Fractional CTO for
FinTech & Micro-Lending.
I help fintech and micro-lending founders build audit-ready ledger systems, automated underwriting pipelines, and bank reconciliation engines. As your fractional CTO, I eliminate book-keeping discrepancies and replace manual loan approvals with deterministic risk workflows. You get compliant financial architecture that satisfies institutional capital partners and scales securely without balance leakage.
01 HIGH-CONCURRENCY PAINS
5 critical founder bottlenecks
I resolve permanently.
Early technical shortcuts create hidden liabilities that compound as order volume scales.
Unbalanced Ledgers & Silent Currency Rounding Errors
Using standard floating-point variables or single-column balances introduces rounding inaccuracies. Internal records drift from reality, making external financial audits painful.
Exhausting Manual Payment Gateway Reconciliation
Disputed fees, processing delays, and unannounced refunds create accounting disorder. Finance teams spend hours cross-referencing CSV files, leaving missing funds unresolved.
Slow, Subjective Loan Underwriting Workflows
Credit managers review borrower PDF bank statements manually. Applicants experience lengthy approval delays and take financing from faster competitors instead.
Scattered Credit Rules Hardcoded in Application Code
Risk limits and interest policies live embedded across frontend forms and backend scripts. Modifying a lending policy requires engineering deployments that risk system stability.
Failed Due Diligence From Banking & Debt Partners
Institutional lenders conduct rigorous technical evaluations before granting credit facilities. Without immutable audit logs, strict ledger separation, and envelope encryption, approvals stall.
02 CORE SPECIALIZATIONS
What I build, audit,
and optimize.
Production systems engineered in Go, PostgreSQL, Redis, and edge event streaming.
Immutable Double-Entry Ledger Engine
I architect append-only financial ledgers where total debits equal total credits across all accounts. Every entry records dual accounting legs with composite identifiers. All money amounts use integer micro-units to prevent rounding errors.
Automated Loan Underwriting Engine
I develop deterministic decision engines that evaluate borrower eligibility within seconds. The engine ingests credit bureau reports, banking cash-flow metrics, and fraud signals against versioned risk policies.
Payment Gateway & Bank Reconciliation Pipeline
I build automated reconciliation services that ingest bank statement files, gateway settlement summaries, and internal ledger logs. The service identifies discrepancies and isolates unsettled transactions for resolution.
Secure KYC, Identity & Device Risk Verification
I engineer customer verification gateways integrating biometric checks, identity document scanning, and fraud heuristics. Sensitive customer information is encrypted using envelope encryption with dedicated keys.
Amortization Schedules & Repayment Waterfall Logic
I implement automated repayment schedule engines that calculate interest, platform fees, and overdue penalties. Incoming payments allocate automatically following strict regulatory waterfall rules.
03 FOUNDER-FRIENDLY MENTAL MODEL
Simple Architecture (For Non-Technical Founders)
Think of your lending platform like a chartered bank with a glass vault.
Every penny entering or leaving the system has a twin record showing origin and destination. Money never appears out of thin air or disappears quietly.
When one account balance drops, another corresponding account balance increases by the exact same amount.
When an applicant requests a loan, our digital verification engine examines their financial background in seconds. If the applicant meets your risk rules, the system prepares the funds for transfer.
Every calculation is permanently saved in an unalterable ledger. This transparency gives bank partners and capital providers total trust in your loan book.
04 FOR YOUR ENGINEERS
Technical blueprint &
system data flows.
Architectural component topology and event boundaries.
flowchart TD
BorrowerClient[Borrower Web & Mobile App] --> EdgeGW[API Gateway - mTLS & HMAC Verification]
subgraph Identity & Compliance Layer
EdgeGW --> KYCSvc[KYC & Ingestion Service - Go]
KYCSvc --> BureauAdapter[Bureau & Bank Statement Adapter]
KYCSvc --> KMSVault[(AWS KMS / Vault - Envelope Encryption)]
end
subgraph Underwriting & Risk Decisioning
EdgeGW --> DecisionEngine[Underwriting Rule Engine - Go]
BureauAdapter --> DecisionEngine
DecisionEngine --> PolicyRepo[(Credit Policy Store - Versioned Rules)]
end
subgraph Core Loan Management & Ledger
DecisionEngine --> LMSSvc[Loan Management Service - Go]
LMSSvc --> LedgerCore[Double-Entry Ledger Core]
LedgerCore --> PostgresLedger[(PostgreSQL 16 - Serializable Isolation)]
end
subgraph Payments & Banking Integration
LMSSvc --> PaymentHub[Payment & Disbursal Gateway Hub]
PaymentHub --> BankPartnerAPI[Banking Partner Disbursal API]
GatewayWebhook[Payment Gateway Webhook] --> WebhookBuffer[Webhook Buffer - Redis]
WebhookBuffer --> PaymentHub
end
subgraph Automated Settlement & Reconciliation
BankStatements[Bank MT940 & Settlement CSV Files] --> ReconWorker[Reconciliation Batch Worker]
ReconWorker --> PostgresLedger
ReconWorker --> ExceptionQueue[Recon Exception Dashboard]
endEnd-to-End Data Flows
The borrower submits verification documents. The identity service encrypts sensitive PII using envelope encryption via AWS KMS, storing only ciphertext in PostgreSQL.
