My Role
Co-Founder, Product & Service Designer
Carlos Cabrasco
NUMMA: How $4,133MXN in Ads and 4 Interviews Revealed We Were Solving the Wrong Problem
Timeline:
6 months
Industry:
Fintech B2B/B2C, Tax Compliance, Conversational AI
Why this matters:
SAT (Mexico's tax authority, equivalent to IRS) requires specific XML formats with digital certificate
Invoices must be validated through authorized PAC providers (government-certified third parties)
Non-compliance = invoices rejected, payments blocked
Traditional accounting software costs $30-100/month and has steep learning curves
Mexico has 4.9M independent workers, photographers, architects, consultants—operating informally. To work with corporate clients, they must issue CFDIs (Comprobantes Fiscales Digitales por Internet): digital, cryptographically-signed invoices that meet strict government requirements.
Most independent workers rely on accountants to navigate this complexity. Our hypothesis: accountants are the bottleneck preventing scale.
Hypothesis & Experiment
Before building anything, we ran a lean validation experiment.
Red flag: Entrepreneurs were dramatically more engaged and cheaper to acquire, yet our entire strategy targeted accountants.
Zero conversions told us we needed deeper understanding before iterating.
Experiment Design
Method:
Two landing pages (one for accountants, one for entrepreneurs) + targeted ad campaigns
Channels:
Meta + Google Ads
Investment:
$4,133 MXN
Duration:
6 weeks
Metric
Accountants
Entrepreneurs
Difference
Leads Generated
48
42
Similar
Contact Rate
58.3%
95.2%
3x higher
Cost per Lead
$58.40 MXN
$36.11 MXN
40% cheaper
Instead of optimizing ads, we paused and invested in qualitative research.
Ethnographic Interviews
Participants: 4 independent professionals
Deep Research
Rogelio (Business Consultant)
"It's so hard to find a good accountant, really hard. She's so good that she has too much work, saturation problem."
Invoice delays critically impact cash flow - misses corporate payment dates due to 1-2 week accountant delays.
Xavier (Architect)
"Finding the correct product/service codes is confusing. I use Google AI to search SAT codes."
Complex government forms and SAT product code classification creates friction and cancellation errors.
Mezcal Producer
"Extreme seasonality complicates monthly payments, I need to see the invoice visually before sending."
Seasonal business model (4 peak months, 8 dead months) makes monthly subscription pricing impractical.
Sofia (Photographer)
Previous accountants had zero transparency. I help other photographers invoice because they can't do it themselves."
Lack of fiscal transparency and visibility into tax compliance - wants educational guidance, not just transaction processing.
This shattered our core assumption. We thought entrepreneurs wanted independence from accountants. The research revealed they wanted faster service from their existing accountant.
Key Findings
Most independent workers rely on accountants to navigate this complexity. Our hypothesis: accountants are the bottleneck preventing scale.
Carlos Cabrasco
NUMMA: How $4,133MXN in Ads and 4 Interviews Revealed We Were Solving the Wrong Problem
My Role
Co-Founder, Product & Service Designer
Timeline:
6 months
Industry:
Fintech B2B/B2C, Tax Compliance, Conversational AI
Mexico has 4.9M independent workers, photographers, architects, consultants—operating informally. To work with corporate clients, they must issue CFDIs (Comprobantes Fiscales Digitales por Internet): digital, cryptographically-signed invoices that meet strict government requirements.
Why this matters:
SAT (Mexico's tax authority, equivalent to IRS) requires specific XML formats with digital certificate
Invoices must be validated through authorized PAC providers (government-certified third parties)
Non-compliance = invoices rejected, payments blocked
Traditional accounting software costs $30-100/month and has steep learning curves
Most independent workers rely on accountants to navigate this complexity. Our hypothesis: accountants are the bottleneck preventing scale.
Hypothesis & Experiment
Before building anything, we ran a lean validation experiment.
Experiment Design
Method:
Two landing pages (one for accountants, one for entrepreneurs) + targeted ad campaigns
Channels:
Meta + Google Ads
Investment:
$4,133 MXN
Duration:
6 weeks
Metric
Accountants
Entrepreneurs
Difference
Leads Generated
48
42
Similar
Contact Rate
58.3%
95.2%
3x higher
Cost per Lead
$58.40 MXN
$36.11 MXN
40% cheaper
Red flag: Entrepreneurs were dramatically more engaged and cheaper to acquire, yet our entire strategy targeted accountants.
Zero conversions told us we needed deeper understanding before iterating.
Deep Research
Instead of optimizing ads, we paused and invested in qualitative research.
Ethnographic Interviews
Participants: 4 independent professionals
Rogelio (Business Consultant)
"It's so hard to find a good accountant, really hard. She's so good that she has too much work, saturation problem."
Invoice delays critically impact cash flow - misses corporate payment dates due to 1-2 week accountant delays.
Xavier (Architect)
"Finding the correct product/service codes is confusing. I use Google AI to search SAT codes."
Complex government forms and SAT product code classification creates friction and cancellation errors.
Mezcal Producer
"Extreme seasonality complicates monthly payments, I need to see the invoice visually before sending."
Seasonal business model (4 peak months, 8 dead months) makes monthly subscription pricing impractical.
Sofia (Photographer)
Previous accountants had zero transparency. I help other photographers invoice because they can't do it themselves."
Lack of fiscal transparency and visibility into tax compliance - wants educational guidance, not just transaction processing.
This shattered our core assumption. We thought entrepreneurs wanted independence from accountants. The research revealed they wanted faster service from their existing accountant.
Key Findings
Wrong problem: Accountants don't need more clients, entrepreneurs need faster turnaround
Trust barrier: Direct-to-consumer tax solutions perceived as risky
Cash flow timing is critical: Payment cycle delays cost real revenue
Speed is the bottleneck, not the accountant: Most value their accountant relationship
Most independent workers rely on accountants to navigate this complexity. Our hypothesis: accountants are the bottleneck preventing scale.