Http

Complete HTTP REST API examples for integrating with NextBlock.

API Endpoints

Choose the endpoint closest to your location:

• Frankfurt: http://frankfurt.nextblock.io

• Amsterdam: http://amsterdam.nextblock.io

• London: http://london.nextblock.io

• Singapore: http://singapore.nextblock.io

• Tokyo: http://tokyo.nextblock.io

• New York: http://ny.nextblock.io

• Salt Lake City: http://slc.nextblock.io

• Dublin: http://dublin.nextblock.io

• Vilnius: http://vilnius.nextblock.io

Authentication

All API requests require an API key in the Authorization header:

Authorization: your-api-key-here

Single Transaction Submission

POST /api/v2/submit

POST /api/v2/submit HTTP/1.1
Host: frankfurt.nextblock.io
Content-Type: application/json
Authorization: your-api-key-here

{
  "transaction": {
    "content": "base-64-encoded-transaction"
  },
  "frontRunningProtection": false
}

Response:

{
  "signature": "transaction-signature",
  "uuid": "jito-bundle-uuid"
}

Batched Transaction Submission

POST /api/v2/submit-batch

POST /api/v2/submit-batch HTTP/1.1
Host: frankfurt.nextblock.io
Content-Type: application/json
Authorization: your-api-key-here

{
  "entries": [
    {
      "transaction": {
        "content": "base-64-encoded-transaction-1"
      }
    },
    {
      "transaction": {
        "content": "base-64-encoded-transaction-2"
      }
    }
  ]
}

Response:

{
  "signature": "bundle-signature"
}

Tip Floor API

GET /api/v2/tipfloor

GET /api/v2/tipfloor HTTP/1.1
Host: frankfurt.nextblock.io
Authorization: your-api-key-here

Response:

{
  "time": "2025-05-13T10:41:45Z",
  "landed_tips_25th_percentile": 0.0011,
  "landed_tips_50th_percentile": 0.005000001,
  "landed_tips_75th_percentile": 0.01555,
  "landed_tips_95th_percentile": 0.09339195639999975,
  "landed_tips_99th_percentile": 0.4846427910400001,
  "ema_landed_tips_50th_percentile": 0.005989477267191758
}

cURL Examples

# Submit single transaction
curl -X POST http://frankfurt.nextblock.io/api/v2/submit \
  -H "Content-Type: application/json" \
  -H "Authorization: your-api-key-here" \
  -d '{
    "transaction": {
      "content": "AjF+B...BCQ=="
    },
    "frontRunningProtection": false
  }'

# Submit batched transactions
curl -X POST http://frankfurt.nextblock.io/api/v2/submit-batch \
  -H "Content-Type: application/json" \
  -H "Authorization: your-api-key-here" \
  -d '{
    "entries": [
      {
        "transaction": {
          "content": "ASrTNkPOT...BCQ=="
        }
      },
      {
        "transaction": {
          "content": "AVFRplUyy...BCQ=="
        }
      }
    ]
  }'

# Get tip floor data
curl -X GET http://frankfurt.nextblock.io/api/v2/tipfloor \
  -H "Authorization: your-api-key-here"

For complete language-specific HTTP client implementations with error handling, retry logic, and connection management, see the detailed examples in the other language sections (Go, Rust, Python, JavaScript).