Stellar Data Tool

A command line tool and REST API for querying the Stellar blockchain using public data lakes and RPC nodes, providing JSON formatted responses to simplify data availability.

Quick Start

cargo install --locked stellar-data
stellar-data --help

Overview

This tool downloads Stellar ledger data from the public S3 bucket at s3://aws-public-blockchain/v1.1/stellar/ledgers/, decompresses the Zstandard compressed XDR data, and converts it to JSON format. If data isn't available (Most recent blocks) it falls back to querying an RPC node.

Available currently for Stellar mainnet only. Testnet coming soon (hopefully)

Published to: https://crates.io/crates/stellar-data

Features

• Dual Mode Operation: Use as CLI tool or REST API server
• Downloads ledger data directly from AWS S3 public data lake
• Automatically calculates correct S3 paths using partition and batch logic
• Decompresses Zstandard (.zst) compressed files
• Parses XDR (External Data Representation) format
• Converts to human-readable JSON
• Supports filtering for specific data types (transactions, all data, address-based)
• Query single ledgers or ranges of ledgers
• Query recent ledgers using negative values (e.g., -999 for last 999 blocks)
• Filter transactions by Stellar address
• REST API: HTTP endpoints for web application integration
• Smart Contract Queries: Filter by contract address or function name
• Token Balances: Query current balances with built-in token shortcuts
• Automatic RPC Fallback: Seamless fallback to RPC for most recent ledgers

Installation

Build from source

cargo build --release

The binary will be available at ./target/release/stellar-data

Usage

The tool can be used in two modes:

1. CLI Mode: Direct command-line queries with output to stdout
2. REST API Mode: HTTP server exposing API endpoints

CLI Mode

Basic syntax:

stellar-data --ledger <LEDGER_NUMBER | RANGE> --query <QUERY_TYPE> [--address <ADDRESS>]

Options

• --ledger, -l: The ledger/block number or range to query (required)
  • Single ledger: --ledger 63864
  • Ledger range: --ledger 63864-63900
  • Recent ledgers (negative): --ledger -999 (queries last 999 blocks from current)
• --query, -q: Query type - all, transactions, address, or ttl (default: all)
• --address, -a: Stellar address to filter by (required when --query address or --query ttl)

Examples

Get all data for a specific ledger

./target/release/stellar-data --ledger 63864 --query all

Output includes the full ledger close metadata:

• Ledger header information
• Transaction set
• Transaction processing details
• SCP (Stellar Consensus Protocol) info
• Upgrade processing

Get only transactions from a ledger

./target/release/stellar-data --ledger 50000000 --query transactions

Output format:

{
  "start_sequence": 50000000,
  "end_sequence": 50000000,
  "count": 721,
  "transactions": [
    {
      "tx": {
        "signatures": [...],
        "tx": {
          "source_account": "...",
          "fee": 5000,
          "seq_num": "...",
          "operations": [...],
          "memo": "none",
          "cond": {...}
        }
      }
    }
  ]
}

Get early Stellar ledger (may have no transactions)

./target/release/stellar-data --ledger 63864 --query transactions

Query a range of ledgers for all transactions

./target/release/stellar-data --ledger 50000000-50000010 --query transactions

Output format:

{
  "start_sequence": 50000000,
  "end_sequence": 50000010,
  "ledgers_processed": 11,
  "address": null,
  "count": 7945,
  "transactions": [...]
}

Query the most recent N ledgers

Get transactions from the last 10 blocks:

./target/release/stellar-data --ledger -10 --query transactions

The tool will automatically fetch the current latest ledger from Horizon and work backwards.

