# Anchor Hash to Base + Solana Mainnet

> Anchor Hash to Base + Solana Mainnet is a paid API for AI agents from api.anchor-x402.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Anchors a 32-byte hash to both Base and Solana mainnet blockchains, creating a verifiable dual-chain timestamp proof for $0.005 USDC.

## Facts

- Endpoint: POST https://api.anchor-x402.com/v1/anchor
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-anchor-x402-com-dbf2ec1f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eK7Gz7YQiUoUSDbg-s4Dw

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 api-anchor-x402-com-dbf2ec1f -d '<json body>'
```

Example prompt: Anchor this 32-byte hash to the blockchain — a3f1c9d2b8e047a6f5c2d9b4e8a1f3c7d6b2e5a9f1c4d7b0e3a6f9c2d5b8e1a4 — so I have a dual-chain proof of existence on both Base and Solana mainnet.

## When to prefer this

Use this endpoint when you need a cheap ($0.005 USDC), fast, dual-chain notarization of any 32-byte hash on both Base and Solana mainnet simultaneously. Ideal for proving document existence, content integrity checks, audit trails, and any scenario requiring immutable on-chain timestamps across two chains.

## Known failure modes

- Invalid hash format — hash must be exactly 32 bytes (64 hex characters)
- Payment failure — insufficient USDC balance or x402 payment not accepted
- Blockchain congestion causing delayed confirmation
- Hash already anchored — may return existing anchor or create duplicate
- Network error on one chain — partial anchor with only one chain confirmed

## How this service works

Anchor a 32-byte hash to Base + Solana mainnet — $0.005 USDC

## Output

Returns transaction IDs or receipts confirming the hash was anchored on both Base mainnet and Solana mainnet, providing a verifiable dual-chain timestamp proof of existence for the submitted 32-byte hash.

## Example request

```json
{
 "input": {
  "body": {
   "hash": "a3f1c9d2b8e047a6f5c2d9b4e8a1f3c7d6b2e5a9f1c4d7b0e3a6f9c2d5b8e1a4",
   "note": "QA test anchor for dual-chain timestamp proof"
  },
  "type": "http",
  "method": "POST",
  "bodyType": "json"
 }
}
```

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "properties": {
      "data": {
       "description": "Arbitrary JSON to be canonicalized + SHA-256'd by the server. Mutually exclusive with `hash`."
      },
      "hash": {
       "type": "string",
       "description": "32-byte hex hash (64 chars, no 0x prefix). Mutually exclusive with `data`."
      },
      "note": {
       "type": "string",
       "maxLength": 200,
       "description": "Optional 200-char note returned in the response (not on-chain)."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "base": {
   "tx": "0x7fb4d107d8c1b65b33851434c6fd178b682a143904a2bfa89ff2c1fa70974e96",
   "explorer_url": "https://basescan.org/tx/0x7fb4d107d8c1b65b33851434c6fd178b682a143904a2bfa89ff2c1fa70974e96"
  },
  "solana": {
   "tx": "u8rqU4oSQkkHQw93nCCtQym5crh4UjuoNvYhspLcUTEny59asrNNffpmxpgzRuZ4MXQnN5UEoCKQuDS16ZMPKW2",
   "explorer_url": "https://solscan.io/tx/u8rqU4oSQkkHQw93nCCtQym5crh4UjuoNvYhspLcUTEny59asrNNffpmxpgzRuZ4MXQnN5UEoCKQuDS16ZMPKW2"
  },
  "anchored_at": 1746820000,
  "merkle_root": "ab0898397c86fbf97c99c6f8b29e55ab697315705777ee1d106e2dcb9bd686b3"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-anchor-x402-com-dbf2ec1f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.anchor-x402.com](https://www.zero.xyz/host/api.anchor-x402.com/llms.txt)