Which PCB Autorouter Should You Use? Traditional and AI Options Compared
An autorouter draws the copper for the connections your schematic defines. Traditional routers search for paths, and when they get stuck they rip up earlier tracks and retry. AI routers add a learned model that proposes and scores many candidate layouts. Neither fixes poor placement or wrong rules, and neither replaces your review. Below are the real options in October 2026, what each costs, and where each fits. ProtoFlow is our product, and it is marked as such.
Last reviewed: 2026-10-19 · By ProtoFlow Engineering Team
Quick answer
There is no single best PCB autorouter. Pick by the tool your board lives in and how much of the layout you want automated: Freerouting is the free open-source router for any tool that exports Specctra DSN, Altium Designer, Autodesk Fusion and EasyEDA have routers built in, and Quilter and DeepPCB are cloud AI services that work on a board you upload. Whichever you use, route the critical nets by hand first and check the result with DRC in the tool you will build from.
PCB autorouters compared (checked October 19, 2026)
Autorouter
Approach
Where it runs
Works with
Cost
Freerouting 2.5.0
Traditional, open source
Desktop app (Windows, macOS, Linux), CLI, beta web API
Any tool with Specctra DSN export, including KiCad, Fusion and EasyEDA
Free (GPL-3.0)
KiCad 10 router
Interactive router; finishes selected tracks one at a time, no full-board autoroute
Inside KiCad
KiCad; exports DSN for external routers
Free (GPL-3.0 or later)
Altium Designer Situs
Traditional, topological mapping
Inside Altium Designer
Altium projects
Paid annual subscription
Autodesk Fusion Autorouter
Traditional rip-up and retry, plus the gridless TopRouter
Inside Fusion Electronics
Fusion electronics designs
Part of Fusion (plans on Autodesk's site)
EasyEDA Pro Auto Routing
Traditional (JRouter or HRouter engine)
Inside EasyEDA Pro
EasyEDA projects; DSN export for Freerouting
Free plan, commercial use allowed
Quilter
AI placement and routing (reinforcement learning, physics checks)
Cloud; self-hosted option
Returns Altium, Cadence Allegro, Siemens Xpedition or KiCad files
Free tier for teams under 10 people and $50K revenue; otherwise per project, priced by pins to route
DeepPCB (InstaDeep)
AI routing (reinforcement learning) of a placed board
Cloud web app; KiCad plugin
Altium, KiCad, EasyEDA, Zuken, OrCAD, Allegro, Eagle, or any Specctra DSN
One 30-minute trial board, then prepaid hours from $30 for 1 hour
ProtoFlow (our product)
Built-in auto-router, plus an AI agent (Studio) that can place and route
Prices and Plan Limits, Checked Against Vendor Pages
Each row links to the vendor page it came from and shows the date we last read that page. Vendors change pricing often, so check the link before you buy.
Product
Price or limit
Source
Checked
Freerouting
Free, open source (GPL-3.0); v2.5.0 released October 5, 2026
An autorouter turns ratsnest lines into tracks and vias. It works from the netlist, the placed footprints, the board outline and your design rules: track widths, clearances, via sizes and net classes. It does not decide what the circuit is or where the parts go, unless it also does placement.
Placement decides most of the result. Altium's own Situs documentation says that if part of a board cannot be routed by hand, it will not be autorouted either. Autodesk's Fusion help gives the advice most engineers give: route critical signals by hand first, then let the autorouter do the rest.
So the useful question is not which autorouter is best in general. It is which one fits the tool your board already lives in, how dense the board is, whether you can upload it to a cloud service, and how much cleanup you will accept.
Traditional autorouters: Freerouting, Altium, Fusion and EasyEDA
Freerouting is the free baseline. Version 2.5.0 shipped on October 5, 2026. It is GPL-3.0, has installers for Windows, Linux and macOS, and also runs from the command line, through a beta web API, or as an MCP server for AI assistants. You export a Specctra DSN file from your CAD tool, route it, and import the SES session file back. Its README says a run can take from a few minutes to several hours.
