Processing

Estimate and Set EVM Gas Fees

Under-priced EVM transactions stall; over-priced ones waste money. This guide reads a fee estimate, sets EIP-1559 fields, and simulates before broadcast so a fee shortfall never strands your transaction. Applies to eth and other EVM chains.

Antes de começar

The unsigned EVM transaction you intend to send.
An API key with C2 access for build and simulate.

1Get a fee estimate from build

Build the transaction; the response carries a fee estimate you use to set maxFeePerGas and maxPriorityFeePerGas.

curl -X POST https://api.1st-node.com/v1/tx/eth/build \
  -H "Authorization: Bearer sk_live_..." \
  -d '{"from":"0x8f2c...","to":"0x7a1d...","amount":"50000000000000000"}'
> {"raw":"0x02f8...","max_fee_per_gas":"32000000000",
>  "max_priority_fee_per_gas":"1500000000","gas_limit":"21000"}

2Simulate at the chosen fee

Simulate the raw transaction. A fee-shortfall or revert surfaces here before you sign, so raise maxFeePerGas or fix inputs.

curl -X POST https://api.1st-node.com/v1/tx/eth/simulate \
  -H "Authorization: Bearer sk_live_..." \
  -d '{"raw":"0x02f8..."}'
> {"success":true,"gas_used":"21000","revert_reason":null}

3Sign and broadcast

Sign where you keep keys, then broadcast. The response returns the transaction hash to track for inclusion.

Perguntas frequentes

How do I avoid a stuck EVM transaction?

Set maxFeePerGas from the build estimate with headroom, then simulate. If the simulation flags a fee shortfall, raise the fee before signing.

Do you sign the transaction for me?

No by default. Build and simulate are non-custodial — you sign where you keep keys. Custodial signing is a separate opt-in primitive.

Continue lendo

ethereum-api build-sign-and-broadcast-a-transaction /pricing

Recarregue, pegue a chave e publique.

Autoatendimento. Pague em cripto ou cartão. Medido por créditos: primitivas pesadas custam mais, as simples são baratas.

Obter chave de API