# Tollex Chain Simulate

> Tollex Chain Simulate is a paid API for AI agents from api.tollex.org, paid per call via x402, $0.0079/call, status unknown (last checked 2026-10-11).

Simulates an EVM transaction (call or value transfer) against a live or forked chain and returns the execution result without broadcasting

## Facts

- Endpoint: POST https://api.tollex.org/tools/chain_simulate?utm_source=zero.xyz
- Price: $0.0079/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tollex-chain-simulate-be6e142d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sLC7KAiBI4wHoVEmriyFL

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 tollex-chain-simulate-be6e142d -d '<json body>'
```

Example prompt: Simulate this EVM transaction for me — from address 0xAbCd...1234, calling contract 0x7890...EF01 with calldata 0xa9059cbb000000...0064 and zero ETH value — and tell me if it will revert or succeed.

## When to prefer this

Choose this endpoint when you need to dry-run an EVM transaction before committing it on-chain — especially when validating complex calldata, checking for reverts, or estimating gas without spending real funds. Prefer it over on-chain execution for pre-flight safety checks in DeFi, NFT minting, or multisig workflows. Compared to node-native eth_call, this adds policy-gated access, x402 micropayment billing, and a signed receipt for auditability.

## Known failure modes

- Invalid hex calldata format returns a 400 validation error
- Malformed Ethereum address (not 0x + 40 hex chars) causes schema rejection
- Target contract does not exist at the specified address — simulation may return empty result
- Simulation of deeply recursive or out-of-gas calls may time out
- Payment failure via x402 (insufficient USDC balance) blocks the request before simulation runs
- Value field exceeding 78 digits is rejected by schema validation

## How this service works

Tollex lets software agents buy APIs and tools under rules you set: it finds a capability that fits, checks your policy before anything is signed, pays with x402 in USDC on Base or USDG on Robinhood Chain, reconciles uncertain payments and returns a signed receipt.

## Output

Returns the outcome of the simulated EVM transaction, including whether it succeeds or reverts, a revert reason if applicable, gas used, return data, and a signed receipt. No state changes are persisted on-chain.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$"
  },
  "data": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]*$",
   "maxLength": 200000
  },
  "from": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$"
  },
  "value": {
   "type": "string",
   "pattern": "^[0-9]{1,78}$"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "tool": {
   "id": "chain_simulate",
   "version": "1.0.0",
   "provider": "tollex.robinhood-chain"
  },
  "result": {
   "ok": true,
   "returnData": "0x000000000000000000000000000000000000000000000000000000003b9aca00"
  },
  "evidence": [],
  "untrustedOutput": false
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/tollex-chain-simulate-be6e142d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.tollex.org](https://www.zero.xyz/host/api.tollex.org/llms.txt)