ON1Builder

pip install -e .

Async, multi-chain MEV/arbitrage engine with safety rails, flashloan support, and live telemetry. Highly customizable via config.

Overview

ON1Builder is a modular MEV searcher framework designed for building and deploying arbitrage, front-running, and back-running strategies across multiple EVM-compatible blockchains. It emphasizes safety, configurability, and observability, making it suitable for both development and production environments.

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Key Features

• Multi-Chain Support: Easily connect to any EVM-compatible chain with configurable RPC and WebSocket endpoints (prefers Nethermind, Geth nodes).
• MEV Strategies: Built-in support for common MEV strategies including arbitrage, front-running, back-running, and flashloan-based trades.
• Safety Mechanisms: Configurable slippage caps, gas price ceilings, and balance tiers to minimize risk.
• Flashloan Integration: Seamless integration with popular flashloan providers for capital-efficient trading.
• Simulation Backends: Supports multiple simulation backends (eth_call, Anvil, Tenderly) for pre-execution validation.
• Telemetry & Monitoring: Heartbeats, performance summaries, structured logging, and notification channels (Slack, Telegram, Discord, Email) for real-time monitoring.
• Extensible Architecture: Modular design allows for easy addition of new strategies, chains, and features.

Quick Snapshot

Track	Summary
Core Focus	MEV searcher: arbitrage, back/front-run, flashloans
Chains	Ethereum ready (public RPC OK); multi-chain capable
Safety	Slippage caps, gas ceilings, balance tiers, emergency stop
Telemetry	Heartbeats, perf summaries, structured logs, notifications

Feature Highlights

Quick Start

1. Clone & env

git clone https://github.com/John0n1/ON1Builder.git
cd ON1Builder

• Windows

python -m venv .venv
. .venv/Scripts/activate
pip install -r requirements.txt
pip install -e .

• Linux/MacOS

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
pip install -e .

2. Configure (minimum)

copy .env.example .env
# edit:
#   WALLET_KEY, WALLET_ADDRESS
#   RPC_URL_1="https://ethereum-rpc.publicnode.com"
#   WEBSOCKET_URL_1="wss://ethereum-rpc.publicnode.com"   # public WS is auto-skipped for txpool
#   ETHERSCAN_API_KEY=...

3. Run

python -m on1builder status check
python -m on1builder run start

With public RPC/WS, txpool scanning is disabled on purpose (unreliable pending tx support). Provide a private WS endpoint if you want pending tx monitoring.

Architecture

Module Dependency Graph

cli/               → config/, core/
core/              → config/, engines/, integrations/, monitoring/, persistence/, utils/
engines/           → config/, integrations/, utils/
integrations/      → config/, utils/
monitoring/        → config/, integrations/, utils/
persistence/       → config/, utils/
utils/             → (standalone, no internal deps except config.loaders)

Key Design Patterns

Pattern	Where	Purpose
Singleton	ExternalAPIManager, NonceManager, DatabaseInterface, NotificationService	Shared state, connection pooling
Circuit Breaker	error_recovery.py	Protect against cascading failures
Async Context Manager	DatabaseInterface, NotificationService	Guaranteed resource cleanup
Strategy	StrategyExecutor	Pluggable MEV strategies
Observer	TxPoolScanner → StrategyExecutor	Decouple mempool monitoring from execution

Configuration Cheat Sheet

Setting	Description
WALLET_KEY, WALLET_ADDRESS	Required for signing/monitoring
RPC_URL_1	HTTP RPC endpoint (public OK)
WEBSOCKET_URL_1	WS endpoint; use private if you want txpool scanning
ETHERSCAN_API_KEY	Optional but recommended for ABI/tx metadata
MIN_PROFIT_ETH	Profit floor per trade (ETH)
MAX_GAS_PRICE_GWEI	Hard gas ceiling
SUBMISSION_MODE	public, private, or bundle (relay submission)
PRIVATE_RPC_URL	Private RPC endpoint (Flashbots Protect, etc.)
BUNDLE_RELAY_URL	Bundle relay endpoint (MEV-Boost/Flashbots)
SIMULATION_BACKEND	eth_call, anvil, or tenderly
SIMULATION_CONCURRENCY	Max concurrent simulations
NOTIFICATION_CHANNELS	slack,telegram,discord,email (blank = off)
ORACLE_FEEDS	JSON map of chain_id → symbol → Chainlink feed address
ORACLE_STALE_SECONDS	Max age (seconds) before oracle price is treated as stale
MARKET_PRICE_PERSIST_INTERVAL	Persist price snapshots to DB every N seconds (0 disables)
STARTUP_TEST_TRANSACTION	Run a diagnostic self-tx on startup (requires ALLOW_INSUFFICIENT_FUNDS_TESTS)
ALLOW_INSUFFICIENT_FUNDS_TESTS	Bypass local balance checks for test sends (debug only)

Full list lives in .env.example.

PublicNode endpoints can be used for EVM chains listed in .env.example. Non-EVM endpoints (Sui, Aptos, Osmosis, Avalanche P/X, Polygon Heimdall) are not supported by ON1Builder.

