Viability Sprint

PROTOTYPE — Viability Sprint landing page for innovate.engineer/viability-sprint | BG4 Brand | April 2026
100% Free — No card required

Validate your product idea in around 2 hours

The Viability Sprint is an AI-guided framework that takes your raw product idea and delivers a structured specification, realistic timeline, indicative costs, and clear next steps. Built from 280+* real product developments.

No signup required
Your idea stays private
Works at your pace
What you’ll walk away with
Product Specification
Development-ready brief for your idea
Realistic Timeline
Confidence-rated development stages
Indicative Costs
Budget ranges you can plan around
Risk Assessment
Technical and commercial risk flags
Clear Next Steps
Exactly what to do after the sprint
280+*
Products developed
40+
Years engineering experience
10
Stage proven framework
98
Activities covered

* Cumulative products developed across engagements led by the principal engineer over 40+ years in practice.

Six stages from idea to development-ready

The Viability Sprint walks you through a structured process that real engineering teams use — adapted so AI handles the heavy lifting while you focus on your idea.

Stage 1
Idea Capture
Define your product concept, target user, and the problem you’re solving
AI-guided
Stage 2
Discovery
Market research, competitor landscape, and user needs analysis
AI-guided
Stage 3
Innovate
Feature prioritisation, differentiation strategy, and IP considerations
AI-guided
Stage 4
Evaluate
Technical feasibility, risk assessment, and commercial viability scoring
AI-guided
Stage 5
Define
Specification, requirements, timeline, and indicative cost estimates
AI-guided
Stage 6
Development-Ready
Complete brief with prioritised next steps and recommended path forward
AI-guided

All 6 stages delivered by AI, at your pace. Stages 7–10 (prototyping, testing, tooling, manufacturing) are available through our Expert Review and engineering team.

Everything you need to make a decision

The sprint produces a structured output you can act on immediately — or take to investors, co-founders, or engineering partners.

Product Viability Brief

A structured summary of your concept, market positioning, and commercial opportunity. The foundation everything else builds from.

Prioritised Specification

MoSCoW-prioritised requirements (Must / Should / Could / Won’t) so you know what to build first and what can wait.

Risk Assessment

Technical, commercial, and regulatory risk flags with severity ratings. Know what could go wrong before you commit capital.

Indicative Cost Estimates

Confidence-rated budget ranges for development, tooling, and production. Transparent about what’s validated vs. estimated.

Development Timeline

Stage-by-stage timeline from concept through to production, with realistic durations and key decision points marked.

Recommended Next Steps

A clear action plan: what to do next, what to test first, and where professional engineering support adds the most value.

Sample Sprint Output (anonymised)

Viability Brief

Viable — proceed to review

Cost Estimate

Confidence: Medium

Risk Flags

2 risks flagged

After your sprint, you have options

The free sprint stands on its own. But if you want to go further, here’s the clear path forward.

Take it away

Free

Use the sprint output as your product brief. Share with co-founders, investors, or your own engineering team. No strings attached.

Download your brief

Expert Review

£49

A real engineer reviews your sprint output, sharpens the cost estimates, flags things AI missed, and gives you a clear go/no-go recommendation. If the review doesn’t give you a clear next step, we refund the £49.

Book Expert Review →

Get your specification

From £149

Your validated idea turned into branded professional documents — product specification, MoSCoW requirements, and design brief. Ready for investors, manufacturers, or our engineering team at Cast Iron CAD.

View services & pricing →

Questions you’re probably asking

We get it — sharing a product idea with an AI tool feels like a leap. Here’s what you need to know.

Your idea stays yours. The sprint runs through a ChatGPT Custom GPT — OpenAI’s terms prohibit using your inputs to train models. We don’t store, share, or access your sprint data. If you upgrade to an Expert Review, your brief is covered by our standard confidentiality terms. For additional protection, we offer NDA signing before any human review.

Every estimate is confidence-rated (high / medium / low) so you know exactly how much to trust each number. The free sprint gives indicative ranges based on similar product types. The £49 Expert Review narrows these significantly — a real engineer cross-references your spec against actual supplier quotes and manufacturing methods. Think of the sprint as “right ballpark” and the review as “budget you can plan around.”

That’s exactly the point. Finding out your idea has a critical flaw in a free 2-hour sprint is infinitely better than finding out after spending £20,000. The sprint won’t just say “not viable” — it’ll tell you specifically what the blockers are. Often, ideas can be pivoted or de-risked by adjusting the specification. That’s a result, not a failure.

No. The sprint adapts its language and depth to your experience level. Whether you’re a first-time inventor or an experienced engineer looking for a structured process, the AI adjusts. You just need to be able to describe what your product does and who it’s for — the framework handles the rest.

Most people complete it in 1–2 hours, but it’s entirely at your pace. You can pause, come back, and pick up where you left off. Some users blast through in 45 minutes; others spread it over a weekend. There’s no timer and no pressure.

Any physical product — consumer goods, IoT devices, garden structures, medical devices, furniture, industrial equipment, tools, packaging. The framework was built from delivering 280+* real products across every category. If it needs to be designed, manufactured, and sold, the sprint covers it.

Built for people with ideas, not just engineers

First-time inventors

“I have an idea but no idea where to start”

Startup founders

“I need a spec and costs for my pitch deck”

SME product teams

“We need to validate before committing budget”

Design graduates

“I want to take my university project commercial”

Your idea deserves a proper answer

Stop guessing whether your product idea will work. Get a structured specification, realistic costs, and a clear path forward — free, in around 2 hours.

No credit card No signup Your idea stays private Takes under 2 hours

*Based on product concepts assessed across Cast Iron CAD and Innovate Engineer projects since 2018.