Substrate API Sidecar

v20.5.0 GitHub

REST service that makes it easy to interact with blockchain nodes built using Substrate's FRAME framework.

Account Management

Query account balances, staking info, and transaction history

Block Explorer

Access detailed block information, extrinsics, and events

Runtime Access

Query runtime metadata, pallets, and storage items

Transaction Tools

Estimate fees, and submit to network

Quick Start

Example Request

curl http://localhost:8080/blocks/head

Getting Started: Use the example cURL commands to test endpoints against your running Substrate API Sidecar instance.

Getting Started

v20.5.0 GitHub

Installation & Setup

1

Install Dependencies

npm

npm install @substrate/api-sidecar

or with Yarn:

yarn

yarn add @substrate/api-sidecar

2

Start the Service

Start Server

substrate-api-sidecar

The service will start on http://localhost:8080 by default.

3

Make Your First Request

Test Request

curl http://localhost:8080/blocks/head

This returns information about the latest block.

Advanced Configuration

Sidecar offers extensive configuration options through environment variables. Here are the most commonly used settings:

Basic Configuration

Environment Variables

# Connect to different networks
export SAS_SUBSTRATE_URL=wss://polkadot-rpc.polkadot.io

# Change server port
export SAS_EXPRESS_PORT=8080

# Set logging level
export SAS_LOG_LEVEL=info

🔗 Node Connection

Configure connections to Substrate nodes, multi-chain setups, and custom type definitions.

🖥️ Server Settings

Control host binding, port, keep-alive timeouts, and request body limits.

📊 Metrics & Monitoring

Enable Prometheus metrics, Loki logging, and performance monitoring.

Complete Configuration Guide: View the comprehensive Advanced Configuration Guide for all available options, examples, and best practices.

Key Features

Account Management

Comprehensive account operations and balance queries

Account balance information
Staking rewards and payouts
Vesting schedules
Transaction history
Multi-signature operations

Block Explorer

Deep blockchain data access and exploration tools

Block information and headers
Extrinsic details and events
Transaction traces
Block range queries
Real-time finality tracking

Runtime Access

Query runtime metadata and pallet information

Runtime metadata
Pallet information
Storage queries
Constant values
Call information

Transaction Tools

Transaction construction and fee estimation

Fee estimation
Dry run operations
Submission queue status
Transaction pool monitoring

Asset Hub Migration Guide

Guide

Asset Hub migration guide content will go here.

useRcBlock Specification

Specification

useRcBlock specification content will go here.

Advanced Configuration Guide

Guide

Comprehensive guide to all Substrate API Sidecar configuration options.