OpenFront Buildings — Categories, Prices and Upgrades

OpenFront buildings are the interface between gold and power: every city, port, factory, defence post and missile in the game is bought from one build menu and placed on tiles. Because prices scale with how many you already own, and because a few structures unlock others, the order you buy them in matters as much as the amounts. This page covers the four categories, the placement and upgrade rules, and the full gold cost of every structure.

What Counts as a Building

The buildable list is small and stable. Economic structures are cities, factories and ports; military structures are defence posts, missile silos and SAM launchers; warships are the one ship bought from the menu; and the missiles, atom bombs, hydrogen bombs and MIRVs, are fired from a silo rather than placed directly. Two more units never appear in the menu: transport ships, created by attacking across water, and trade ships, which spawn automatically from ports. You can open the menu by right-clicking (or long-pressing on mobile) a tile, or by using the number-key shortcuts shown on the controls page.

Placement and Upgrade Rules

Structures take a few seconds to construct, with a progress bar, unless the lobby has Instant Build enabled, and they must be at least 15 tiles apart according to the current community wiki. Some have extra rules: ports need a coastal tile, warships launch onto water, and missiles need a silo in range. Most structures can be upgraded by building the same structure on top of an existing one, which raises its level and makes it more effective, whether that means a larger troop cap, a wider SAM radius or more silo ammunition. Upgrade levels also make you look like a juicier target to the AI nations.

Structure	1st	2nd	3rd	4th	Later	Upgradable
City	125,000	250,000	500,000	1,000,000	1,000,000	Yes
Factory	125,000	250,000	500,000	1,000,000	1,000,000	Yes
Port	125,000	250,000	500,000	1,000,000	1,000,000	Yes
Defense Post	50,000	100,000	150,000	200,000	250,000	No
Missile Silo	1,000,000	1,000,000	1,000,000	1,000,000	1,000,000	Yes
SAM Launcher	1,500,000	3,000,000	3,000,000	3,000,000	3,000,000	Yes
Warship	250,000	500,000	750,000	1,000,000	1,000,000	No

Ports and factories share one ladder, so the second structure of either kind already costs 250,000. If a lobby enables Infinite Gold, every structure is free for human players in single player and private matches.

Economic Structures

Cities are the backbone: they raise maximum population, which is the ceiling your army grows into, and the current community wiki puts the increase at 250,000 per level while the older wiki recorded a much smaller figure. Treat the exact number as patch-sensitive. Ports must sit on a coast, spawn trade ships that pay both ends of the route and are required before any warship can be built. Factories are the inland answer, linking cities and ports by rail and spawning trains that pay every station they pass. None of the three is glamorous alone, but together they fund everything else.

• City: raises the army ceiling; buy early and often.
• Port: coastal only; income plus the warship unlock.
• Factory: inland income; strongest where several neighbours will connect.
• Shared ladder: alternating port and factory purchases gets expensive fast, so pick a lane early.

Military, Ships and Missiles

Defence posts are the cheapest border upgrade and the only non-upgradable structure. Missile silos gate the entire nuclear tree and cost a flat million each. SAM launchers shoot down incoming warheads, with the current wiki describing roughly nine-second interceptions and a radius that grows with level. Warships launch from a port, patrol, and capture enemy trade ships as well as sinking transport ships and other warships; the current wiki gives them 1,000 HP and 250-damage shells with veterancy over their service life.

Missile	Cost	Note
Atom Bomb	750,000	Small blast, good against clustered structures
Hydrogen Bomb	5,000,000	Large blast that destroys everything in the area
MIRV	25,000,000 plus 15,000,000 per earlier MIRV	Splits into many warheads across a target's whole territory

• Silo first: no silo, no missile, and each launch puts it on cooldown.
• SAM before silo: a silo without interception invites a counter-strike you cannot answer.
• Spread the cluster: one hydrogen bomb can erase a tight group of cities or ports.
• Level matters: upgraded structures are stronger and more tempting, so defend the ones you level.