is combining several technologies into one ecosystem:

rollback networking, centralized game servers, global routing infrastructure, server-side validation, anti-cheat, fixed input latency, cross-platform frame pacing, and systems designed specifically for four-player matches.

Individually, none of these concepts completely reinvents online gaming.

Together, though, they represent a much more infrastructure-heavy approach to the fighting game genre.

And Riot has the resources to operate that infrastructure globally.

If the system works well at scale, other fighting game developers will almost certainly be paying attention.

Players may start expecting more than simply “good rollback.”

They may expect better protection against unstable opponents, more sophisticated spectating, stronger anti-cheat, consistent cross-platform latency, and server infrastructure built specifically for competitive play.

The Technology Behind 2XKO May Be Its Biggest Competitive Advantage

It’s easy to focus on 2XKO’s flashy side.

The League of Legends champions.

The huge combos.

The tag mechanics.

The visual effects.

The competitive tournaments.

But underneath all of that is a remarkably ambitious technical foundation.

Riot isn’t simply using rollback netcode and calling it a day.

2XKO combines rollback with client-server networking, Riot Direct infrastructure, Game Validation Servers, Vanguard anti-cheat, fixed input delay, careful frame pacing, cross-platform optimization, and experimental technologies such as Fair Play mode.

And perhaps the most important detail is that these systems weren’t designed after the fighting game was finished.

Online play influenced how 2XKO was built from the beginning.

That could ultimately be one of the game’s greatest strengths.

Because in a modern fighting game, the technology you don’t see can matter just as much as the characters fighting on the screen.