Batch Requests

Overview

Lasso RPC supports JSON-RPC batch requests, allowing you to send multiple RPC calls in a single HTTP request. This reduces network overhead and improves throughput for bulk operations.

Batch Request Format

Send an array of JSON-RPC request objects instead of a single object.

Single Request

{"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1}

Batch Request

[
  {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
  {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
]

Basic Example

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x8471c9a"},
  {"jsonrpc":"2.0","id":2,"result":"0x1"}
]

Responses are returned in the same order as the requests, preserving the request array order.

Batch Size Limit

Maximum 50 requests per batch (configurable via max_batch_requests application config). Exceeding the limit returns an error:

{
  "jsonrpc": "2.0",
  "id": null,
  "error": {
    "code": -32600,
    "message": "Invalid Request: batch too large"
  }
}

Advanced Examples

Account Balance and Nonce

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_getBalance","params":["0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb","latest"],"id":1},
    {"jsonrpc":"2.0","method":"eth_getTransactionCount","params":["0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb","latest"],"id":2}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x1bc16d674ec80000"},
  {"jsonrpc":"2.0","id":2,"result":"0x5"}
]

Multiple Contract Calls

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","data":"0x18160ddd"},"latest"],"id":1},
    {"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","data":"0x313ce567"},"latest"],"id":2},
    {"jsonrpc":"2.0","method":"eth_call","params":[{"to":"0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48","data":"0x95d89b41"},"latest"],"id":3}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x000000000000000000000000000000000000000000000000000000174876e800"},
  {"jsonrpc":"2.0","id":2,"result":"0x0000000000000000000000000000000000000000000000000000000000000006"},
  {"jsonrpc":"2.0","id":3,"result":"0x0000000000000000000000000000000000000000000000000000000000000020..."}
]

Mixed Methods

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_gasPrice","params":[],"id":2},
    {"jsonrpc":"2.0","method":"eth_maxPriorityFeePerGas","params":[],"id":3},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":4}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x8471c9a"},
  {"jsonrpc":"2.0","id":2,"result":"0x3b9aca00"},
  {"jsonrpc":"2.0","id":3,"result":"0x59682f00"},
  {"jsonrpc":"2.0","id":4,"result":"0x1"}
]

Historical Log Queries

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_getLogs","params":[{"fromBlock":"0x1000000","toBlock":"0x1000100","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]}],"id":1},
    {"jsonrpc":"2.0","method":"eth_getLogs","params":[{"fromBlock":"0x1000100","toBlock":"0x1000200","topics":["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"]}],"id":2}
  ]'

Batch Requests with Strategies

Batch requests work with all routing strategies.

Fastest Strategy

curl -X POST http://localhost:4000/rpc/fastest/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
  ]'

Provider Override

curl -X POST http://localhost:4000/rpc/provider/alchemy/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
  ]'

Profile-Scoped

curl -X POST http://localhost:4000/rpc/profile/testnet/load-balanced/base \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
  ]'

Error Handling

Batch requests return partial results if some requests fail.

Mixed Success and Error

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_subscribe","params":["newHeads"],"id":2},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":3}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x8471c9a"},
  {
    "jsonrpc":"2.0",
    "id":2,
    "error":{
      "code":-32601,
      "message":"Method not supported over HTTP. Use WebSocket connection for subscriptions.",
      "data":{"websocket_url":"/ws/rpc/ethereum"}
    }
  },
  {"jsonrpc":"2.0","id":3,"result":"0x1"}
]

Invalid Request in Batch

curl -X POST http://localhost:4000/rpc/ethereum \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"invalid":"request"},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":3}
  ]'

Response:

[
  {"jsonrpc":"2.0","id":1,"result":"0x8471c9a"},
  {
    "jsonrpc":"2.0",
    "id":null,
    "error":{"code":-32600,"message":"Invalid Request"}
  },
  {"jsonrpc":"2.0","id":3,"result":"0x1"}
]

Performance Optimization

Lasso optimizes batch requests with zero-copy passthrough when possible.

