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Amp provides powerful SQL querying capabilities for blockchain data through two complementary interfaces: Arrow Flight (gRPC) and JSON Lines (HTTP). Both interfaces support the full DataFusion SQL engine, enabling complex queries across blockchain datasets.

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Query Interfaces

Amp exposes two query endpoints, each optimized for different use cases:

Arrow Flight

High-performance gRPC interface for batch and streaming queriesPort: 1602
Protocol: gRPC
Format: Apache Arrow columnar data
Streaming: Yes

JSON Lines

Simple HTTP interface for ad-hoc queries and integrationsPort: 1603
Protocol: HTTP
Format: Newline-delimited JSON
Streaming: No

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When to Use Each Interface

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Use Arrow Flight When:

  • High performance is critical - Columnar format and gRPC provide maximum throughput
  • Streaming data is needed - Real-time updates as new blocks arrive
  • You have Arrow-compatible tools - Python (pyarrow), Rust, or other Arrow ecosystem tools
  • Large result sets - Efficient streaming prevents memory issues

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Use JSON Lines When:

  • Simplicity is preferred - Standard HTTP POST with curl or any HTTP client
  • Batch queries only - One-time queries that don’t need streaming
  • JSON output required - Easy integration with JSON-based systems
  • Quick prototyping - Fastest way to explore data interactively

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SQL Query Support

Both interfaces use Apache DataFusion as the SQL engine, providing:
  • Standard SQL syntax - SELECT, WHERE, JOIN, GROUP BY, ORDER BY, and more
  • Blockchain-specific functions - EVM decoding, hex conversion, unit shifting
  • Namespace/table syntax - Query datasets with namespace/dataset.table
  • User-defined functions (UDFs) - Custom functions for blockchain data processing
See SQL Basics for detailed syntax and examples.

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Default Server Ports

When you start ampd server, both endpoints are available by default: 
ampd server
# Arrow Flight: localhost:1602
# JSON Lines:   localhost:1603
You can configure these ports in .amp/config.toml: 
flight_addr = "0.0.0.0:1602"
jsonl_addr = "0.0.0.0:1603"
Or selectively enable specific endpoints: 
# Start only Arrow Flight endpoint
ampd server --flight-server

# Start only JSON Lines endpoint
ampd server --jsonl-server

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Quick Start Examples

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Arrow Flight (Python)

import pyarrow.flight as flight

client = flight.connect("grpc://localhost:1602")

info = client.get_flight_info(
    flight.FlightDescriptor.for_command(
        b"SELECT * FROM eth_rpc.blocks LIMIT 10"
    )
)

reader = client.do_get(info.endpoints[0].ticket)
table = reader.read_all()
print(table.to_pandas())

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JSON Lines (curl)

curl -X POST http://localhost:1603 \
  --data "SELECT * FROM eth_rpc.blocks LIMIT 10"

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Next Steps

SQL Basics

Learn SQL syntax, namespace/table patterns, and common queries

Arrow Flight

Connect with Python, Rust, or other gRPC clients

JSON Lines

Query via HTTP with curl or any HTTP client

Streaming

Set up real-time streaming queries

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