1---2title: Understanding fuel3audience: user4---56# Understanding fuel78Your relay is free until it passes a monthly allowance. Past that, use is paid for in sats. Anyone can top up a relay by zapping it.910## What is measured1112Four resource lines are measured and priced in fuel. Each mirrors a major line13on the hosting bill, while provider request charges and other deployment costs14remain outside the tenant meter.1516| Measured | Free each month |17|---|---|18| Events stored | 100 MB |19| Files stored | 1 GB |20| Time awake | 100 hours |21| Rows written | 250,000 |2223Traffic bytes in and out have no fuel price. The console shows them so you can24see what the relay does. The host still pays any provider request or platform25charge attached to moving or storing those bytes.2627**Time awake** estimates how long the relay is in memory from its entrypoints.28It can sleep between messages, while alarms and scheduled jobs wake it even29when no client is connected. The meter adds ten seconds after a wake, then30the gap between entrypoints capped at ten seconds. It does not time a whole31long-running job. Jobs on the Sync tab, pulls, backfills, rebroadcasts, Git32requests and site work all wake the relay. The host's actual duration cost33can be higher or lower than this estimate.3435Dumps, the JSONL files the Data tab can write on a schedule, live next to uploaded files and count as files stored. What each job and dump does is in [Data and names](04-data-and-names.md).3637**Rows written** is database work. A note costs a few rows. Reactions and other small events cost about the same.3839The newer doors use these same meters. NIP-5A files mirrored into the relay are40part of **Files stored**. Git repositories store compressed chunks, refs and41receipts in the relay's SQLite database, so they are part of **Events stored**.42A site cache miss, site mirror,43Git clone or Git push also wakes the relay and can write events or accounting44rows. Marmot KeyPackages and encrypted group envelopes are ordinary stored45events, so they use **Events stored** and **Rows written**. HTTP request and46response bytes are shown as traffic for your information, but traffic has no47fuel price. There is no separate tenant charge for a site, Marmot or GRASP48request. There is no separate tenant charge for Git requests.4950GRASP keeps bounded object, decoded-pack, retained-history, ref and repository51limits. It has no transaction-count ceiling, but it still bounds52its object, byte and receipt work. These limits share the existing storage allowances rather than adding a53new one. Signed events wait for their required Git objects before publication.54Deleting a ref or expiring metadata does not reclaim immutable Git history;55those bytes remain in SQLite until the relay is deleted. See56[GRASP-01 Git hosting](22-grasp-01-git-hosting.md) for the full limits.5758Git storage includes transaction receipts and retained bookkeeping as well as59objects. It is not a fixed reservation per repository: the total grows with60its history, including ref-only updates. The Health tab shows the combined61storage total. The `gitstorage` management method gives owners a bounded62backend-specific breakdown without authorizing deletion.6364## Prices past the allowance6566| Measured | Price |67|---|---|68| Events stored | 400 sats per gigabyte-month |69| Files stored | 30 sats per gigabyte-month |70| Time awake | 11 sats per hour |71| Rows written | 2,000 sats per million |7273Storage is charged daily, in proportion to how far over the allowance the relay is. Time and rows are charged as they happen. The current prices are always on the relay's Fuel section and on the bind.ws front page.7475## Topping up7677On your relay's page, enter an amount and click **Zap to top up**. Your extension signs a zap request, and the page shows a lightning invoice. Pay it from any lightning wallet. The receipt lands on your relay and credits it within a minute.7879You do not have to be the owner. Anyone can zap any relay.8081## Running out8283When a relay is over an allowance with no balance, it goes read-only. Clients84get a clear message when they try to publish. Nothing is deleted. Ordinary85reading, searching and syncing keep working, while GRASP Git hosting refuses86requests until the balance or allowance permits it. Remote site fetches and87mirroring also stop; already stored site files remain readable under the88relay's read rule. A sufficient top-up lifts the fuel restriction.8990## Seeing the numbers9192`https://<name>.bind.ws/fuel` is public and returns the meters, allowances, prices, balance and recent zaps as JSON. The Health tab shows the same numbers.9394The meters are the relay's view of usage, not a complete provider invoice.95Cloudflare storage and database request charges can include R2 operations, KV96operations and SQLite work that does not map one-for-one to stored bytes or97the rows counted by the relay. The host checks those provider bills separately;98the four fuel lines are the transparent budget shown to you.