# Blockscout Block Countdown

> Blockscout Block Countdown is a paid API for AI agents from api.blockscout.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-12).

Returns the estimated time remaining until a specific future block number is reached on a given blockchain network

## Facts

- Endpoint: GET https://api.blockscout.com/%7Bchain_id%7D/api/v2/blocks/%7Bblock_number_param%7D/countdown
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/blockscout-block-countdown-c4b20a20
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8rXGAVH0bXyqOhqss3kcC

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 blockscout-block-countdown-c4b20a20
```

Example prompt: How many blocks are left and roughly how many seconds until block 21000000 is reached on Ethereum mainnet using Blockscout?

## When to prefer this

Use this endpoint when you need to estimate when a specific future block will be reached on a supported EVM chain — ideal for scheduling smart contract interactions, monitoring vesting cliffs, governance proposal deadlines, or any time-sensitive on-chain event tied to a block number. Prefer this over manual block-time math for real-time accuracy.

## Known failure modes

- Target block number is in the past — the countdown may return zero or an error
- Invalid chain_id returns a 404 or unsupported chain error
- Block number param is not an integer — schema validation failure
- Target block is too far in the future — estimation accuracy may degrade
- Network unavailable or Blockscout infrastructure outage returns 5xx error

## How this service works

Explore crypto activities with Blockscout's multichain search. Find transactions, addresses, tokens, and dapps across top blockchain networks — your go-to explorer for cross-chain blockchain data

## Output

Returns a JSON object with four string fields: current_block_number (the latest block on the chain), countdown_block_number (the target block queried), remaining_blocks_count (how many blocks until the target), and estimated_time_in_seconds (the time estimate to reach the target block).

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "properties": {
      "chain_id": {
       "type": "string"
      },
      "block_number_param": {
       "type": "integer"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "current_block_number": "string",
  "countdown_block_number": "string",
  "remaining_blocks_count": "string",
  "estimated_time_in_seconds": "string"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/blockscout-block-countdown-c4b20a20/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.blockscout.com](https://www.zero.xyz/host/api.blockscout.com/llms.txt)