Build vs. Buy

Building your own multi-currency ledger, versus licensing one

Both are legitimate paths. The trade-offs are concrete, not philosophical — they show up in specific engineering decisions that are expensive to reverse later.

Where the two paths actually diverge

Decision	Building in-house	Licensing infrastructure
Currency precision	Every service that touches money must independently get minor-unit exponents right per ISO 4217 — yen, Kuwaiti dinar, and everything between.	Handled once, at the ledger layer, for every currency you'll ever add.
Cross-currency entries	Needs a deliberate FX position account design decided early — retrofitting it after entries exist is a migration.	Built into how an entry is structured from day one.
Correcting mistakes	Requires a team-wide discipline never to edit or delete a posted entry — easy to state, hard to enforce under deadline pressure.	Enforced by the ledger itself; there is no edit or delete path to bypass.
Multi-entity, multi-jurisdiction	A second entity, a second currency, or a second reporting framework often means forking the chart of accounts.	One installation is designed to serve entities in different jurisdictions without a fork.
Time to first entity live	Months to years, depending on team size and how much of the above is already solved.	Bounded by integration work, not ledger design work.
Ongoing ownership	Your team owns every future currency, jurisdiction, and standards change (ISO 20022, IFRS updates) indefinitely.	Those changes are the vendor's ongoing responsibility.

When building in-house is the right call

If your institution operates in a single currency, a single jurisdiction, and has no near-term plan to expand either, the case for building is genuinely strong — you avoid a vendor relationship for a problem that isn't multi-dimensional yet.

When licensing is the right call

The case for licensing gets stronger with every additional currency and jurisdiction, because each one multiplies the surface area a homegrown system has to get right — and keep right, as standards and regulations change under it.