Design Trading Rules Without Writing Code

From idea to rules

Most trading ideas start as a sentence: "sell a straddle at 9:20 on expiry day and exit at a 25% loss on either leg." A builder needs every term defined.

Each answer is a decision that changes the results. Writing the rules out in full before opening the builder is the single most useful step.

The six parts of every strategy

A complete strategy in any builder has six parts. If one is missing, the builder fills it with a default that may not be what you want.

1. Instrument and contract selection

The underlying (Nifty, Bank Nifty, a stock), the product (futures, options, equity), the expiry rule (current weekly, next weekly, monthly) and, for options, the strike selection: ATM, a distance in points or strikes from ATM, a premium nearest to a value, or a delta. Strike rules by premium or delta adapt to volatility; rules by points do not.

2. Entry conditions

A time, an indicator condition, a price level, or a combination. Conditions should be evaluated on closed candles, with a stated timeframe: "15-minute close above the 20 EMA" is precise; "price above the 20 EMA" is not. Add a time window in which entries are allowed, and a limit on the number of entries per day.

3. Position size

Fixed lots, or lots calculated from a rupee risk per trade and the stop distance. Builders that only support fixed lots need the size recalculated when the account or volatility changes. Our position size calculator gives the number.

4. Exit conditions

A stop loss, a target, a trailing rule, a time exit, or a condition such as an indicator crossing back. Specify what each is measured against: the underlying's price, the option's premium or the position's combined MTM. Specify what happens to other legs when one exits. Always include a time exit, so that no position is left to the broker's square-off.

5. Risk limits

A maximum loss per day for the strategy, a maximum number of trades, and an account-level MTM stop loss that overrides everything. These are the rules that keep a bad day from becoming a bad month.

6. Execution settings

Order type (limit with a buffer rather than market), the sequence for multi-leg entries (buy the hedge legs first), re-entry rules after a stop, and what to do if a leg is rejected.

Design principles

• One idea per strategy. A strategy that sells straddles on expiry day and also trades breakouts on other days is two strategies; build them separately so that each can be tested and judged.
• Few parameters. Every adjustable number is a chance to overfit. Prefer standard indicator settings and round numbers until a test shows otherwise.
• Rules that do not depend on hindsight. Entries on closed candles; levels known before the candle that tests them. See look-ahead bias.
• Symmetric treatment. If a stop is 25% of premium, decide the target the same way. Mixed units hide the real risk-reward.
• An exit for every entry. Including a time exit and a what-if-rejected rule.
• Defaults checked. Read every default the builder applies: product type, order validity, square-off time, slippage assumption.

Testing the design

1. Backtest over at least three years with costs and slippage, and read the trade list, not just the summary. Check that the first ten trades did what the rules say. See common backtesting mistakes.
2. Vary one parameter at a time and confirm that neighbouring values give similar results.
3. Paper trade for two to four weeks on live prices, and compare each signal and fill with what the backtest would have shown. See paper vs live trading.
4. Go live small with an MTM stop loss, then scale.

Worked example: an expiry-day short straddle

Written this way, the strategy can be entered in a builder in a few minutes, and the backtest will test the same rules that will trade live. Our short straddle strategy and expiry day strategy guides cover the trading logic.

Where no-code designs fail

• Missing rules. The builder's default square-off time, not yours, closes the position.
• Ambiguous stops. "25% stop" set on the combined premium when the trader meant per leg, or the reverse.
• Unmanaged legs. One leg stops out and the other runs naked with no revised stop.
• Fixed sizes. The same five lots in a quiet month and a volatile one.
• No daily limit. A strategy re-enters after every stop and loses five times in a trending day.
• Tuned parameters. Settings chosen because they fit last quarter.

If an idea cannot be expressed in the builder, consider whether it is precise enough yet. Ideas that are precise and still cannot be built are the case for code; see no-code vs coded strategies.

Building in QuantPower

QuantPower's strategy builder covers each of the six parts: instrument and strike selection rules, indicator and time conditions, per-leg and combined exits, trailing stops, daily limits and limit-order execution with a buffer. Every strategy can be backtested in the backtesting engine and run in paper trading before going live, and the trading automation checklist lists what to confirm before the first live order.

Frequently asked questions