# Base Withdrawal Decoder & Finalizer (post-Beryl)

> Base Withdrawal Decoder & Finalizer (post-Beryl) is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.04/call, status unknown (last checked 2026-09-14).

Decodes a Base withdrawal-initiation transaction to extract the L2ToL1MessagePasser event details and estimates finalization windows under post-Beryl (2026-06-25) rules.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/base-withdrawal
- Price: $0.04/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-withdrawal-decoder-finalizer-post-beryl-2f452410
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4swk_TJRPiesGnLXBsIPn

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 base-withdrawal-decoder-finalizer-post-beryl-2f452410
```

Example prompt: I just initiated a Base withdrawal — can you decode tx 0x4a3f...c2b1 and tell me the withdrawalHash, target, value, and when I'll be able to prove and finalize it on L1 under the new Beryl rules?

## When to prefer this

Use this endpoint when managing cross-chain liquidity on Base and you need to programmatically determine the parameters and timing required to prove and finalize a withdrawal on L1, especially after the Beryl upgrade changed the withdrawal windows. Prefer this over manual RPC calls when you need structured, decoded output with timing estimates ready for automation.

## Known failure modes

- Invalid or non-existent transaction hash returns an error
- Transaction hash is not a withdrawal-initiation tx (wrong event type)
- Base RPC unavailable causing lookup failure
- Tx not yet indexed or too recent
- Payment not processed — 402 payment required error

## How this service works

🆕 Beryl (2026-06-25) cut the single-proof withdrawal window from 7 days to 5, with a dual-proof fast path at ~1 day. Given a Base withdrawal-initiation tx, this decodes the L2ToL1MessagePasser event (the withdrawalHash, target & value needed to prove/finalize on L1) and estimates the finalization windows under the post-Beryl rules. For agents managing cross-chain liquidity.

## Output

Returns the decoded L2ToL1MessagePasser event fields (withdrawalHash, target, value) from the withdrawal-initiation transaction, plus estimated timing windows for the single-proof path (~5 days) and the dual-proof fast path (~1 day) under post-Beryl rules, helping agents know when to trigger prove/finalize calls on L1.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "tx"
     ],
     "properties": {
      "tx": {
       "type": "string",
       "description": "Base withdrawal-initiation txHash"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-withdrawal-decoder-finalizer-post-beryl-2f452410/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)