2026
Invention Space
A per-project engineering firm for inventors — a free workspace to track ideas, and paid feasibility reviews where AI does the legwork and a real engineer signs the opinion.
Stack
Next.js 16 · React 19 · NestJS 11 · Firebase
Outcome
Free, unlimited idea tracking with notes, research, and document storage — no credit card
The problem
An independent inventor with a physical product idea has no affordable way to find out whether it is worth pursuing. A patent attorney and a design consultancy both cost thousands before anyone tells you the honest answer, so most people either spend real money on an idea that was never going to work, or shelve a good one because they could not justify the up-front check. Invention Space needed to sell a small, concrete engagement instead of an open-ended consulting relationship — and to do it without a subscription.
The build
The product splits cleanly in two. The workspace is free and unlimited: track ideas, keep notes and research attached to the right project, and upload sketches, patents, and product photos. The review is paid, priced per project, and starts at $199. Between the two sits an AI research pass that prepares the ground — market and prior-art legwork — so the engineer spends their time on judgment rather than gathering. The front end is Next.js 16 and React 19; the API is NestJS 11 on Firebase Cloud Functions with Firestore behind it, Stripe for per-project checkout rather than recurring billing, and Socket.IO for live status while a review is in flight.
Sometimes the answer an inventor pays for is “stop before you spend more.” That is the part that makes this a different product from the idea-validation tools it sits next to — the report is allowed to tell you no, because a working engineer is signing it rather than a scoring algorithm optimizing for engagement.
The business model drove the architecture more than the feature list did. Most tools in this space sell a subscription and quietly hope you forget to cancel. Giving the workspace away instead means the free tier has to be genuinely good — unlimited ideas, notes attached to the right project, sketches and patents stored alongside them — because it is the whole product until the day someone wants an opinion. Stripe is wired for per-project checkout rather than recurring billing, which is a meaningfully different flow from the SaaS default and changes what the account model has to support.
How the AI is positioned mattered to the build. It runs the legwork once payment lands — market context, prior art, the groundwork that would otherwise eat days — and then a mechanical or electrical engineer reads it, forms a judgment, and signs the report. Nothing ships that a person did not write. That boundary is deliberate: the site says “AI to prep, not to pretend,” and the system is built so that claim stays true rather than being a tagline.
The rest follows from wanting a submitted review to feel like it is moving. Socket.IO drives live status so a paid submission reports progress instead of sitting silent for a week, and the NestJS API generates the delivered documents directly rather than handing off to a separate service.
See it at inventionspace.com.
The outcome
Inventors get a free place to work and a priced, bounded way to get an expert opinion when they want one. Three tiers cover the range: a $199 Feasibility Review, a $699 Full Assessment, and an Engineering Engagement from $2,500 for end-to-end product development. Reports run about two weeks end to end, averaging five days of turnaround, and every one is written by a mechanical or electrical engineer — the AI prepares, it does not sign off.
- Free, unlimited idea tracking with notes, research, and document storage — no credit card
- Three per-project tiers: $199 Feasibility Review, $699 Full Assessment, $2,500+ Engineering Engagement
- 5-day average report turnaround; roughly two weeks from submission to delivered report
- 100% human-reviewed — AI handles research prep, a licensed engineer writes the opinion
- Stripe per-project checkout instead of a subscription, so inventors pay only when they want a review
- Next.js 16 + React 19 front end on a NestJS 11 API, Firestore, and Socket.IO for live review status
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