Exchange rates

An exchange rate converts between currencies when a customer is billed in one and you report in another. Kontier syncs rates, lets you override them, and pins the rate an invoice used so the number never moves afterwards.

That pinning is the important part. A finalised invoice is a legal record; if it were re-converted at today's rate, last quarter's revenue would change every morning.

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Snapshots

Rates are stored as dated snapshots. A snapshot is every rate as of a given date, so a conversion is always "this pair, on that day", not "this pair, now".

Check sync-status before investigating a "wrong" conversion. A stale sync explains more FX surprises than a wrong rate does.

Overrides

POST /v1/fx/overrides sets a rate yourself, for a pair and a period. Two reasons to reach for one:

• A contractual rate. A customer negotiated a fixed EUR/CHF rate for the year, and the contract wins over the market.
• A correction. The synced rate was wrong and the invoices need to be right.

An override takes precedence over the synced snapshot for its pair and window. Because it changes money, treat adding one as a deliberate act rather than a configuration tweak.

Pinning at finalisation

While an invoice is a draft, conversions are indicative and follow the current rate. When it is finalised, the rate is written down with the document and never recalculated.

So an invoice finalised on 3 March at 0.9520 stays at 0.9520 forever, even if you regenerate the PDF a year later.

The same logic governs credit notes: a note against an invoice uses the invoice's pinned rate, not today's, so a reversal is exactly equal and opposite.

Dashboard and API names

Where exchange rates go next

1. Prices are per currency. FX converts for reporting; it does not invent a price. A customer billed in CHF needs a CHF price.
2. Invoices record the rate they used, per line.
3. Analytics converts historical figures using the rate each invoice was pinned at, which is why past periods stay stable.

Reference