Spark, Signal, Prototype — Which Build Package When

Three build packages at aunomo.tech, three clearly different economic logics. Most solopreneurs and small teams arrive with the assumption: "We want a tool / a prototype / a web app" — and realise in the first conversation that the three terms mean three different things. This piece explains when which package is the right choice, anchored in three real scenarios.

The three packages at a glance

PackagePriceDurationOutputCreditable againstThe Spark2,490 €2–3 daysA single tool, ready to usenot creditableThe Signal3,900 €4–6 daysClickable prototype with real AI logicThe PrototypeThe Prototype6,900 €7–10 daysProductive web app with database + auth + AIThe Build

The packages are cumulatively designed: Signal does not build on Spark, Prototype builds on Signal. Anyone planning the full build can validate with Signal and upgrade to Prototype — or start directly with Prototype.

Scenario 1: The Spark — the internal tool

Context. A solo consultant in Hamburg spends two hours every Wednesday assembling proposal PDFs from an Excel sheet and three text blocks. Standardised inputs, standardised output, no creative component — pure reproducible work.

What Spark delivers. A single-page web tool: upload the Excel sheet at the top or type the inputs into five fields, one click → structured PDF appears, done. Tool runs on a subdomain of her business, password-protected, used by her and her one intern.

Why not Signal or Prototype? There are no user workflows, no auth depth, no database for persistent user data. It is a tool, not a system. Investment volume of 2,490 € corresponds to roughly ten weeks of her saved Wednesday hours — amortisation well under a quarter.

Typical solopreneur profiles for Spark:

• Consultants with standardised output formats (proposals, reports, audits)
• Agency owners with onboarding routines that are Excel-driven
• Coaches with assessment tools (client enters data, tool generates evaluation)
• Operational specialists automating repeatable data conversion

What Spark does not cover. Multiple users with own accounts, persistent database, multi-step workflows with states. As soon as that enters: Signal or Prototype.

Scenario 2: The Signal — the investor prototype

Context. A tech founder in Berlin has an idea for an AI-powered code-review tool. Pre-seed round coming up, three investors want to see a clickable demo in four weeks. The idea must become tangible without the full software needing to be built.

What Signal delivers. A functioning prototype with real AI integration (e.g., Anthropic or Gemini API), real code input, real code-review output. Clickable, deployable on a Vercel URL, demonstrable. Authentication minimal (one test login is enough), database optional.

What Signal is not. It is not productive. It is not scalable. It is not designed for end users. It is a proof of concept for a specific demo situation: investor pitch, internal stakeholder meeting, sales demo with a pilot client.

Why not directly Prototype? Because the founder does not yet know whether the investment justifies the full build. Signal costs 3,900 € and is 100 % creditable against The Prototype — with positive investor reaction he pays only the difference (3,000 €) for the productive version. With negative reaction he has a demonstrator for the next pitch.

Typical founder profiles for Signal:

• Pre-seed founders with investor demo needs
• Solopreneurs with internal stakeholder validation (e.g., CTO wants to see concept)
• Spin-off founders with grant proposal validation
• Consulting firms validating a new service product before market launch

When Signal does not fit. When the tool is supposed to be used productively internally. When real users should log in in the coming weeks. When database persistence is needed from day one. Then: Prototype.

Scenario 3: The Prototype — the productive web app

Context. A solo energy consultant in Munich serves ten to twenty advisory mandates per year, each with its own solar ROI calculation. Excel-based so far. He wants a web app where his clients enter their consumption, the app calculates amortisation, and generates a proposal-ready PDF. The tool should be productive today, possibly extended in twelve months with supplier comparison and subsidy database.

What Prototype delivers. Complete system: user login (Supabase Auth, EU region), database schema for consumption data and calculation results, AI integration for intelligent recommendations ("based on your profile we recommend the following modules"), PDF generator, deployment to his custom domain, full code handover to him.

What Prototype is not. It is not a full build. Complex multi-module architectures, native mobile apps, multi-tier subscription logic — that is The Build (on request, creditable). Prototype is the productive first version that can be scaled and extended in twelve months.

Why this step makes sense. The consultant sits between two options: no-code (Bubble, Softr — would hit his specific AI needs) and full agency (60,000 €, nine-month duration — overkill). Prototype is the third option: senior build, fixed price, productively usable after seven to ten days, fully owned.

Typical solopreneur and tiny-team profiles for Prototype:

• Solo specialists with clearly defined client interaction (energy advisory, insurance, tax advisory)
• Small agencies (3–10 people) with internal CRM needs not covered by off-the-shelf tools
• Founders with validated ideas (e.g., after The Signal) entering the productive phase
• Specialists with AI-driven workflows wanting to make them directly accessible to clients

Creditability after Prototype. 100 % toward The Build. Anyone scaling in twelve months pays only the difference.

The decision logic in three questions

Three questions usually clarify the choice quickly:

Question 1: Will real users productively use the tool in the coming weeks?

• Yes → Prototype
• No, only demo / internal validation → Signal
• It is an internal tool only for me → Spark

Question 2: Do you need persistent data between sessions (login, save, recall)?

• Yes, for multiple users → Prototype
• No, or only minimally → Spark or Signal
• Demo data is enough → Signal

Question 3: Are you in a validation phase or a productive phase?

• Validation (investor, internal stakeholders, grant proposal) → Signal
• Productive from day one → Prototype
• Operational efficiency for myself → Spark

If uncertainty remains after these three questions: The Audit (free, 30 minutes) is made for exactly these cases. Output: concrete package recommendation — or the recommendation not to start at all, if the need is not clear.

Frequently Asked Questions

Can I book Spark + Signal + Prototype in sequence? Spark is not creditable, so no in the sense of the creditability logic. Signal → Prototype works (100 % creditable). Spark is an end product on its own.

What does The Build (after Prototype) cost? On request. Typical range for full build based on a Prototype: 25,000–60,000 € depending on scope. Exact price after scope discussion. Prototype 100 % creditable.

Can stack decisions deviate before the package? Standard is Next.js + Supabase + Vercel. Other stacks (Astro, SvelteKit, Cloudflare Workers) possible on request, affecting duration + price. Defined in the scope document before contract signature.

Which package fits for a platform idea (multiple user types, marketplace logic)? Probably none of the three. That is The Build. But: often it is worth a Prototype to validate the platform logic on one user-type side before investing in the full build.

What happens if the Spark tool later needs to grow? Then it is no longer a Spark — but a new build engagement (Signal or Prototype). Spark is an end product, not a first step in a pipeline. Anyone expecting growth in twelve months: Prototype.

When is The Spark the right choice despite its "end product" character? When the tool solves a clearly bounded problem that does not extend into a broader workflow. Examples: PDF converter, email classifier, data formatter, proposal generator. These are tools, not systems.