How Octopus Energy Tariffs Work

Every rate you see here is read from a Postgres database of Octopus's published tariffs, which a separate process keeps filled. It holds unit rates and standing charges, including VAT, for every supported tariff in all 14 regions of Great Britain, going back to 2018 — which is what makes the history charts and the price cap comparison possible.

Pages are built ahead of time and regenerated in the background every fifteen minutes, so a page never waits on a database read. Half-hourly tariffs like Agile change within that window; a flat tariff may sit unchanged for months. The fifteen-minute cycle is how often we look, not how often the price moves.

Your browser sends the postcode transiently in a POST request body. It never enters this site's browser-visible URL, storage, cache, logs, or response. To use Octopus's authoritative mapping, the site then sends a transient, no-store request to Octopus. That upstream request uses the compact postcode in its URL and is discarded after the lookup finishes. Only the resulting canonical region may be remembered locally for tariff tools. Everything else is already in the database before you arrive.

The private usage, data-gap, and comparison tools work differently from the public tariff pages. The browser connects directly to Octopus Energy over HTTPS, and this site never receives your API key, account number, MPAN, meter serial numbers, account payload, or consumption payload.

The current browser session is the default lifetime for that connection. You can explicitly choose Remember on this device for a durable browser copy, and Forget account clears both connection stores. No consumption payload is stored.

When you ask for a tariff comparison, the same browser separately requests the same-origin site for published comparison data using region and London date bounds only. If the switchable set does not contain the exact current product, the browser obtains that tariff's published rates directly from Octopus without sending credentials with the public-rate request. Baseload and cost outputs remain estimates, not bills, quotes, or device readings, and they disclose the standing-charge scalar plus excluded discounts, dispatch overrides, exit fees, export credits, and billing adjustments.

Custom tariff definitions are structured daily half-hour bands held only in local storage. The comparison uses one shared set of seven to 28 complete London days for every ranked published and custom tariff; disconnected results use an illustrative synthetic profile and are not a forecast or switching quote.

Understanding Each Tariff

Great Britain is divided into 14 electricity distribution regions, each identified by a letter (A-P, excluding I and O). Your postcode determines which region you're in through the Grid Supply Point (GSP) system.

Prices can vary between regions due to differences in local distribution costs, network constraints, and wholesale market conditions.

Public rate alerts

The optional alert form sends an email address and a public regional rate condition through a protected same-origin implementation detail. Signup uses double opt-in; only confirmed alerts are evaluated against published rates, and every email has an unsubscribe link. Account credentials and private usage never enter this flow.

Occasionally, wholesale electricity prices can go negative during periods of very high renewable generation and low demand. When this happens, Agile customers are actually paid to use electricity during those periods.

Negative prices are most common during:

• Sunny, windy days with high renewable generation
• Low-demand periods (overnight, weekends, holidays)
• Spring and autumn when heating and cooling demand is lower

Frequently Asked Questions

Important Information