Flux - Copilot for PCBs Building
Flux · Coding · Productivity
Flux is a browser-based AI hardware engineer that turns a plain-language brief into a schematic, a routed PCB, and fab-ready files. It checks its own work in simulation, with no install.
About Flux - Copilot for PCBs Building
What Is Flux
Flux is a cloud platform for building circuit boards, and it pitches itself as an AI hardware engineer rather than another piece of circuit board design software. The idea is closer to a PCB copilot: you set the goal, it does the drawing, checking, and sourcing around you. You describe what the device should do, Flux plans the job, researches parts, draws the schematic, places and routes the board, then hands back files you can send to a manufacturer. Your job shifts from dragging symbols to reviewing decisions.
The whole AI PCB design flow lives in one browser tab. Schematic capture, PCB routing, design rule checks, circuit and thermal simulation, mechanical CAD, and firmware share the same project, so a connector change shows up in the enclosure model and the board at once. The parts library pulls live stock and pricing from distributors, which means the bill of materials is something you can actually order instead of a wish list.
The limits matter too. Flux is an assistant, not an autopilot. Dense or high-speed boards still need an engineer to review placement and routing, and every AI action burns Agent Compute Units (ACUs), a metered budget that can run dry in the middle of a project. Boards are also cloud-only, so there's no desktop build to fall back on when the connection drops.
Getting Started
- Create a free account at flux.ai and start a project from a blank board, a template, or an imported KiCad, Altium, Eagle, or EasyEDA file.
- Describe the goal in the chat panel, including voltage rails, interfaces, board size, and any parts you already have. Flux asks follow-up questions before it plans.
- Approve the plan, then review the schematic it generates. Change parts, pin assignments, or passive values by asking for the edit or by editing the drawing by hand.
- Ask for placement and routing, run the electrical and design rule checks, then export Gerbers, a BOM, and pick-and-place files, or send the board straight to a partner fab for a quote.
Product Information
A quick look at Flux - Copilot for PCBs Building's pricing, supported platforms, and performance.
Best for
The users, tasks, and scenarios where this tool fits best.
Users
- Hardware founders without a full EE team
- Firmware developers who need a matching board
- Small engineering teams
Tasks
- Turning a spec into a first schematic
- Routing selected nets
- Checking a design before an order
Scenarios
- A first prototype board for a sensor or controller product, where speed matters more than squeezing out the last bit of cost.
- A respin after a part goes end of life, since the library shows substitutes that are in stock at Digi-Key, Mouser, or LCSC.
- Bringing an existing Altium or KiCad project into a shared workspace so a distributed team can review changes in the browser.
Key features
Plain-Language Design Briefs
Flux takes a written requirement like "a WiFi humidity sensor with USB-C charging" and turns it into a plan with a parts list, a schematic outline, and a routing strategy. Before it starts, it asks about supply voltage, interfaces, and size limits. You approve the plan, which keeps the AI from wandering off on a design you never asked for.
Schematic Capture From Real Parts
Every symbol comes attached to a footprint, a 3D model, and a datasheet. Flux reads that datasheet when it sizes passives, sets I2C pull-ups, and adds decoupling caps, so the schematic reflects what the part actually needs. The result stays editable, and engineers can redraw any section by hand.
Agentic PCB Routing
You can ask Flux to route the entire board or only the nets you name. Follow-up requests in chat handle differential pairs, matched lengths, trace widths, and layer changes. Manual routing tools are still there for the traces that carry the design intent, which is where experienced engineers spend their time anyway.
Verification That Runs Continuously
Electrical rule checks and design rule checks run as you work rather than at the end. On top of that, Flux runs SPICE simulation on the schematic and electromagnetic plus thermal simulation on the routed board, so a hot regulator or a bad impedance shows up before fabrication.
Live Parts, Stock, and Fab Quotes
The public library holds more than 734,000 parts with symbols, footprints, and pricing. Stock and cost come from Digi-Key, Mouser, LCSC, and other distributors, and board quotes come from JLCPCB, PCBWay, OSH Park, and AISLER inside the same view. That turns sourcing from a spreadsheet chore into a check you do while choosing a part.
Firmware Written for the Board
Flux writes firmware for the board it just designed, with targets that include Arm Cortex-M, RISC-V, AVR, and Raspberry Pi Pico class chips. It builds the code, analyzes it, and runs unit tests, so the pins and peripherals match the schematic instead of drifting out of sync.
Collaboration, Version History, and Imports
Projects support comments, visual design review, and restore to an earlier version, and they import complete projects from Altium, Cadence, KiCad, Siemens, Zuken, Autodesk, and EasyEDA. Cloud-based PCB routing also means a reviewer can open the exact board being discussed instead of a screenshot.
Pros and cons
Pros
- One workspace covers brief, schematic, layout, verification, BOM, and fab files, which removes most of the handoff between tools.
- Checks run while you work, so rule violations and thermal problems surface before you spend money on boards.
- The parts library ties symbols and footprints to live distributor stock, so a design is orderable the day it is finished.
- Imports from Altium, KiCad, Eagle, and EasyEDA mean an existing project can move in without a redesign from scratch.
Cons
- AI work is metered in ACUs with a monthly allowance, and extra usage costs $2 per ACU, so heavy agent use makes the monthly bill hard to predict.
- Placement and routing output still needs an engineer's review on dense or high-speed designs, which means the tool speeds up a first pass rather than finishing the board.
- Everything runs in the browser, so a long session depends on a stable connection and there is no offline desktop version.
- After the trial, free access covers public projects and the community only, so private designs need a paid plan.
Frequently asked questions
It depends on the job. Flux handles schematic capture, layout, routing, and checks well enough for prototypes and small production runs, and it reads Altium and KiCad projects when you need to bring work in. Teams with sign-off processes built around a desktop EDA suite usually keep that suite and use Flux for the AI-driven parts of the flow.
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