# Engine

> Engine is an AI agent that trades for you around the clock. Pick a ready-made Spot or Perps strategy (or write your own), fund your account, and the agent follows its rules on your behalf.

Engine is built on the principle that automated trading should be transparent and user-controlled. Traders can write strategies in natural language and connect custom data sources when needed. Each strategy declares whether it trades Spot or Perps markets.

## 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
- [How your agent thinks](https://www.withengine.ai/docs/the-agent): How the trading agent reads markets and applies a strategy
- [Your funds, your control](https://www.withengine.ai/docs/non-custodial-architecture): How Engine keeps portfolio funds and trading authority under user control

### Using Engine
- [Funding your account](https://www.withengine.ai/docs/using/funding-your-vault): How to deposit USDC and fund an Engine account
- [How fees work](https://www.withengine.ai/docs/using/fees): The transaction fees for Spot and Perps trades
- [Plans](https://www.withengine.ai/docs/using/plans): Plans
- [Selecting an agent](https://www.withengine.ai/docs/using/selecting-a-strategy): How to select a Spot or Perps strategy
- [Monitoring your agent](https://www.withengine.ai/docs/using/monitoring-your-agent): Reading activity, positions, holdings, and performance

### Agents
- [What are agents?](https://www.withengine.ai/docs/strategies/what-are-strategies): Strategy structure, lifecycle, and how Engine runs them
- [How agents 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
- [Custom tools and data](https://www.withengine.ai/docs/strategies/custom-tools-and-data): Custom tools and data
- [Supported markets](https://www.withengine.ai/docs/strategies/supported-markets): The live catalog of supported Spot and Perps markets
- [Data your agent can see](https://www.withengine.ai/docs/strategies/available-data): Data your agent can see
- [Ready-made agents](https://www.withengine.ai/docs/strategies/marketplace): How to browse and select ready-made strategies

## Blog
- [Four numbers to know before you open a perp position.](https://www.withengine.ai/blog/four-numbers-before-opening-a-position): Most perp traders open positions on three numbers — entry, size, leverage. There are four worth checking instead: dollar risk, distance to liquidation, daily funding cost, and the worst-case loss at the stop. What each one tells you, and how Engine writes the check into a strategy file you can edit.
- [What a healthy decision log looks like (and three red flags).](https://www.withengine.ai/blog/what-a-healthy-decision-log-looks-like): A trading bot's decision log is the rarest honest thing in the category — and the easiest to fake. The four things a healthy log makes legible, the three red flags that should make you close the tab, and the three questions to ask any product before you let it trade your money.
- [How a trailing stop hurts you, and when it doesn't.](https://www.withengine.ai/blog/how-a-trailing-stop-hurts-you): The trailing stop is sold as a free risk control — let winners run, cut losers short. On perps the math is darker than the sales copy. Three concrete ways a trail bleeds a Hyperliquid perp account, the narrow case where it actually helps, and the shape of the rule we are willing to ship in a strategy file.
- [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
- [Ready-made strategies](https://www.withengine.ai/marketplace): Browse available strategies
- [Terms of Service](https://www.withengine.ai/terms)
- [Privacy Policy](https://www.withengine.ai/privacy)