# Engine

> Engine is an AI agent that trades for you, around the clock, built on Hyperliquid. You pick a published strategy (or write your own), fund a vault, and the agent trades it on your behalf 24/7. Engine never has withdraw authority on your funds.

Engine is built on the principle that automated trading should be transparent and user-controlled. Trades have the ability to custom write their own strategies and publish them to the marketplace. Strategies, similar to agent skills, allow traders to write natural language rules for their agent to follow when trading. They can also plug in custom endpoints to bring their own data into the agent's decision-making process. Engine never has withdraw authority on your funds.

## Documentation

### Welcome
- [Start here](https://www.withengine.ai/docs/welcome): What Engine is and how to get going in 5 minutes

### What is Engine?
- [What is Engine?](https://www.withengine.ai/docs/what-is-engine): Product overview and core concepts
- [The agent](https://www.withengine.ai/docs/the-agent): How the trading agent is authorized, what it can and can't do
- [Your funds, your control](https://www.withengine.ai/docs/non-custodial-architecture): Custody model: primary wallet vs agent wallet, what Engine can and can't access

### Using Engine
- [Funding your vault](https://www.withengine.ai/docs/using/funding-your-vault): How to deposit USDC and activate trading
- [How fees work](https://www.withengine.ai/docs/using/fees): Tiered transaction fees, fee tiers, and what Engine fees support
- [Selecting a strategy](https://www.withengine.ai/docs/using/selecting-a-strategy): How to read the marketplace and pick a strategy
- [Monitoring your agent](https://www.withengine.ai/docs/using/monitoring-your-agent): Reading the dashboard, pause/resume, withdraw

### Strategies
- [What are strategies?](https://www.withengine.ai/docs/strategies/what-are-strategies): Strategy structure, lifecycle, and how Engine runs them
- [How strategies work](https://www.withengine.ai/docs/strategies/how-strategies-work): The strategy model: identity vs. playbook, and what Engine enforces
- [Building your own](https://www.withengine.ai/docs/strategies/building-your-own): Author a strategy from scratch
- [Supported markets](https://www.withengine.ai/docs/strategies/supported-markets): The full catalog of tradable markets — crypto, US equities, commodities
- [The marketplace](https://www.withengine.ai/docs/strategies/marketplace): How published strategies are discovered and curated

## Blog
- [What a basis trade looks like on Hyperliquid.](https://www.withengine.ai/blog/basis-trades-on-hyperliquid): A basis trade is the cleanest way to harvest funding on Hyperliquid — and the cleanest way to lose money if you misread the venue. How the trade actually works, why the venue's quirks change the math, and the three failure modes that take a working basis trade and turn it into a slow drain.
- [What a regime gate actually does for your P&L.](https://www.withengine.ai/blog/what-a-regime-gate-does-for-pnl): Most strategies have an entry block and a sizing block and stop there. The regime gate is the third — a small condition that decides when not to run, and on a Hyperliquid trading strategy it usually saves more risk than the signal block earns. What it actually does, with numbers, and how to write one you can edit.
- [Sizing positions by Kelly versus fixed-fractional, in practice.](https://www.withengine.ai/blog/kelly-vs-fixed-fractional-sizing): Kelly and fixed-fractional are the two sizing rules every perp trader has heard of and almost no one runs verbatim. What each one actually says, why the real answer is a compromise, and how to express it in a strategy file you can edit.
- [Open interest as a signal: when it works, when it lies.](https://www.withengine.ai/blog/open-interest-as-a-signal): Open interest is one of the most-quoted numbers in perp trading and one of the most misread. A field guide to what OI on Hyperliquid actually measures, the three ways it lies, and the only way we trust it inside a strategy file.
- [Reading the liquidation map: what it tells you and what it doesn't.](https://www.withengine.ai/blog/reading-the-liquidation-map): Liquidation maps on Hyperliquid look like X-ray vision into where leveraged perp traders will get blown out next. They are useful — and they hide more than most readers notice. A field guide to reading them without overreading them.
- [Why every backtest you've ever seen is too optimistic.](https://www.withengine.ai/blog/why-every-backtest-is-too-optimistic): Three structural reasons a crypto strategy backtest beats the live version — the universe the backtest got to pick, the costs it quietly skipped, and the fills it never had to fight for. What to look for, and what to demand before you trust a curve.
- [Engine vs. every other trading bot.](https://www.withengine.ai/blog/engine-vs-every-other-bot): Three structural differences between Engine and every other trading bot in the category — where your funds sit, what you can see, and whose strategy is actually running.
- [Funding rates on Hyperliquid: a field guide for the merely curious.](https://www.withengine.ai/blog/funding-rates-on-hyperliquid): How funding works on Hyperliquid: the only perp fee that pays one side at the other's expense, and how to read the regimes that matter.
- [Writing your first strategy, line by line.](https://www.withengine.ai/blog/writing-your-first-strategy): A walkthrough of Funding Harvester, the simplest profitable strategy we publish. The four blocks, what each does, and the two failure modes to design out.
- [The case for transparent agent trading.](https://www.withengine.ai/blog/the-case-for-transparent-agent-trading): Most automated trading is sold as a black box. Why we built Engine the other way around, and what transparency means in practice.

## Optional
- [Strategy marketplace](https://www.withengine.ai/marketplace): Browse all published strategies (dynamic — individual strategy pages not enumerated here)
- [Terms of Service](https://www.withengine.ai/terms)
- [Privacy Policy](https://www.withengine.ai/privacy)