Collins Kiptoo
Hi, I'm Collins. Backend engineer in Nairobi.

I've built a fintech platform from the first quote to the final payout.

For two and a half years I worked on every part of Cloover's platform: the offers installers send, the checkout and credit check that approve a customer, the contracts and invoices, the money that moves at the end, and the 30-odd services it all talks to. Lately, AI agents that have to show their working.

Email meSee my work

Working European hours from Nairobi. Open to contract or full-time.

Collins Kiptoo
ONE CUSTOMER, START TO FINISH
Cloover platform
Installer builds the offeroffers·✓
Customer checks outcheckout·✓
Credit decisionSchufa, CRIF·✓
Contract signedDocuGenerate·✓
Invoice issuedDE, AT VAT·✓
Customer paysSEPA, Stripe·✓
Installer paidpayout·✓
Steps I built inAll of them
30+integrations wired in
30+
outside services connected through one API layer
6,000+
users on the platform I built across
€300M
guarantee backed by the audit records I designed
5.0
from every client who rated my freelance work
What I'm known for

Three things people come to me for.

Building the whole journey, not one screen of it.

Offers, checkout, credit decisions, contracts, invoices and payments. I know how a change in one shows up in the other five.

The platform

Wiring a product to the outside world.

Credit bureaus, payment providers, CRM, accounting, documents, email, solar data, AI. Through real API calls with authenticated webhooks, not plugins.

The integrations

Knowing how every piece fits.

Five years on Bubble, the engineer new hires were pointed at, and the person a Google Cloud team relied on to rebuild a live platform without losing a customer.

The Bubble side
Selected work

The receipts.

From a platform that finances solar, batteries and heat pumps for households across four countries. Names and amounts stay private. The counts are exact.

Quote → loanoffers, checkout, credit, contract

From an installer's offer to a financed customer.

An installer quotes solar, a battery and a heat pump. The customer checks out and a credit decision comes back. I built the pieces in between: offer and checkout rules (solar at 0% VAT, heat pumps at 19%, checkout locked if an offer changes after signing), the Schufa and CRIF checks with their risk mapping and affordability rule, underwriting alerts, and test data so nothing ever hit a live bureau by accident.

Read the full story
OFFER OF-2291
solar, battery, heat pump
Solar PV, 9.8 kWp0% VAT·✓
Battery, 10 kWh0% VAT·✓
Heat pump19% VAT·✓
Credit checkSchufa·✓
Affordability rulepassed·✓
Contractsigned·✓
StatusFinanced
30+services, one API layer

A platform that talks to everyone.

Payments and banking, credit and sanctions screening, CRM, accounting and collections, contracts and email, solar and address data, and our own AI features. Over 340 calls across 30-plus services, built and maintained through the API connector, with webhooks authenticated and secrets kept out of test.

See the integrations
Bubble Data API115Postmark81HubSpot28DocuGenerate25Stripe17Internal Utils11Nordiska10QuickBooks9Postmark signatures5GCP Checkout4Solar API Insights4Buckaroo3Stripe verification3Bubble Bulk API3AI Features API3Schufa2OpenSanctions2PAIR Finance2ConvertAPI2Google Places2Math.js2Google Solar1OpenCage1OpenAI1Zerobounce1Clicksend1Currency Exchange1BIC lookup1Country data1Stripe Identity1Slack1Partners API1
€300Mguarantee, checked deal by deal

An auditor's question, answered before it's asked.

The European Investment Fund backs part of the loan book and wants proof, per loan, that it qualified. I designed the system that writes that proof the moment a loan is approved. Before building it, I went through the finance team's spreadsheet cell by cell and found three errors nobody had seen.

Read the full story
CountryPASS
Transfer of financial benefitPASS
Margin over cost of fundsPASS · COF 6.35%
OverallELIGIBLE
one record per deal, frozen at approval
289places one missing field was read

The person the new platform asked "how did it work before?"

When the company rebuilt on Google Cloud, new projects never set a customer link the old app depended on in 289 places. I found it, fixed it, lined up invoice timing across both platforms, and kept installers informed through the move.

Read the full story
LegacyBubble. Payments, credit, invoicing. 6,000+ users.
289 refs
Google CloudNew checkout. Customer link never set. Found, fixed.
532 → 157Unmatched payouts after a trace on every payment and a 720-record backfill. 7 batchesEvery live project swept for fee and pricing errors before they reached an invoice. ×12 → compoundingAn interest-rate formula fixed, which mattered every time a loan was split.
A workflow that's 98% right is a workflow somebody fixes by hand every morning.
The sentence I design against
AI, honestly

I use agents every day. I trust them with nothing I can't check.

  • In daily use since 2025.Claude Code and Buildprint inside a large production app. They found a hardcoded secret in a partner webhook and traced a refund bug that was quietly marking refunded invoices as paid.
  • Building now: an agent that matches payments to invoices.Rules first, the model only for the messy remainder, a human for anything it isn't sure about. It goes public with its evaluation numbers, or it doesn't go public.
  • The rule I work by.The agent proposes. The data decides. A match nobody can explain counts as a miss.

More on how I use AI, and what I won't claim

payout reconciler, evalin progress
auto-link rate
to measure
precision
to measure
false links
to measure
cost per 100
to measure
unexplained match
= a miss
How I got here

Actuarial maths, then software, then fintech.

  • 2020

    Insurance data, as an actuarial intern

    Validating data for risk pricing at Jubilee Insurance. Where I learned that a number is only useful if you can say where it came from.

  • 2021

    First clients, on Bubble

    Freelance builds for early-stage founders: booking platforms, internal tools, a QA audit written up as a report.

  • 2022

    Six apps at once, for a US agency

    A marketplace with split payments and escrow, an inventory sync across five sales channels, an app that counts pests from photos.

  • 2023

    Fintech, for a Berlin studio

    Fence, a finance platform for lenders that later raised a $20M Series A, and Koncile, a document-reading tool for finance teams.

  • 2024

    Every part of the Cloover platform

    Offers, checkout, credit checks, contracts, invoicing, payments, compliance and 30+ integrations, on a platform financing 20,000 installations a year.

  • 2026

    Agents that show their working

    Taking everything above into AI systems that are measured before they're trusted.

Building something that has to be right?

collo060@gmail.com
Collins KiptooNairobi, on European hours.
Contract, full-time, or a short paid pilot.