Host Migration
Host migration is the handover of host duties to another player when the current host of a peer-to-peer match disconnects. Done well, the match pauses briefly and continues. Done badly, or not at all, everyone loses the session. It is one of the failure modes dedicated servers exist to avoid.
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Why Does Host Migration Keep Happening?
In many multiplayer games, one player's game acts as the server, a listen server, and everyone else connects to it, often through a relay. That player is the host. Their machine holds the game state, decides what happens, and carries every other player's connection.
"If the player who is hosting the game exits, everyone gets disconnected. It's a fundamental issue you need to figure out because it literally kills the game session end to end."
Michal Buras, Highwire Games, Live Service Game Summit, September 2024
Host migration exists to save the match when that happens, and it happens often, because the host is an ordinary player. Hosts quit, crash, lose their Wi-Fi or put the console to sleep, and many do not know they were hosting. On Six Days in Fallujah, Buras saw players "randomly quitting the game because our game is a difficult game," and "maybe they are not aware about being a host." The harder the game and the more strangers in the match, the more often a host is likely to leave.
Relays do not change this. They hide IP addresses and help connections through NAT, but the host is still a player, which Buras called "a fundamental challenge" of every relay option he evaluated.
What Has to Move When the Host Leaves?
A migration has three jobs to finish, with the old host already gone:
Choose a new host, usually the remaining player with the best connection.
Rebuild the match on that machine. The new host needs a complete, current copy of the game state. Enemy AI, physics and rewards often exist only on the host, so a game has to keep copies on other players' machines ahead of time.
Reconnect everyone to the new host, through connection setup again.
When a step fails, players report the symptom rather than the step:
What players report | The step that failed |
|---|---|
Stuck on "host migration in progress" | Reconnecting to the new host |
Lost loot or progress | Rebuilding state that existed only on the old host |
Sent back to the menu or hub | The migration as a whole |
Warframe shows the second row plainly. Its official wiki notes that resources, mods and affinity picked up during a mission "will be lost upon a failed host migration since these rewards are determined client-side" (Warframe wiki).
What Does It Cost to Build Host Migration?
Keeping a copy of the match ready on every machine that might become host touches nearly every system in a game. Buras added basic host migration to Six Days in Fallujah with Unreal Engine's net driver:
"The whole project required full refactor in order for all the features to support it. Now, each small feature, each designer made blueprint had to be reworked."
Engines and libraries can help, with a cost he also named: there is "no silver bullet for implementing host migration, unless your engine natively supports it, but this will come with a network bandwidth cost." The state every potential host needs has to keep flowing to them.
The bill is ongoing, since every new feature has to survive a migration and be tested for it. Highwire's estimate was one additional developer and one tester, "around 15K dollars" a month, "and that will just grow later" (Live Service Game Summit talk, September 2024).
"Either you hire additional staff or you move your project release date. In both cases, you burn money."
How Do You Avoid Host Migration Entirely?
Take the host off players' machines. A server does not rage-quit, sleep or lose its Wi-Fi, so there is nothing to migrate. Buras reached the same point from the relay side: once a relay runs game logic, "it's not a relay server anymore. It becomes a form of a dedicated server."
That leaves two shapes:
A full dedicated server runs the authoritative simulation for each match. It is the strongest option for fairness and cheat resistance, and the most work for a game built host-client.
A relay-like dedicated server is a small server, or a multi-room one running many matches in one process, that takes over the host's role with minimal resources: close to a relay's cost, with a dedicated server's performance, coverage and security. For a host-client game it is often the shorter path, since the host's logic can usually run as a headless build.
Bloody Bastards, a mobile game, moved from host-trusted peer-to-peer to headless authoritative servers, with "fractional vCPU sizing" letting it run "smaller, right-sized dedicated servers" (case study, Tibith Ltd, 2026).
A word from our sponsor (ourselves!)
Most lag comes from distance, not from code. Edgegap's Edge Cloud is a distributed network with up to 615+ locations available on demand, so each match runs at the best available location for its players. Independent replays of live studio traffic measured a 58% drop in average round-trip time compared with public cloud.
Edgegap's Take (just our opinion, take it with a grain of salt!)
Pay for Stability, Not for Migration
Host migration rescues a match from a problem the architecture created: a player's machine holding the session. Money spent on it keeps that problem in the game.
Buras put it at around $15,000 a month in staff, and rising. At Edge Cloud's list price of $0.00115 per vCPU per minute (platform data, 18 September 2026), that is roughly the compute for 217,000 thirty-minute matches on a 2 vCPU server, before egress. A relay-like server on a fraction of a vCPU, or running many matches per process, stretches it further.
So we start from the player: every match on a dedicated server, full or relay-like, sized to what the host actually did. To estimate it for your game, use the pricing calculator with its real match length, players and resources.
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