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EVM Next Base Fee Bound
x402
EVM Next Base Fee Bound is a paid API for AI agents from api.delx.ai, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Computes the lower and upper bound (in wei) of the next EVM block's base fee given the current base fee and a maximum change fraction.
Price / call$0.001
Success—
StatusUnknown
How this service works
EVM Next Base Fee Bound: EVM Next Base Fee Bound calculates upper and lower next-block base-fee bounds from bounded caller-supplied values without an external provider. Call EVM Next Base Fee Bound before signing, submitting, replacing, or accepting an EVM/Base transaction assembled from caller-owned data. Returns normalized transaction evidence, calculated budget or shape findings, and a fail-closed preflight status for EVM Next Base Fee Bound as versioned deterministic JSON. Price: $0.001 USD…
Output
Returns a JSON object with lower_wei and upper_wei representing the minimum and maximum possible base fee for the next EVM block, along with operation metadata, schema identifier, status, and an evidence block confirming no data retention and no external calls were made.
Example use cases
Gas budget preflight for EVM transaction
“Before I submit this Ethereum transaction, calculate the lower and upper base fee bounds for the next block — the current base fee is 2000000000 wei and the max change fraction is 0.125.”
Automated gas price ceiling enforcement
“My agent needs to know if the next block's base fee could exceed 1500000000 wei — compute the upper bound given a current base fee of 1300000000 wei and a max change fraction of 0.125 so I can decide whether to submit now or wait.”
Fee estimation for batch transaction scheduling
“I'm scheduling a batch of on-chain transactions and need the expected base fee range for the next block. Current base fee is 900000000 wei and max change fraction is 0.125 — what are the min and max I should plan for?”
Technical details
Endpoint
POSThttps://api.delx.ai/api/v1/x402/evm-next-base-fee-boundWhen to prefer
Use this endpoint when an AI agent needs a deterministic, auditable calculation of the next EVM block's base fee range without making any external RPC calls itself — particularly during transaction preflight, gas budgeting, or fee ceiling checks. Prefer this over on-chain RPC lookups when you already have the current base fee and want a fast, stateless, in-memory computation with a verifiable evidence trail.
Side effects
- Missing or malformed current_base_fee_wei (non-numeric string) may cause a validation error
- maximum_change_fraction outside plausible EVM range (e.g. negative or >1) may produce unexpected bounds
- Incorrect units (e.g. gwei instead of wei) will silently produce wrong bounds without an error
- Payment failure or insufficient USDC balance results in a 402 rejection before execution
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| current_base_fee_wei | string | Current Base Fee Wei supplied to EVM Next Base Fee Bound; used only for this bounded calculation and processed in memory without retention. |
| maximum_change_fraction | number | Maximum Change Fraction supplied to EVM Next Base Fee Bound; used only for this bounded calculation and processed in memory without retention. |
Output
Schema · Response
{
"type": "json",
"example": {
"result": {
"lower_wei": "875000000",
"upper_wei": "1125000000"
},
"schema": "delx/util-evm-next-base-fee-bound/v1",
"status": "pass",
"evidence": {
"retained": false,
"input_sha256": "bd788e10cae66dfcf807641601d7bf74d3bd4f11c95ecfe6477c865c191f130f",
"external_calls": 0
},
"operation": "evm_preflight:evm_next_base_fee_bound"
}
}Tags
x402
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