Output format:

{
  "start_sequence": 59423252,
  "end_sequence": 59423261,
  "ledgers_processed": 10,
  "address": null,
  "count": 5621,
  "transactions": [...]
}

Search for transactions involving a specific address

Single ledger:

./target/release/stellar-data --ledger 50000000 --query address --address GCWGA2XKBSKVAAPN3UKG2V4TA2O4UDOQEVNNND5GPRLBC63DDEUM3G2I

Ledger range:

./target/release/stellar-data --ledger 63864-638900 --query address --address GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB

Recent blocks with address filter:

./target/release/stellar-data --ledger -999 --query address --address GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB

Get TTL for a contract (code + instance)

./target/release/stellar-data --query ttl --address C123...ABC

The address filter searches for:

• Source accounts in transactions
• Source accounts in operations
• Destination accounts in payments
• Asset issuers in trust lines
• Trustors in trust operations
• And other address-related fields

Output format:

{
  "start_sequence": 63864,
  "end_sequence": 638900,
  "ledgers_processed": 575037,
  "address": "GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB",
  "count": 42,
  "transactions": [...]
}

REST API Mode

Start the API server to enable HTTP access to Stellar blockchain data:

./target/release/stellar-data --server --port 3000

Or use the default port (80):

./target/release/stellar-data --server

Once started, the server will display:

Stellar Data API Server
======================
Listening on http://0.0.0.0:3000

Available endpoints:
  GET /help
  GET /transactions?ledger=<LEDGER>&address=<ADDRESS>
  GET /all?ledger=<LEDGER>
  GET /contract?ledger=<LEDGER>&address=<CONTRACT>
  GET /function?ledger=<LEDGER>&name=<FUNCTION>
  GET /balance?address=<ADDRESS>&token=<TOKEN>

REST API Endpoints

All endpoints return JSON responses (except /help which returns HTML documentation).

GET /help

Returns an interactive HTML documentation page with detailed information about all endpoints.

curl http://localhost:3000/help

Or visit http://localhost:3000/help in your browser for a formatted documentation page.

GET /transactions

Get transactions from specified ledger(s), optionally filtered by address.

Parameters:

• ledger (required): Ledger sequence number, range, or negative value
• address (optional): Stellar address to filter transactions

Examples:

# Single ledger
curl "http://localhost:3000/transactions?ledger=50000000"

# Ledger range
curl "http://localhost:3000/transactions?ledger=50000000-50000005"

# Recent ledgers
curl "http://localhost:3000/transactions?ledger=-10"

# Filter by address
curl "http://localhost:3000/transactions?ledger=50000000&address=GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB"

Response:

{
  "start_sequence": 50000000,
  "end_sequence": 50000005,
  "ledgers_processed": 6,
  "address": null,
  "transactions": [...],
  "count": 4523
}

GET /all

Get complete ledger metadata including all transaction processing details.

Parameters:

• ledger (required): Ledger sequence number, range, or negative value

Examples:

# Single ledger
curl "http://localhost:3000/all?ledger=50000000"

# Ledger range
curl "http://localhost:3000/all?ledger=50000000-50000002"

# Recent ledgers
curl "http://localhost:3000/all?ledger=-5"

Response:

{
  "start_sequence": 50000000,
  "end_sequence": 50000000,
  "ledgers_processed": 1,
  "ledgers": [...],
  "count": 1
}

GET /contract

Get transactions involving a specific smart contract.

Parameters:

• ledger (required): Ledger sequence number, range, or negative value
• address (required): Contract address (starts with 'C')

Examples:

# Search contract invocations in ledger range
curl "http://localhost:3000/contract?ledger=50000000-50000010&address=CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC"

# Search recent ledgers
curl "http://localhost:3000/contract?ledger=-100&address=CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC"

Response:

{
  "start_sequence": 50000000,
  "end_sequence": 50000010,
  "ledgers_processed": 11,
  "contract": "CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC",
  "transactions": [...],
  "count": 15
}

GET /function

Get transactions calling a specific contract function by name.

Parameters:

• ledger (required): Ledger sequence number, range, or negative value
• name (required): Function name (e.g., 'transfer', 'approve', 'mint')

Examples:

# Search for transfer function calls
curl "http://localhost:3000/function?ledger=50000000-50000100&name=transfer"

# Search recent ledgers for approve calls
curl "http://localhost:3000/function?ledger=-1000&name=approve"

Response:

{
  "start_sequence": 50000000,
  "end_sequence": 50000100,
  "ledgers_processed": 101,
  "function": "transfer",
  "transactions": [...],
  "count": 234
}

GET /balance

Get current token balance for a Stellar address using RPC.

