DaTom InsightsArticles by Dawid Tomkalski on software architecture for SaaS: ledgers, payments, AWS and technical leadership.https://datom.com.au/insights/en-auWhat a fractional architect does in the first 90 dayshttps://datom.com.au/insights/fractional-architect-first-90-days/https://datom.com.au/insights/fractional-architect-first-90-days/How the first three months with a fractional architect or CTO run: learning the system, written findings and priorities, then a steady rhythm of decisions and reviews.Fri, 02 Oct 2026 00:00:00 GMTFractional CTO and tech leadArchitecture reviewinfo@datom.com.au (Dawid Tomkalski)One payment interface, many gateways and a separate PCI vaulthttps://datom.com.au/insights/payment-interface-pci-vault-multiple-gateways/https://datom.com.au/insights/payment-interface-pci-vault-multiple-gateways/How to support several payment gateways behind one interface while tokenised card data stays in a separate PCI vault, and what that does to your PCI DSS scope.Fri, 02 Oct 2026 00:00:00 GMTPayments integrationinfo@datom.com.au (Dawid Tomkalski)Designing a trust accounting ledger that can’t double-debithttps://datom.com.au/insights/trust-accounting-ledger-double-debit/https://datom.com.au/insights/trust-accounting-ledger-double-debit/How I design trust accounting ledgers: double-entry, an append-only journal, idempotency keys enforced by the database, reversals, periods and reconciliation.Fri, 02 Oct 2026 00:00:00 GMTTrust accounting softwareinfo@datom.com.au (Dawid Tomkalski)