Http

Complete HTTP REST API examples for integrating with NextBlock.

HTTP is the simplest way to integrate if you want to submit transactions with JSON requests. If you want the full typed client flow, use the gRPC examples. If you want the lowest-latency submission path, use QUIC Transaction Submission.

API Endpoints

Choose the endpoint closest to your location:

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

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

• London: https://london.nextblock.io

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

• Tokyo: https://tokyo.nextblock.io

• New York: https://ny.nextblock.io

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

• Dublin: https://dublin.nextblock.io

• Vilnius: https://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 https://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 https://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 https://frankfurt.nextblock.io/api/v2/tipfloor \
  -H "Authorization: your-api-key-here"

The language sections in this docs set focus mainly on gRPC and QUIC examples. Use this page as the canonical HTTP request reference.