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Vaultline went from napkin sketch to funded fintech app in 14 weeks

A first-time founder had a thesis about helping freelancers manage irregular income. We validated the market, prototyped in code, and built the MVP that secured their $2.1M seed round.

Vaultline

SMOOTHED BALANCE
$4,280
↑ Stable vs. $1,200-$8,400 raw income
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Client: Acme Corp+$3,200
Tax Vault (auto)-$960
Emergency Fund-$320
Smoothed Payout+$4,280
Stripe: Workshop+$450

Insights

AI INCOME FORECAST

Based on your invoicing pattern, expect $6,800 next month. Consider increasing your tax vault by 3%.

TAX READINESS

You've set aside $12,400 for estimated taxes. You're on track for Q2.

Saved82%
SPENDING PATTERN

Your SaaS subscriptions increased 22% this quarter. Three tools overlap in functionality.

SaaS spend$340/mo
14 wk
Idea to live MVP
$2.1M
Seed round secured
1,200
Waitlist signups
89%
Beta retention (30-day)

A strong thesis, no validation

The founder, a former freelance designer, experienced the pain of irregular income firsthand: feast-or-famine cash flow, tax surprises, and the constant anxiety of not knowing what next month looks like. She believed an intelligent "income smoothing" tool could solve this for millions of freelancers.

The problem was clear, but the solution was not. Should it be a banking product? A budgeting tool? An AI advisor? She had no technical co-founder, limited runway, and needed to get to a fundable MVP fast.

Two weeks to find the signal

We ran a focused validation sprint before writing a single line of product code. The goal: figure out what freelancers would actually pay for, and what was just a nice-to-have.

1
User Interviews (n=24)

Talked to freelancers across design, dev, writing, and consulting. Income anxiety was universal, but the trigger to act was tax season, not daily budgeting.

2
Competitive Landscape

Mapped 18 competitors. Most were generic budgeting tools. None combined income smoothing with automated tax vaulting for freelancers specifically.

3
Landing Page Test

Built a one-page site describing the core concept. 1,200 email signups in 10 days from targeted Reddit and Twitter posts. Conversion rate: 14.2%.

4
Willingness to Pay

Surveyed waitlist. 67% said they'd pay $9-15/month. The income smoothing + tax vault combo was the highest-rated feature pair by a wide margin.

From validated concept to working app in 12 weeks

With validation data in hand, we scoped the MVP to two core features: automated income smoothing (analyzing deposit patterns and distributing a steady "paycheck") and smart tax vaulting (auto-setting aside estimated taxes with each deposit).

We built a working code prototype in week one that the founder could demo to potential investors. By week four, the beta was live with 50 waitlist users providing daily feedback. We iterated through three major pivots based on that feedback before locking the v1 feature set.

Weeks 1-2

Validation Sprint

User interviews, competitive analysis, landing page test, willingness-to-pay survey

Week 3

Code Prototype

Working prototype with mock data, investor-ready demo, core UX flow validated

Weeks 4-8

Beta Development

Plaid integration, income smoothing algorithm, tax vault logic, 50-user beta

Weeks 9-12

Iteration + Polish

Three major pivots from user feedback, AI insights feature, App Store submission

Week 14

Seed Round Closed

$2.1M raised with live product, 1,200 waitlist, and 89% beta retention as proof points

React Native Node.js Plaid API PostgreSQL OpenAI Stripe AWS Lambda
"I came in with a thesis and some sketches. Signal Labs helped me figure out what was actually worth building, then built it with me. The code prototype in week one is what got my first investor meeting. The live beta is what closed the round."
Priya Sharma, Founder & CEO, Vaultline

Funded, live, and growing

Vaultline launched on the App Store with 1,200 waitlist users converting at 34% in the first week. Thirty-day retention hit 89%, well above the fintech benchmark of 25-30%. The income smoothing algorithm reduced users' self-reported financial stress scores by 41% in the first month.

The seed round closed at $2.1M, led by a top fintech-focused fund. The founder credited the speed of validation and the quality of the working product as the two factors that differentiated her pitch.

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