Actors
Identify customers, operators, reviewers, administrators, finance teams, partners, and automated services together with what each may view or change.
Start a project ↗Fintech Engineering / Published 2026-09-06
How to Plan a Custom Fintech Platform Before Writing Code
A system-design checklist for financial workflows, permissions, data sources, auditability, reconciliation, integrations, and operational ownership.
01 / Direct answer
Model the financial workflow before the software architecture.
Before choosing databases, frameworks, or cloud services, document the actors, financial events, authoritative data, approval points, exceptions, reconciliation rules, and records the platform must preserve.
Financial events
Define deposits, withdrawals, payments, fees, adjustments, balances, approvals, settlements, reversals, and other domain events relevant to the product.
Authoritative data
State which system owns each important value and how conflicts between providers, internal records, and user-facing views are reconciled.
Audit trail
Decide which actions and state changes must be traceable later for operations, investigation, dispute handling, or compliance support.
02 / Integrations
External dependencies need explicit failure behavior.
Financial platforms often depend on providers outside the product team's control. Timeouts, duplicated requests, delayed callbacks, partial failures, and inconsistent provider state must be planned rather than treated as rare exceptions.
Idempotency
Repeated requests should not create duplicated financial actions when a client or network retries after an uncertain response.
Reconciliation
Build a way to compare internal records against provider or settlement records and surface mismatches for review.
Retry policy
Retry only operations that are safe to repeat and use clear limits, backoff, and dead-letter or manual-review paths where appropriate.
Provider observability
Track latency, failures, rejected operations, schema changes, and dependency health separately from ordinary application errors.
03 / Delivery
Release around controlled business slices.
A useful first release should complete one coherent financial workflow with correct permissions, records, failure handling, and operational support rather than expose many unfinished modules.
Acceptance criteria
Define observable correctness conditions for calculations, state transitions, permissions, exports, and integrations.
Operational runbook
Document what the team should do when a provider is unavailable, data does not reconcile, or a customer reports an unexpected state.
Security review
Review secrets, authentication, authorization, logging, data exposure, and infrastructure access before production release.
Regulatory ownership
Software implementation does not replace jurisdiction-specific legal or regulatory analysis. The business must identify the obligations that apply to its actual product and market.
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