B2B Payment Platform: From Concept to $41M Processed in Year 1
A construction payments platform built in 4 months for $118K processed $41.2M in year one with a 0.02% error rate.
Subcontractors on construction projects wait 60–90 days for payment. General contractors juggle payments across dozens of subcontractors per project — each with different payment terms, retainage requirements, and lien waiver workflows — on spreadsheets, manual check cutting, and phone calls.
The founder's vision: one platform where general contractors manage subcontractor payments from contract to release, with automated compliance documentation and flexible payment methods. The technical requirements were demanding — Stripe Connect multi-method payments with custom splits, a compliance engine that blocks payment release until lien waivers, insurance certificates, contract terms, and retainage calculations all verify, clean many-to-many data modeling across contractors, projects, and subcontractors, and a full audit trail with SOC 2 readiness from launch.
The budget ceiling was $150K, because the $2.1M seed round had to fund 18 months of operations including sales — not just engineering.
Months 2–3 built the core platform: a general contractor dashboard with real-time views of outstanding payments, upcoming draws, expiring compliance documents, and audited payment history; and a subcontractor portal for payment schedules, document upload, payment status tracking, and bank account management.
The compliance engine is rules-based and explicit. Before any payment releases it verifies the lien waiver (signed, correct amount and period), the insurance certificate (current, meets contract minimums), contract terms (draw matches schedule, retainage correct), and prior payment settlement. Every rule returns pass/fail with a specific failure reason, so contractors see exactly what blocks each payment. Retainage — typically 5–10% withheld per payment — is tracked per subcontractor per project and released as its own compliance-verified payment event.
Month 4 hardened the system: full payment-flow testing with real Stripe test transactions including 5-day ACH settlement, failures, refunds, and multi-subcontractor splits; edge-case testing like documents expiring mid-settlement and partial draws; SOC 2-ready infrastructure (audit logging, RBAC, encrypted storage, documented change management) without premature certification; and a third-party penetration test whose two medium findings were remediated before launch.
Year 1 performance: $41.2M in total payment volume across 3,847 transactions at a $10,710 average size, serving 67 general contractors and 412 subcontractors. The payment processing error rate was 0.02% — one failed payment, caused by a bank return rather than the platform. Compliance documents auto-verified at 94.6% accuracy with the remaining 5.4% flagged for manual review. Uptime: 99.97%.
For contractors, payment processing dropped from 3–5 business days of check cutting to same-day or next-day ACH. For subcontractors, Days Sales Outstanding fell from a 67-day average to 12 days.
The Year 1 volume at the platform's fee structure demonstrated product-market fit, and the founder raised a $6.2M Series A 14 months after the seed round. The MVP came in at $118,000 over 4 months, with ongoing development and support continuing at $8,500/month.
Most dev shops told us a payment platform would take 8–12 months and cost $300K+. Gigabit delivered in 4 months for under $140K — and the platform has processed $41 million without a single payment error. The double-entry ledger, the idempotency, the compliance automation — these aren't features you see from teams that treat fintech like regular SaaS. Gigabit understood that in payments, reliability isn't a feature, it's the product.
