# Are diesel prices going down?

The JSON comparison includes `tankLitres` (60) and `tankCostChangeAud`, the signed change in Australian dollars for a full tank of that assumed size. A negative value means a lower estimated fill cost; a positive value means a higher cost. The estimate uses the statewide average, not a station quote.

The `history` array contains the last seven Sydney calendar days, oldest first, with the latest saved statewide average in cents per litre for each day. An average of null means that day's snapshot is unavailable. Today's snapshot updates during the day.

> A live NSW regular diesel price check, with a statewide direction answer and the cheapest listed stations near supplied coordinates.

The answer compares the latest NSW-wide average of listed regular diesel (FuelCheck code DL) prices with the previous Sydney calendar day's final average. "Yes" means today's average is strictly lower. "No" means it is equal or higher. A null answer means the comparison is not yet available. Prices are in cents per litre and refresh about hourly.

Nearby stations require both `lat` and `lon` query parameters in decimal degrees. The response lists up to five distinct stations within 10 km, sorted by price then straight-line distance. Without coordinates, `nearby` is null. No location is inferred from an IP address.

## Live data

- [JSON summary](https://diesel-direction.askinner.workers.dev/api/summary): Current answer, averages, timestamp, source, and optional nearby stations. GET without parameters for the statewide answer; add `?lat=-33.86&lon=151.2` as a coordinate example. Invalid or incomplete coordinates return HTTP 400.
- [Page in Markdown](https://diesel-direction.askinner.workers.dev/index.md): Concise description of the site's calculations and location behavior.

## Optional

- [Interactive website](https://diesel-direction.askinner.workers.dev/): Human-facing page that asks the browser for location when the visitor taps the location button.
- [NSW FuelCheck data](https://data.nsw.gov.au/data/dataset/fuel-check): Source dataset and attribution.