Head to head
These tools disagree about almost everything: where the design lives, whether AI belongs in the editor, whether you should pay, and whether the browser is the right place to do engineering work. That makes the comparison unusually clear.
Quick answer
Flux is a browser-based collaborative PCB tool with an AI copilot, on a free trial that converts to a paid subscription with metered AI usage. KiCad is free, open source, desktop, offline, and has no AI at all. So the real choice is AI and real-time collaboration on one side, versus zero cost and permanent file ownership on the other. If you want both, ProtoFlow is the third option: a free desktop editor with built-in AI schematic generation, real distributor part import, ERC/DRC, and native .kicad_sch and .kicad_pcb files that stay on your machine.
Last reviewed: 2026-08-09 · By ProtoFlow Engineering Team
| Flux | KiCad 10 | ProtoFlow | |
|---|---|---|---|
| Cost | Free trial, then paid | Free, open source | Free |
| AI copilot | Yes, usage-metered | None | Yes, daily allowance |
| Runs | In the browser | Desktop, offline | Desktop, offline |
| Real-time collaboration | Yes, core strength | Via git | Local files, git-friendly |
| File ownership | Cloud project | Local, open format | Local, native KiCad |
| Export | Supported, plan-dependent | Native, unrestricted | Native KiCad, unrestricted |
Skip the comparison shopping. Try the free one first and see if it does the job.
Download for DesktopReal-time collaboration in a browser is a real capability and Flux does it well. Two engineers in the same design at once, no installation, a link instead of a file, and an AI copilot available inside the editor. For a distributed team doing fast iteration, or for teaching where everyone needs the same environment instantly, that combination is hard to reproduce with desktop tools.
The cost model is the thing to understand upfront: the entry point is a free trial rather than a permanent free tier, and AI features are metered by usage units. That is a reasonable way to price AI compute; it just means your cost scales with how much you use the feature you came for.
Everything about permanence. It is free with no tiers, open source, runs offline on macOS, Windows, and Linux, and stores projects as documented files you own outright. You can version them in git next to firmware, review diffs, and open them in a decade regardless of what happened to any company. For open hardware and for anything with a long service life, that is decisive.
The gap is equally clear: no AI, and a manual capture workflow. You place every symbol and draw every net yourself.
Framed as Flux versus KiCad, you are choosing between AI assistance and file ownership. That framing is an artifact of how these two products happened to be built, not a law of the category. There is no technical reason an AI copilot requires a cloud subscription or a proprietary project format.
ProtoFlow exists in that gap: a free desktop application that generates schematics from plain-English descriptions, imports real components from LCSC, DigiKey, and Mouser, runs ERC and DRC, autoroutes locally, and reads and writes native .kicad_sch and .kicad_pcb files stored on your own machine. The AI is included on the free tier with a recurring daily message allowance rather than metered credits, and nothing about export is paywalled.
Choose Flux if browser-native real-time collaboration is the requirement and a subscription is acceptable. Choose KiCad if cost and file ownership are non-negotiable and you are happy drafting by hand. Choose ProtoFlow if you want the AI drafting without the subscription or the cloud dependency, and you want the output to be a KiCad project either way.
| Criteria | ProtoFlow | Flux or KiCad |
|---|---|---|
| AI schematic generation | Yes, free daily allowance. | Flux: metered. KiCad: none. |
| Cost | Free. | Flux: paid after trial. KiCad: free. |
| Where files live | Local, native KiCad format. | Flux: cloud. KiCad: local. |
| Works offline | Yes. | Flux: no. KiCad: yes. |
| Real-time co-editing | Not the focus. | Flux: yes, core strength. |
Reviewed on: 2026-08-09
Flux is better at real-time browser collaboration and ships an AI copilot. KiCad is better at cost, file ownership, offline work, and long-term maintainability. They are optimized for different things rather than one being an upgrade over the other.
Flux offers a free trial rather than a permanently free tier, converting to a paid subscription with usage metering on AI features. KiCad and ProtoFlow are both genuinely free.
Yes. ProtoFlow is a free desktop editor with built-in AI schematic generation, real LCSC/DigiKey/Mouser part import, ERC/DRC, and native KiCad export, with a recurring daily AI message allowance on the free tier.
Flux supports export, with availability depending on your plan. As with any cross-tool transfer, verify footprints and net connectivity after import and re-run ERC and DRC before trusting the result.
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