API reference, Chain & reference
Gas tracker
- Elysium: Every Elysium block's base fee, gas used and tips over 1h to 7d, with stats and the latest block.
- HyperEVM: Every HyperEVM block's base fee, gas used and tips over 1h to 7d, with stats and the latest block.
- Not on HyperCore: HyperCore has no gas: its actions pay fixed exchange fees (POST /info userFees)
GET https://api.femtos.xyz/v1/gas
Parameters
| Param | In | Example or values | Meaning |
|---|---|---|---|
layer | query | elysium (Elysium); hyperevm (HyperEVM) | EVM layer |
window | query | (empty), 1h, 6h, 24h, 7d | Window ending now: 1h, 6h, 24h or 7d |
resolution | query | (empty), block, 10s, 1m, 5m, 15m, 1h | block, 10s, 1m, 5m, 15m or 1h; default auto (every block up to 25000 per series) |
Example
Elysium
curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/gas?layer=elysium&window=1h&resolution=5m"HyperEVM
curl -H "Authorization: Bearer $FEMTOS_KEY" "https://api.femtos.xyz/v1/gas?layer=hyperevm&window=1h&resolution=5m"Key: Authorization: Bearer $FEMTOS_KEY. Get a free key, or with no browser through agent onboarding.
Response fields
| Field | Type | Meaning |
|---|---|---|
series[] | object | HyperEVM: small then big blocks; Elysium: one series: {kind, resolution, blocks, stats, latest, points} |
series[].kind | small | big | block | small / big: HyperEVM's two block kinds, each with its own base fee and mempool (small: 3M gas, about one a second; big: 30M gas, about one a minute; a gas limit above 10M is big); block: Elysium's one kind |
series[].resolution | block | 10s | 1m | 5m | 15m | 1h | block: one point per block; else buckets of that span (UTC-aligned) |
series[].stats | object | The window at block precision: {baseFee, tipP50, tipP90, gasUsed, txs, utilization} |
series[].latest | object | null | The newest block of this kind (in or before the window): {block, time, kind, baseFee, gasUsed, gasLimit, txs, tipP50, tipP90} |
series[].points | object | The series as columns: index i of each array is one point, oldest first: {time, block, blocks, baseFee, baseFeeMin, baseFeeMax, gasUsed, gasLimit, txs, tipP50, tipP90} |
head | object | null | The newest block the tracker holds; null before the first: {block, time} |
tipsFrom | int | null | Oldest block from which every block has its tips (the history's are read from the node, newest first, after a restart); null before the first |
Related: Chain & reference
- Freshness GET /v1/status Elysium, HyperCore, HyperEVM
Head and lag of each layer, measured now. - Freshness stream WS status Elysium, HyperCore, HyperEVM
The GET /v1/status answer (head and lag of each layer, live feeds), pushed whole on subscribe and at most once a second when it changes. - Blocks stream WS elysium.blocks | hyperevm.blocks Elysium, HyperEVM
Each new HyperEVM block header, small and big blocks, from our node. - Gas stream WS elysium.gas | hyperevm.gas Elysium, HyperEVM
Each new HyperEVM block's base fee, gas used and tips, from our node; the history is GET /v1/gas. - Block GET /v1/blocks/{number} Elysium, HyperEVM
One HyperEVM block and every transaction in it: who called what, swaps, gas and fees. - Transaction GET /v1/tx/{hash} Elysium, HyperEVM
One transaction: status, gas, decoded transfers, swaps and liquidity, bridge legs and journey. - Elysium RPC POST /v1/elysium/rpc Elysium
Free public Elysium mainnet RPC by Femtos (chain 99901), no key, read only (no transaction sending), for wallets and dapps, not for indexing (use the Femtos API for history): per IP 5 requests a second and 60 a minute, batches of 5, eth_getLogs over 1,000 blocks at most, state of the last 128 blocks only. - Stream stats WS stats HyperCore
Our HyperCore stream health, once a second. - Check your key GET /v1/whoami Elysium, HyperCore, HyperEVM
Answers the name your key is registered under, its tier, billing state and the limits in force. - OpenAPI document GET /v1/openapi.json Elysium, HyperCore, HyperEVM
The OpenAPI 3.1 contract of every REST call, public.
More
- This page as Markdown
- The whole API reference
- What Elysium serves
- What HyperEVM serves
- The whole API in one Markdown file
- OpenAPI 3.1 document
Agent guide (agents.md)llms.txtOpenAPIMCP serverGet an API keyChangelog