# Delx EVM EIP-1559 Fee Check

> Delx EVM EIP-1559 Fee Check 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).

Validates EIP-1559 transaction fee parameters (gas limit, max fee per gas, max priority fee per gas) and computes ceiling values for EVM preflight checks.

## Facts

- Endpoint: POST https://api.delx.ai/api/v1/x402/evm-eip1559-fee-check
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/delx-evm-eip-1559-fee-check-0c194944
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LsU7JUebNRLAIT9mP-MFF

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability delx-evm-eip-1559-fee-check-0c194944 -d '<json body>'
```

Example prompt: Before I submit this Ethereum transaction, check if my EIP-1559 fee parameters are valid: gas limit is 21000, max fee per gas is 2000000000000 wei, and max priority fee per gas is 100000000000 wei — tell me the fee ceiling and whether the caps are properly ordered.

## When to prefer this

Use this endpoint when you need a fast, cheap, privacy-preserving preflight validation of EIP-1559 fee parameters before submitting an EVM transaction. Prefer this over on-chain or RPC-based fee checks when you want deterministic, in-memory computation with no external blockchain calls and a guaranteed evidence trail. Ideal for AI agents building or reviewing EVM transactions programmatically.

## Known failure modes

- Invalid or non-numeric wei string values may cause parsing errors
- Gas limit of zero or negative may produce invalid calculations
- Missing required fields returns a validation error
- Malformed JSON request body returns a 400-level error
- max_priority_fee_per_gas_wei exceeding max_fee_per_gas_wei results in fee_caps_ordered=false (not a hard error, but a failed check)

## How this service works

EVM Eip1559 Fee Check: EVM Eip1559 Fee Check checks dynamic-fee caps and calculates the worst-case transaction fee from bounded caller-supplied values without an external provider. Call EVM Eip1559 Fee Check 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 Eip1559 Fee Check as versioned deterministic JSON. Price: $0…

## Output

Returns a JSON object with: fee_ceiling_wei (maximum possible transaction fee in wei), priority_fee_ceiling_wei (maximum priority fee in wei), fee_caps_ordered (boolean indicating whether max_fee >= max_priority_fee), and an overall status ('pass' or 'fail'). Also includes evidence metadata confirming no external calls were made and inputs were not retained.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "gas_limit": {
   "type": "integer",
   "description": "Gas Limit supplied to EVM Eip1559 Fee Check; used only for this bounded calculation and processed in memory without retention."
  },
  "max_fee_per_gas_wei": {
   "type": "string",
   "maxLength": 8192,
   "description": "Max Fee Per Gas Wei supplied to EVM Eip1559 Fee Check; used only for this bounded calculation and processed in memory without retention."
  },
  "max_priority_fee_per_gas_wei": {
   "type": "string",
   "maxLength": 8192,
   "description": "Max Priority Fee Per Gas Wei supplied to EVM Eip1559 Fee Check; used only for this bounded calculation and processed in memory without retention."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": {
   "fee_ceiling_wei": "42000000000000",
   "fee_caps_ordered": true,
   "priority_fee_ceiling_wei": "2100000000000"
  },
  "schema": "delx/util-evm-eip1559-fee-check/v1",
  "status": "pass",
  "evidence": {
   "retained": false,
   "input_sha256": "09e6859a0243cf6df6f99d660a7735e0bfb2893802645cebf1d03fa659f21a65",
   "external_calls": 0
  },
  "operation": "evm_preflight:evm_eip1559_fee_check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/delx-evm-eip-1559-fee-check-0c194944/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.delx.ai](https://www.zero.xyz/host/api.delx.ai/llms.txt)