Parameters:

• address (required): Stellar account address
• token (required): Token contract address or shortcut

Token Shortcuts:

• xlm - Native Stellar Lumens
• usdc - USD Coin
• usdt - Tether USD
• aqua - Aquarius token
• btc - Bitcoin (wrapped)

Examples:

# Get XLM balance
curl "http://localhost:3000/balance?address=GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB&token=xlm"

# Get USDC balance
curl "http://localhost:3000/balance?address=GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB&token=usdc"

# Get balance for specific token contract
curl "http://localhost:3000/balance?address=GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB&token=CDLZFC3SYJYDZT7K67VZ75HPJVIEUVNIXF47ZG2FB2RMQQVU2HHGCYSC"

Response:

{
  "address": "GALPCCZN4YXA3YMJHKL6CVIECKPLJJCTVMSNYWBTKJW4K5HQLYLDMZTB",
  "token": "CAS3J7GYLGXMF6TDJBBYYSE3HQ6BBSMLNUQ34T6TZMYMW2EVH34XOWMA",
  "balance": "1121995790",
  "raw_balance": 1121995790
}

REST API Features

• CORS Enabled: The API has permissive CORS enabled for easy integration with web applications
• Automatic Fallback: Recent ledgers automatically fall back to RPC when not available in S3
• Error Resilience: Individual ledger failures in ranges don't stop processing
• Interactive Documentation: Visit /help endpoint in a browser for full interactive documentation

REST API vs CLI Mode

Feature	CLI Mode	REST API Mode
Use Case	One-time queries, scripts, automation	Web applications, continuous access, integration
Output	stdout (console)	HTTP JSON responses
Concurrency	Single query per invocation	Multiple concurrent requests
Setup	Run directly	Start server once
Documentation	--help flag	Interactive /help endpoint

How It Works

URL Generation

The tool calculates the S3 URL based on the ledger sequence number using the following format:

https://aws-public-blockchain.s3.us-east-2.amazonaws.com/v1.1/stellar/ledgers/pubnet/{PARTITION}/{BATCH}.xdr.zst

Where:

• Partition: Groups of 64,000 ledgers formatted as FFFFFFFF--{start}-{end}
• Batch: Individual ledgers (batch size = 1) formatted as FFFFFFFF--{ledger}.xdr.zst

Example for ledger 63864:

FFFFFFFF--0-63999/FFFF0687--63864.xdr.zst

The hexadecimal values are calculated as 0xFFFFFFFF - ledger_sequence.

Data Processing Pipeline

1. Fetch Latest Ledger (if using negative values): Queries Stellar Horizon API for current ledger
2. Download: Fetches compressed XDR data from S3
3. Decompress: Uses Zstandard decompression
4. Parse: Decodes XDR into LedgerCloseMetaBatch structure
5. Convert: Serializes to JSON using the stellar-xdr crate's serde support

Configuration

The tool uses these default values from the S3 data lake configuration:

• Network: Public Global Stellar Network (mainnet)
• Compression: Zstandard
• Ledgers per batch: 1
• Batches per partition: 64,000
• Base URL: https://aws-public-blockchain.s3.us-east-2.amazonaws.com

Data Structure

The XDR files contain LedgerCloseMetaBatch structures with:

struct LedgerCloseMetaBatch {
    start_sequence: u32,
    end_sequence: u32,
    ledger_close_metas: Vec<LedgerCloseMeta>,
}

Each LedgerCloseMeta can be V0, V1, or V2 format, containing:

• Ledger header with sequence number, timestamps, hashes
• Transaction set with all transactions in the ledger
• Transaction processing results
• Upgrade processing information
• SCP consensus information

Publishing Notes

There's a bug in WSL that prevents metadata, use Windows console

cargo test
cargo login
cargo clean
cargo package
cargo publish --dry-run
cargo publish

AI Prompts

The major prompts that I used with Claude Code and Codex can be found in the prompts/ directory which has been published with the code to provide some insight in to the assisted development process I use.

Nb. the compounding bug was a stickler

References

• Stellar Public Data Documentation
• stellar-xdr Rust Crate
• AWS Public Blockchain Data

License

MIT

Contributions

Feel free to improve and put in a pull request ♥️