Passthrough Conditions

Batch responses use raw bytes directly from upstream providers when:

All requests succeed
All responses are Response.Success structs
Observability metadata is not requested in body (include_meta not set to body)

Observability with Batches

curl -X POST 'http://localhost:4000/rpc/ethereum?include_meta=headers' \
  -H 'Content-Type: application/json' \
  -d '[
    {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
    {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2}
  ]' -i

Response headers include:

X-Lasso-Request-ID: Request tracking ID
X-Lasso-Meta: Metadata for first successful request

For batch requests, observability metadata in headers represents the first request with a valid context. Use include_meta=body for per-request metadata (degrades performance).

Request IDs

Each request in a batch must have a unique id field for proper response correlation.

Good Practice

[
  {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
  {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":2},
  {"jsonrpc":"2.0","method":"eth_gasPrice","params":[],"id":3}
]

Bad Practice

[
  {"jsonrpc":"2.0","method":"eth_blockNumber","params":[],"id":1},
  {"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1},
  {"jsonrpc":"2.0","method":"eth_gasPrice","params":[],"id":1}
]

Duplicate IDs make it impossible to correlate responses with requests. Always use unique IDs.

Best Practices

Batch Size

Keep batches under 50 requests (hard limit)
Optimal batch size: 10-20 requests for balance between throughput and latency
Larger batches may trigger provider rate limits

Request Ordering

Group related requests together
Place high-priority requests first
Consider response time variance

Error Recovery

Check each response individually for errors
Implement retry logic for failed requests
Don’t assume all-or-nothing success

Use Cases

Good for batching:

Multiple account balances
Multiple contract read calls
Block metadata queries
Token holder data

Bad for batching:

Subscription requests (eth_subscribe not supported over HTTP)
Write operations (not supported)
Single high-priority request (no latency benefit)

Configuration

Configure batch size limit in your application config:

config :lasso, max_batch_requests: 50

Default: 50

HTTP API

WebSocket API

Management API

Reference

Batch Requests

Overview

Batch Request Format

Single Request

Batch Request

Basic Example

Batch Size Limit

Advanced Examples

Account Balance and Nonce

Multiple Contract Calls

Mixed Methods

Historical Log Queries

Batch Requests with Strategies

Fastest Strategy

Provider Override

Profile-Scoped

Error Handling

Mixed Success and Error

Invalid Request in Batch

Performance Optimization

Passthrough Conditions

Observability with Batches

Request IDs

Good Practice

Bad Practice

Best Practices

Batch Size

Request Ordering

Error Recovery

Use Cases

Configuration

​Overview

​Batch Request Format

​Single Request

​Batch Request

​Basic Example

​Batch Size Limit

​Advanced Examples

​Account Balance and Nonce

​Multiple Contract Calls

​Mixed Methods

​Historical Log Queries

​Batch Requests with Strategies

​Fastest Strategy

​Provider Override

​Profile-Scoped

​Error Handling

​Mixed Success and Error

​Invalid Request in Batch

​Performance Optimization

​Passthrough Conditions

​Observability with Batches

​Request IDs

​Good Practice

​Bad Practice

​Best Practices

​Batch Size

​Request Ordering

​Error Recovery

​Use Cases

​Configuration

Overview

Batch Request Format

Single Request

Batch Request

Basic Example

Batch Size Limit

Advanced Examples

Account Balance and Nonce

Multiple Contract Calls

Mixed Methods

Historical Log Queries

Batch Requests with Strategies

Fastest Strategy

Provider Override

Profile-Scoped

Error Handling

Mixed Success and Error

Invalid Request in Batch

Performance Optimization

Passthrough Conditions

Observability with Batches

Request IDs

Good Practice

Bad Practice

Best Practices

Batch Size

Request Ordering

Error Recovery

Use Cases

Configuration