Altium Designer's Situs router maps the board topologically before it lays down tracks, and it obeys the electrical and routing rules except Routing Corners. Altium's documentation says differential pairs must be routed and locked by hand before you run it. Altium also has ActiveRoute, a guided router for selected groups of nets.
Autodesk Fusion's autorouter uses rip-up and retry and leaves your hand-routed tracks alone. Its TopRouter option uses a gridless, topological algorithm that Autodesk says typically needs significantly fewer vias. Autodesk lists routing up to 16 layers at once, plus blind and buried vias.
EasyEDA Pro has Auto Routing under the Route menu, for all nets, selected nets or one part's nets, with a choice of JRouter or HRouter engines and settings for corner style, via count and speed versus completion. If the result falls short, EasyEDA's docs point you to DSN export and Freerouting.
KiCad: an interactive router, not an autorouter
KiCad 10 (10.0.7 is the current release) ships an interactive push-and-shove router. It can also auto-complete selected connections with Attempt Finish Selected (Shift+F), but its manual calls that a limited form of autorouting: one track at a time, on the current layer, with no vias.
For full-board autorouting, KiCad exports Specctra DSN and imports SES, which is how Freerouting is used. Community plugins add more: OrthoRoute is a GPU-accelerated KiCad plugin built for very dense boards such as backplanes, KiCadRoutingTools is an alpha Python and Rust router announced in February 2026, and DeepPCB has a KiCad plugin that sends the board to its cloud engine. Our KiCad autorouter guide walks through each round trip.
How AI autorouters differ from traditional ones
A traditional router follows fixed rules and search: find a path, and when it gets stuck, rip up earlier tracks and retry. An AI router adds a learned model. It proposes routes or whole layouts, scores them against design rules and other checks, and keeps exploring. The trade-offs are that your design goes to the vendor's servers unless you buy a self-hosted or enterprise deployment, and that you pay per project or per hour once the free allowance ends.
Quilter calls its approach physics-driven. Its site says it uses reinforcement learning to explore thousands of candidate boards, handles placement as well as routing, and returns candidates for you to review. It says most boards go through 2 to 5 upload, review and adjust cycles. Results come back as Altium, Cadence Allegro, Siemens Xpedition or KiCad files.
DeepPCB, from InstaDeep, describes itself as a learned routing engine built on reinforcement learning. It routes a board you have already placed, and its pitch is that it takes the routine routing while your engineers keep the critical nets. It reads Altium, KiCad (through a plugin), EasyEDA, Zuken, OrCAD, Allegro and Eagle designs, or anything that exports Specctra DSN.
Read the free terms before you upload. Quilter's free tier is for personal, academic and eligible small-team use, and on that tier Quilter says it uses board metadata (outline, footprints, constraints) and input files to generate training puzzles for its engine. DeepPCB's trial is one board, up to 30 minutes, 4 layers, 150 airwires and 100 components; paid hours raise the limits to 8 layers, 1,200 airwires and 1,000 components.
Where ProtoFlow fits (our product)
ProtoFlow is a free desktop PCB design app for Windows, macOS and Linux. It is a full schematic and PCB editor, not a routing service, and its auto-router is one tool inside it. The Auto-Route panel has presets (Fast 2-layer, Balanced 2-layer, 4-layer with planes, Aggressive reroute), lets you choose which copper layers it may use, can route only unrouted nets and preserve your manual copper, and can build and repair power and ground planes. When it finishes it reports completion, tracks and vias added, runtime and any airwires left.
ProtoFlow also has an AI agent, ProtoFlow Studio, that works from a written brief: it chooses parts, draws the schematic, places and routes the board, and runs DRC and ERC as it works. You still review the result.
It opens KiCad, Altium and EAGLE projects and exports KiCad files, so you can route a board in ProtoFlow and check it in KiCad, or hand it to any router above. Files stay on your machine. If you export Gerbers with open DRC errors, ProtoFlow asks you to review them first.
