---
title: "Chain Simulation"
method: POST
path: "/v1/chain-simulation"
tags: ["blockchain"]
---

# Chain Simulation

`POST /v1/chain-simulation`

## Request

- Base URL: `https://agent.pocket.network`
- URL: `https://agent.pocket.network/v1/chain-simulation`
- Auth: none required

Pre-sign EVM transaction simulation: an eth_call with state overrides previewing the revert reason and asset deltas before you sign. POST /v1/chain with the call {to, data, ...} and get the outcome as one JSON object. Deterministic per state instant. Pay per request in USDC; no account, no API key.

## Request body

- object: The call to simulate before signing.
  - `to` string, required: Target contract address, 0x-prefixed.
  - `data` string: Calldata, 0x-prefixed (0x for none).
  - `from` string: Optional sender address.
  - `chain_id` integer: EVM chain id (default 1).

## Response `200`

The upstream response, served after payment settles.

- object: For POST /v1/chain, a JSON object with the simulated outcome: success or revert reason, asset deltas, and the chain_id. The exact shape is the service's own and is not pinned here; errors return a JSON object with an `error` field, and the GET routes return their own small JSON documents.

## Other responses

- `400`: Malformed request.
- `402`: Payment required. The x402 v2 terms are in the PAYMENT-REQUIRED header and, identically, in this body; sign the chosen option and retry with the PAYMENT-SIGNATURE header. The receipt arrives in PAYMENT-RESPONSE.
- `503`: This service is not currently available to serve.

---

[API](https://skmtc.dev/pocket/apis/pocket-agentic-portal.md) · [All operations](https://skmtc.dev/pocket/apis/pocket-agentic-portal/llms.txt) · [OpenAPI document](https://skmtc.dev/pocket/apis/pocket-agentic-portal/revisions/96d2176db014?raw)