gasweek-js

gasweek-js

when is ethereum cheapest? the base fee by hour of day over the last week, from a public json-rpc endpoint, in the browser or in node. zero dependencies, no keys. the typescript twin of gasweek, same pages, same interpolation, same percentiles.

install

npm install gasweek

or straight from the repository: npm install github:alinaschanz/gasweek-js.

use

import { gasweek, table } from "gasweek";

const { rows, summary } = await gasweek({ hours: 168, tz: 2 }); // a week, hour bins in berlin summer time
console.log(summary.median, summary.cheapestHour, summary.priciestHour);
console.log(table(rows, 2));

in a browser it is the same import from a module script (the public endpoints answer cross-origin requests); pass your own node first with rpc: ["https://your.node", ...RPCS].

the pieces are exported on their own: Rpc (a list of endpoints tried in order, the one that answered goes first next time), fetchFees(rpc, blocks) (rows with interpolated timestamps), summarize(rows, tz) (min, p25, median, p75, p90, max, blob median, medians by hour and by weekday, cheapest and priciest hour), percentile, bucket, table.

how it works

• eth_feeHistory returns the base fee per block, the gas used ratio and, since cancun, the blob base fee. it does not return timestamps.
• so one block header per 1024-block page is fetched and the blocks in between are interpolated; post-merge blocks are 12 s apart except for missed slots, which keeps the error inside a page under a minute.
• percentiles are order statistics with linear interpolation; hour and weekday bins follow tz (an offset in hours, no dst logic on purpose).
• a full week is 50,400 blocks, 50 pages, four in flight at once; a minute or two on a public node.
• endpoints: publicnode, drpc, mevblocker, tenderly, blastapi, in that order.

development

npm ci
npm test        # tsc, then node --test on the compiled output

see also

• gasweek, the python original, with the daily dataset and the svg chart
• onchain-notes, the daily card

license

mit.