The decision engine pulls credit bureau reports and cash-flow data. An Abstract Syntax Tree evaluator tests applicant parameters against versioned credit policies, issuing an immutable decision record.
When the borrower accepts the contract, the loan management service creates the loan. The ledger records equal balancing entries: Debit LoansReceivable, Credit DisbursalClearingAccount.
Repayments trigger gateway webhooks. The receiver verifies HMAC signatures and logs an idempotency key in Redis. The payment orchestrator executes the waterfall: fees, interest, then principal.
A daily worker fetches bank MT940 statement files and gateway settlement sheets. It matches external transaction identifiers against internal ledger records, sending mismatches to an exception queue.
Storage Engines & Data Partitions
- PostgreSQL 16: Append-only ledger entries operating under serializable transaction isolation. Monetary values use integer data types in minor units (cents or paise).
- Redis 7: Ephemeral idempotency verification keys, distributed locks for concurrent loan modifications, and rate limiters.
- AWS S3 / Cloud Storage: Encrypted regulatory document repository configured with Object Lock retention policies.
- Apache Kafka: Event backbone for loan milestone changes, payment notifications, and real-time risk alerts.
Engineering Design Targets
- Ledger Mathematical Balance: Design target of 100% balance integrity across all accounts on every nightly close.
- Underwriting Decision Latency: Design target under 3 seconds for automated rule evaluation.
- Webhook Idempotency Protection: Design target of zero duplicate balance entries under network retries.
05 VERIFIED PEDIGREE
Former Head of Engineering at Urban Harvest (Engineering Team Grew 15 to 50+)
- Architected enterprise financial ledgers, automated underwriting pipelines, and banking partner integrations.
- Creator of open-source financial libraries, including go-fintech-india on GitHub (github.com/Abeta-dev).
- 12+ years of engineering experience delivering compliant financial architectures.
06 TRANSPARENT PRICING
Single source of truth
pricing & engagements.
Transparent pricing without hidden fees or forced long-term lock-in.
| Engagement Tier | Investment | Scope & Terms |
|---|---|---|
| Architecture Teardown | $1,500 / AED 5,500 / INR 1.25L | 48-hour diagnostic teardown identifying immediate scaling bottlenecks. |
| Architecture Audit | $5,000 | 5-day deep code, database, and cloud audit. 100% credited to any follow-on sprint. |
| Advisory Fractional CTO | $6,000 / month | Strategic steering, architecture roadmaps, and PR reviews. 3-mo min, then 30d notice. |
| Core Fractional CTO | $12,500 / month | Hands-on technical leadership, hiring rubrics, and sprint management. 3-mo min, then 30d notice. |
| CTO + Senior Pod | $35,000 – $48,000 / month | Executive CTO leadership paired with senior systems engineers. 3-mo min, then 30d notice. |
| Build Sprints | From $45,000 | Milestone-based platform development from architecture to live production. |
07 QUESTIONS & ANSWERS
Frequently asked
questions.
Why is double-entry bookkeeping essential for lending platforms?
Single-entry balances cannot trace capital origins. Double-entry ensures every debit has an equal credit, preventing untracked balance drift.
How do you prevent floating-point rounding errors in currency calculations?
We store monetary values as integers in minor currency units, such as cents or paise. We never use floating-point types in financial databases.
How do you test underwriting rule changes safely without risking live loans?
We shadow-run updated rule versions against historical loan applications. We compare decision variance and default rates before promoting rules to production.
What happens if a payment gateway sends the same webhook three times?
Our webhook handlers verify unique event IDs against Redis idempotency locks. The system processes the payment once and ignores duplicates safely.
How do you ensure audit readiness for banking partners and debt funds?
We enforce immutable append-only ledgers, complete transaction lineage, envelope encryption, and real-time reconciliation reports for your auditors.
How quickly can we start a fintech architecture audit?
We begin within 3 business days of booking. You receive a complete 20-page architecture assessment and risk mitigation plan in one business week.
08 GET STARTED
Solidify your architecture
before traffic surges.
Book a direct 20-minute video session with software architect Umesh Gupta. Response promise: same business day (IST).