ProtoFlow routing evidence, checked in KiCad
We publish routing numbers only from runs that KiCad itself checked. On LG AI Research's public PCBWorld-Bench, ProtoFlow Studio with Claude Opus 5.5 left 98 of 99 small boards clean (one attempt per board) and 30 of 30 medium-board attempts clean (ten boards, three attempts each). Every attempt counted, each attempt had a 30-minute limit, and a board counts as clean only when every net is connected and KiCad's design-rule check finds zero errors.
On IO Rodeo's open-source Rodeostat shield, we kept the designer's placement, removed every track and via, and let Studio route it. KiCad 8 found 372 of 372 connections made and zero errors, with no part moved, including after KiCad refilled the pours. The run took 42 minutes 47 seconds and needed one operator reminder.
ProtoFlow's router on its own, with no AI model, scored 0.919 on the small boards and 0.900 on the medium ones under the same check. These results are evidence for those boards only. They are not a claim that ProtoFlow routes any board, and the full method is on the benchmark page.
How to choose
Your board is in KiCad and you want a free option: try Freerouting through DSN and SES, or open the .kicad_pcb in ProtoFlow, route it there, and check it back in KiCad. Our KiCad autorouter guide covers both.
Your board is in Altium, Fusion or EasyEDA: start with the router you already have. It already knows your rules and keeps everything in one file.
The board is dense and you want a service to attempt the whole layout: trial Quilter if you meet its free-tier terms, or DeepPCB if the board fits its trial limits. Upload a board you have already routed by hand, so you have something to judge the result against.
You are starting from a circuit idea, not a placed board: a tool that does schematic, placement and routing in one place saves the export steps. That is the case ProtoFlow is built for.
High-speed, RF or switching power layouts: route those nets by hand, whatever tool you use, and let automation fill in the rest.
Decision Matrix
Criteria
Traditional autorouters
AI autorouters
How it routes
Path search with rip-up and retry, or topological mapping (Altium Situs, Fusion TopRouter).
A learned model proposes and scores many candidates (Quilter and DeepPCB both describe reinforcement learning).
Placement
Yours. They route the placement you give them.
Quilter also places parts. DeepPCB routes a board you have placed.
Where it runs
On your machine or inside your CAD tool.
On the vendor's cloud, with self-hosted or enterprise deployments for larger teams.
Cost
Free (Freerouting, EasyEDA, ProtoFlow) or included with a paid CAD tool (Altium, Fusion).
Free tier or trial, then per project (Quilter) or per hour (DeepPCB).
Iteration
Rerun locally as often as you like.
Upload, wait for the run, review candidates, adjust and resubmit.
Your data
Stays with your CAD files.
Uploaded to the vendor. Read the free-tier data terms first.
Checking the result
Run DRC in your CAD tool after routing (after importing the SES file, for Freerouting).
Results come back as files for your CAD tool. Run DRC there before you order.
Migration Steps
01Finish placement first: connectors, mounting holes and anything mechanical, then decoupling capacitors next to the pins they serve.
02Set your fab's rules before routing: track width and clearance, via drill and annular ring, and net classes for power.
03Route and lock the critical nets by hand: USB and other differential pairs, clocks, switching-regulator loops and RF.
04Run the autorouter on the remaining nets, and try more than one setting or layer count.
05Run DRC in the tool you will build from, fix what it flags, and open the Gerbers in a viewer before you order.
How This Comparison Was Checked
Reviewed on: 2026-10-19
Methodology
Read each router's official documentation, repository or pricing page on October 19, 2026: Freerouting on GitHub, the KiCad 10 PCB Editor manual, Altium's Situs documentation, Autodesk's Fusion Autorouter help, EasyEDA Pro's Auto Routing docs, and the Quilter and DeepPCB product and pricing pages.
Described each tool only as far as those sources support. We have not run Quilter, DeepPCB, Situs, Fusion or EasyEDA on our own test boards, so this page does not rank them by routing quality.
