eth_feeHistory

eth_feeHistory returns historical base fees, gas-used ratios, and priority-fee percentiles for a window of recent OP Mainnet blocks, all denominated in ETH wei. OP Mainnet implements EIP-1559, so this method is the foundation for building type-2 fee strategies on the rollup: sample recent percentile data and derive sensible maxFeePerGas and maxPriorityFeePerGas values. Call https://optimism.therpc.io/YOUR_API_KEY (chain ID 10, 0xa) with a block count, a newest block, and the percentiles you want.

Use cases

Build an OP Mainnet fee estimator that derives maxFeePerGas and maxPriorityFeePerGas from recent percentile data.
Render a gas-fee trend chart in a wallet or in an explorer alongside optimistic.etherscan.io.
Detect L2 congestion by tracking gasUsedRatio across recent blocks — values near 1 mean the sequencer is filling blocks.
Implement MEV-aware tip strategies by analysing the per-block reward percentiles to set a competitive priority fee.

Parameters

#	الاسم	النوع	مطلوب	الوصف
1	`blockCount`	string \| number	نعم	Number of blocks to include in the history window. Most providers cap this at 1024.
2	`newestBlock`	string	نعم	The most recent block to include in the window.الافتراضي: `latest`
3	`rewardPercentiles`	number[]	لا	Array of percentile values (0–100) at which to sample priority fees from each block. Pass an empty array to omit reward data.

Response

النوع	الوصف
object	Object with: `oldestBlock` (hex, starting block of the window), `baseFeePerGas` (array of hex wei — one per block plus the next predicted value), `gasUsedRatio` (array of floats 0–1 per block), `reward` (array of arrays — per-block percentile priority fees in hex wei; only present when `rewardPercen

Example request

1curl https://optimism.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_feeHistory",
7    "params": [
8        4,
9        "latest",
10        [
11          25,
12          50,
13          75
14        ]
15      ],
16    "id": 1
17  }'

Try it live in the Optimism playground.

Errors & troubleshooting

الكود	الرسالة	السبب
`-32602`	`invalid argument`	blockCount is 0, out of range, or rewardPercentiles contains values outside 0–100.
`-32000`	`block not found`	`newestBlock` references a block that does not exist on this node.

Common pitfalls

The baseFeePerGas array has one extra element: the last entry is the node's prediction for the next OP Mainnet block, not a confirmed value — don't treat it as historical.
This covers L2 base fees only; the L1 data fee component of an OP Mainnet transaction's total cost is not reflected here, so a fee built from this alone will undercount the real ETH spend.
Large blockCount values produce large responses (most providers cap at 1024); cap at 100–200 blocks per call and paginate to keep payloads manageable.

Supported networks

Mainnet — Chain ID: 10
Sepolia — Chain ID: 11155420

#	الاسم	النوع	مطلوب	الوصف
1	`blockCount`	string \| number	نعم	Number of blocks to include in the history window. Most providers cap this at 1024.
2	`newestBlock`	string	نعم	The most recent block to include in the window.الافتراضي: `latest`
3	`rewardPercentiles`	number[]	لا	Array of percentile values (0–100) at which to sample priority fees from each block. Pass an empty array to omit reward data.

Response

النوع	الوصف
object	Object with: `oldestBlock` (hex, starting block of the window), `baseFeePerGas` (array of hex wei — one per block plus the next predicted value), `gasUsedRatio` (array of floats 0–1 per block), `reward` (array of arrays — per-block percentile priority fees in hex wei; only present when `rewardPercen

Example request

1curl https://optimism.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_feeHistory",
7    "params": [
8        4,
9        "latest",
10        [
11          25,
12          50,
13          75
14        ]
15      ],
16    "id": 1
17  }'

الكود

الرسالة

السبب

-32602

invalid argument

blockCount is 0, out of range, or rewardPercentiles contains values outside 0–100.

-32000

block not found

`newestBlock` references a block that does not exist on this node.

Common pitfalls

The baseFeePerGas array has one extra element: the last entry is the node's prediction for the next OP Mainnet block, not a confirmed value — don't treat it as historical.

This covers L2 base fees only; the L1 data fee component of an OP Mainnet transaction's total cost is not reflected here, so a fee built from this alone will undercount the real ETH spend.

Large blockCount values produce large responses (most providers cap at 1024); cap at 100–200 blocks per call and paginate to keep payloads manageable.

eth_feeHistory

Use cases

Parameters

Response

Example request

Errors & troubleshooting

Common pitfalls

Supported networks

See also

هل أنت مستعد لاستدعاء هذا في الإنتاج؟

eth_feeHistory

Use cases

Parameters

Response

Example request

Errors & troubleshooting

Common pitfalls

Supported networks

See also