Build the truss, then send the truck

Lay road, wood, steel and cable between the anchors on a snapping grid, keep it under budget and press Test: a cartoon truck drives across, every beam glows from green to red under the load, and if the deck gives way the truck lands in the river with a splash and floats.

Play Now

Genre: Bridge building
Controls: Touch
Mouse
Keyboard
Devices: Desktop
Tablet
Mobile
Released: 2026

Did you like Bridge Builder?

Bridge Builder

Bridge Builder is the classic truss bridge game, drawn as a warm cartoon side view. Every challenge is a gap to span, a meadow brook, a river with a sailing boat, a busy harbour, a red canyon at sunset, with red anchor bolts waiting on the banks. Drag from an anchor or a joint to lay a beam: it snaps to the grid, and a ghost shows where it will land, how long it is and what it costs. Road carries the vehicle, wood is cheap but weak, steel is strong but pricey, and cable can only pull. The secret, as every engineer knows, is triangles.

Press Test and the physics runs, a fixed-step simulation that gives the same result on every device. A truck rolls on, later a bus, a tractor towing a trailer of hay bales and two trucks at once. The bridge sags under the weight and every beam glows from green to yellow to red as the stress rises; push one too far and it snaps. If the deck fails, the vehicle drops into the water with a splash and bobs there, nobody hurt, and Back puts your bridge back exactly as it was. Forty brain-teasing challenges grow from a six-square creek to a thirty-square canyon, with stone piers you may lean on, power lines you must stay under and boat channels you must keep clear. Each challenge awards three stars: get across, stay under budget, and keep every beam below 70 percent stress. Every one has been proven solvable within its budget.

Free build is the place to relax: a long valley with no budget, a rocky pier in the middle and two tall towers for cables. Send the truck, the bus, the tractor or two trucks over whatever you dream up, keep up to twenty bridges in your browser and press Photo to save a picture of your favourite. Undo and redo go fifty steps back, the eraser tidies up, and the zoom buttons, the mouse wheel or a pinch get you close to the joints. Keys 1 to 3 pick wood, steel and cable, 4 picks road, Space tests, Z and Y undo and redo, P pauses and M mutes.

Tips for Bridge Builder

Bridge Builder rewards triangles. A single beam bends, but three beams joined in a triangle hold their shape, so build your truss from triangles above or below the road and the load spreads across many beams instead of a few. Lay the road first, then add the support. Use cheap wood where the stress stays low and save steel for the beams that glow red when you test. Cable can only pull, so use it to hang the deck from something higher, never to push it up.

Press Test early and often. The colours show exactly where the bridge is weak: green is comfortable, yellow is working hard and red is close to snapping. Back puts the bridge back exactly as it was, so a failed test costs you nothing, and because the physics gives the same result every time, a fix that works once keeps working. Go for crossing first, then trim the cost for the budget star, and finally strengthen the busiest beams to keep every one below 70 percent stress for the third. Where a challenge has stone piers, lean on them.

Frequently asked questions

Is Bridge Builder free to play?

Yes. Bridge Builder is free to play in your browser on Kiloo, with nothing to download and no account to create. In free build you can keep up to twenty bridges in your browser and press Photo to save a picture of your favourite.

Can I play Bridge Builder on my phone?

Yes. On a phone or tablet you drag from a joint with a finger to lay a beam, and pinch or use the plus and minus buttons to zoom. On a computer, keys 1 to 3 pick wood, steel and cable, 4 picks road and Space tests.

How do I get three stars in Bridge Builder?

Each challenge has three stars: get the vehicle across, stay under the budget and keep every beam below 70 percent stress. All forty challenges have been proven solvable within their budgets, so the budget star is always within reach.

What happens when the bridge breaks?

If a beam is pushed too far it snaps, and if the deck fails the vehicle drops into the water with a splash and floats there, with nobody hurt. Press Back and your bridge returns exactly as it was, ready to fix and test again.