ProtoFlow routing numbers come only from runs that KiCad checked, with their conditions stated, and they are reported on their own rather than next to other tools.
Findings
Freerouting 2.5.0 (October 5, 2026) is the current free, GPL-3.0 router. It reads a Specctra DSN file and writes an SES session file that your CAD tool imports back.
KiCad 10 has an interactive router that can finish selected connections one track at a time, but no full-board autorouter. It exports Specctra DSN for external routers.
Quilter's free tier is limited to teams under 10 people and $50K revenue. DeepPCB's free trial is one board, up to 30 minutes, 4 layers and 150 airwires.
Frequently Asked Questions
What is the best PCB autorouter?
It depends on your CAD tool and your board. For a free, tool-neutral router, Freerouting. Inside Altium, Fusion or EasyEDA, the built-in router keeps your rules in one place. For a cloud service that attempts placement and routing on a dense board, Quilter; for cloud routing of a placed board billed by the hour, DeepPCB. ProtoFlow, our product, is a free desktop editor with its own auto-router and an AI agent. Test any of them on a board you have already routed by hand.
Is there a free PCB autorouter?
Yes. Freerouting is free and open source (GPL-3.0). EasyEDA Pro's router is in EasyEDA's free plan, and ProtoFlow's auto-router is in ProtoFlow's free plan. Quilter is free only for personal, academic and eligible small-team use (under 10 people and $50K revenue). DeepPCB has a one-board, 30-minute trial, then paid hours.
Are AI autorouters better than traditional autorouters?
Sometimes, on some boards. AI routers explore many candidate layouts instead of committing to one search, and Quilter also handles placement. But most published comparisons come from the vendors themselves. The fair test is your own board: route it with two tools, run the same DRC, and compare how much cleanup each result needs.
How does AI PCB autorouting work?
A model trained with reinforcement learning proposes tracks or whole layouts, the system scores each candidate against design rules and other checks, and it keeps the best. Quilter and DeepPCB both describe their engines this way. You upload a design, the service runs on its servers, and you bring the routed files back into your CAD tool to check.
What is a physics-driven PCB autorouter?
It is the term Quilter uses for its approach. Quilter says its engine uses reinforcement learning to explore thousands of generated candidate boards and applies physics and DRC checks while it iterates, rather than routing to geometry rules alone. Treat that as the vendor's description, and check any result with your own DRC and review.
Is Quilter a good AI PCB autorouter?
It is one of the main options when you want a cloud service to place and route a whole board. It returns candidates as Altium, Cadence Allegro, Siemens Xpedition or KiCad files, it is free for eligible small teams, and otherwise it is priced per project by the number of pins to route. We have not benchmarked it ourselves, so test it on a board you know well. Our Quilter vs DeepPCB page compares the two cloud services directly.
Should I use an autorouter at all?
For prototypes, dense digital sections and boards that change often, yes: it saves hours. Route high-speed pairs, clocks, switching loops, RF and high-current paths by hand first and lock them, then autoroute the rest. Altium and Autodesk give the same advice in their own router documentation.
Can I run DRC after AI routing in my own CAD tool?
Yes, and you should. Quilter returns native Altium, Cadence Allegro, Siemens Xpedition or KiCad files, DeepPCB's KiCad plugin brings the routed result back into your KiCad project, and Freerouting writes an SES file you import back. Run DRC with your fab's rules in the tool you will generate Gerbers from.
Does ProtoFlow have an autorouter?
Yes. ProtoFlow's PCB editor has an auto-router with presets, layer selection, plane building and a completion summary, plus manual track and via routing. Its AI agent, ProtoFlow Studio, can place and route a board from a written brief. In KiCad-checked runs on LG AI Research's PCBWorld-Bench, Studio with Claude Opus 5.5 left 98 of 99 small boards clean (one attempt per board) and all 30 medium-board attempts clean, every attempt counted. That is evidence for those boards, not a promise for yours.
