How to Judge Whether a Rate Feed Is Fresh
Defines fresh, stale and unavailable rate data, timestamps, validation and transparent source-level status.
A rate board can display a timestamp and still contain a source that stopped updating. To judge freshness, it helps to separate three moments: when the exchange published or exposed a quote, when the comparison site retrieved it, and when the visitor viewed the page. Those times may not be identical.
What a timestamp should mean
A useful timestamp should describe the last successful data retrieval, not simply the time the page was rendered. If a scheduled task runs but the source returns an error, updating the displayed time as though new data arrived would mislead visitors.
Fresh, stale and unavailable
- Fresh: the source returned valid data within the site's stated freshness window.
- Stale: the latest usable data exists, but it is older than that window.
- Unavailable: there is no usable quote to show.
The exact time window should be documented and chosen according to the source's update behaviour. A cached value should not silently appear as a live quote.
Validate the data before displaying it
A feed can return an empty response, an unexpected format, a zero value or a price outside the range the application expects. The site should validate required fields and numeric values before updating its stored snapshot. If validation fails, preserve the last known good data only if it is clearly labelled stale.
Show source-level status
One source can fail while other sources continue to respond. Where possible, show status and last-success time for each source instead of giving the entire board one timestamp that hides partial failures. Do not describe an exchange as currently available if the application has not received a usable response from it.
What readers should do
Use the comparison as a shortlist, open the original source, refresh the quote and check the order limits and fees. If the source's displayed price differs from the comparison, the original service's current order screen should take precedence.
Maintenance note for site operators
Monitor fetch errors, response changes and unusual values. Keep logs free of passwords, API secrets and personal payment information. A small status page or clear source note can help readers understand temporary gaps without implying that missing data is a bargain.