Free PCB autorouter

What it does

Multi-layer, with rip-up and retry

Routes across two to sixteen copper layers. When a net cannot be completed it removes earlier traces and tries a different order rather than giving up on that net and leaving it to you.

Impedance-aware while routing

Controlled-impedance nets are widened or narrowed against the stackup as they are routed, not flagged afterwards. A trace that had to be the wrong width to fit is a trace you would have had to redo.

Via and layer-transition control

Through-hole, blind, buried and microvia rules are enforced per net class, so a two-layer hobby board and a controlled-stackup design do not get the same treatment.

It tells you what it could not route

Every run ends with a connectivity check. If four nets are unrouted you get those four net names, not a completion percentage. An autorouter that reports success while leaving nets open is worse than one that fails loudly.

Is the routing done by AI?

No, and that is deliberate. Routing is a search through physical space against hard constraints — whether this trace clears that pad by 0.15 mm is a measurement, not a judgement. A language model has no way to measure it, so ours does not try.

AI is used earlier, where judgement is the actual task: choosing parts and proposing a circuit. By the time the router runs, everything is geometry and rules. The practical consequence is that routing behaves the same way every time, and does not change when an underlying model is updated.

What autorouters get wrong

Placement matters more than the router

Most unroutable boards are placement problems. If two connectors sit at opposite corners with a dense IC between them, no router recovers that. Ours will report the nets it could not reach so you know what to move.

Dense fine-pitch parts are the hard case

BGAs and fine-pitch packages need escape routing before the general router can help. This is the area we are actively working on, and it is where you are most likely to see unrouted nets today.

Automatic is not always right

Analogue feedback paths, sensitive high-speed pairs and current-carrying power runs are often worth routing by hand. You can route those first, lock them, and autoroute the rest.

Using it

1. Open a board — describe a circuit, import Gerbers, or draw one.
2. Place the parts, or accept the generated placement.
3. Route any critical nets by hand first if you have them.
4. Run Auto-route, then check the design rules and the unrouted list.
5. Export Gerber, drill, pick-and-place and BOM.