How historical exchange rates work

How Narwhal returns real observation dates, sparse currencies, and bounded FX history pages.

Narwhal mascot studying a timeline of historical exchange-rate observations

Dates are real observations

Weekend and holiday rows are omitted when no observation exists. A returned date can contain only part of the requested currency list.

Pages count dates

The limit counts observation dates, not individual currency records. A page never splits one date across two responses.

Keep the filters with the cursor

Reuse the same base, currencies, start date, and end date with each next_cursor. Changing a filter makes the cursor invalid.

Sources and references

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