Source, condition, filter: what a rule is made of, three that work, and the usual mistakes.

The table shows you what is happening now. An alert exists so you do not have to live in the table. The difference between «I checked» and «it reached me» is the difference between a hobby and a working tool.

What a rule is made of

A rule is a chain of three links:

Source — where the events come from. A specific exchange, a group of exchanges or a market type.

Condition — what exactly has to happen. A spread, a funding rate, a jump in open interest, a new coin listing, a liquidation, withdrawals closing.

Filter — the circumstances under which you care: a threshold in percent or dollars, a market type, volume.

Together it reads as one line: *«Bybit → open interest → surge»* or *«16 exchanges → arbitrage → more than 1% net»*.

Three rules worth starting with

If you trade spot. Source — the exchanges you actually have accounts on. Condition — arbitrage. Filter — a threshold at least twice your combined fees. Setting it right at the fee level is pointless: breaking even is not worth the effort.

If you hold positions. Condition — funding, with a threshold on the daily rate. That way you find out when your position started paying noticeably more or less than usual.

If you trade moves. Condition — open interest, surge mode. A sharp inflow into a contract often runs ahead of the price.

What not to do

Setting the threshold too low. A rule at 0.1% will fire constantly, you will stop reading notifications within a day, and the useful ones will drown along with the noise.

One rule for everything. Three narrow rules beat one broad one: a narrow rule is obvious at a glance, a broad one has to be decoded every time.

Subscribing to every exchange when you trade on two. An event from a venue where you have no account is noise, however interesting it is.

What next

Build your first rule in the builder — it walks you through the steps. If a term is unfamiliar, check the glossary: everything there is short and to the point.