Running & Monitoring

# Validate config
python -m on1builder status check

# Start bot
python -m on1builder run start

# View logs
tail -f logs/on1builder.log          # *nix
Get-Content logs\\on1builder.log -Wait  # Windows

Heartbeats report balance tier, pending tx count (0 if txpool scanner is disabled), and memory usage.

Testing

# Run all tests (fast, no external deps)
python -m pytest tests/ -q

# Run with verbose output
python -m pytest tests/ -v --tb=short

# Run with coverage report
python -m pytest tests/ --cov=on1builder --cov-report=html

# Run a specific test file
python -m pytest tests/test_edge_cases.py -v

# Run live API tests (requires network access)
RUN_LIVE_API_TESTS=1 python -m pytest tests/test_external_api_integration.py

Test Categories

Category	Files	Focus
Smoke	test_smoke.py	Package imports, version consistency, resource files
Core Logic	test_balance_manager.py, test_nonce_manager_logic.py, test_transaction_manager_logic.py	Balance tiers, nonce management, TX building
Engines	test_safety_and_gas_guardrails.py, test_logic_behaviors.py	Safety guards, strategy execution
Monitoring	test_txpool_end_to_end.py, test_market_data_feed_logic.py, test_websocket_*.py	Mempool scanning, market data, WS resilience
API	test_external_api_logic.py, test_external_api_integration.py	Price feeds, oracle integration
Config	test_config_manager.py, test_validation.py, test_cli_commands.py	Settings loading, validation, CLI
Utils	test_utils.py, test_error_handling.py, test_path_helpers.py, test_logging_config.py	Utilities, error handling, DI container
Edge Cases	test_edge_cases.py	Boundary values, error paths, constants sanity

Development

# Lint and format
black --target-version py312 src tests
python -m compileall -q src tests

# Run full test suite
python -m pytest tests/ -q

Pre-commit hooks are configured in .pre-commit-config.yaml.

Troubleshooting

Problem	Cause	Solution
parsimonious version conflict	eth-abi requires <0.11.0	Use parsimonious>=0.10.0,<0.11.0 (already pinned)
txpool scanning silent	Public WS endpoint	Use a private node (Alchemy, Infura, self-hosted)
ConfigurationError on start	Missing .env values	Run python -m on1builder status check to diagnose
Gas estimation fails	Network congestion / bad RPC	Falls back to default_gas_limit; check RPC health
Notifications not sending	Channels not configured	Set NOTIFICATION_CHANNELS in .env
Tests fail with singleton state	Stale singleton between tests	Each test file resets singletons via fixtures

Optional Utilities

ON1Builder ships a few utilities that are not required for core execution but can be integrated in advanced deployments:

• src/on1builder/utils/error_recovery.py: Retry/circuit-breaker helpers and a recovery manager. The TransactionManager now reports failures to this manager for tracking and optional recovery strategies, but most strategies are placeholders by default.
• src/on1builder/utils/container.py: A lightweight DI container for advanced lifecycle management. The core runtime does not use it yet; opt in if you want centralized wiring.
• src/on1builder/utils/memory_optimizer.py: Memory monitoring and GC management for long-running deployments. Tracks process memory and triggers cleanup when thresholds are exceeded.

Flashloan setup

You need to deploy your own flashloan provider contract or use an existing one. Make sure to configure the flashloan provider address in your strategy settings.

To learn about deploying a flashloan contract, refer to the documentation of the flashloan provider you intend to use (e.g., Aave, dYdX) we recommend Aave

Here's a basic outline of the steps involved:

1. Choose a Flashloan Provider: Decide which flashloan provider you want to use (e.g., Aave, dYdX).
2. We recommend using Remix IDE for deploying smart contracts. Open Remix IDE in your web browser.
3. Create a New File: In Remix, create a new Solidity file (e.g., FlashloanProvider.sol) and write or paste the flashloan contract code.
4. Compile the Contract: Use the Solidity compiler in Remix to compile your flashloan contract.
5. Deploy the Contract:
   • Select the appropriate environment (e.g., Injected Web3 for MetaMask).
   • Choose the contract you want to deploy.
   • Click the "Deploy" button and confirm the transaction in your wallet.
6. Note the Contract Address: After deployment, copy the contract address. You'll need to configure this address in .env

API Keys

The bot is able to function without API keys, but some features are limited. It's recommended to set up the following free API keys for best experience:

• Etherscan API Key: For fetching contract ABIs and transaction metadata. Sign up at Etherscan.
• Tenderly Account: For advanced simulation backend. Sign up at Tenderly.
• CoinGecko API Key: Optional, for additional price data. Sign up at CoinGecko.

Safety Notes

• Public WS endpoints are auto-skipped for txpool scanning to avoid noisy failures.
• Price lookups are limited to a small, well-known token set; repeated failures are silenced after blacklisting.
• Emergency balance tiers keep the bot idle when funds are low.
• Gas estimation includes a 20% buffer with a hard cap at 30M (Ethereum block gas limit).

License

MIT - see LICENSE.

Disclaimer

Use at your own risk. No warranty. MEV strategies can be volatile and may incur losses. Keep keys safe; never use production keys on public demos.