"Compose" ("Verfassen") in Power Automate: what the block is really for

The action "Verfassen", Compose in the English original, is a temporary store: it takes in any value, a text, a number, an entire data object, or the result of a formula, and makes it available to all following steps as output. It does nothing more than that, and that is exactly what makes it so useful. The German translation misleads many people, because the block has only a marginal connection to composing text. As of: July 2026.

What is "Verfassen" used for in practice?

• Calculate a value once, use it multiple times: a formula, for example a formatted date, is calculated once in the Compose and then reused in five steps, instead of maintaining the formula five times.
• Make intermediate results visible: when troubleshooting, Compose is the window into the flow. A Compose with the value in question shows exactly what arrived at that point in the run history.
• Assemble data: texts, JSON objects, or HTML for an email can be assembled in the Compose from dynamic content, cleanly separated from the send step.
• Maintain constants: a Compose at the start of the flow with a recipient list or threshold value turns later adjustments into a one-click job.

"Verfassen" or variable: what is the difference?

The decisive difference: a Compose is immutable, its value is fixed after the step. A variable ("Initialize variable" and its siblings), on the other hand, can be changed over the course of the flow, for example counted up in a loop or filled step by step. The rule of thumb is: anyone who only wants to record or calculate a value uses Compose, it is lighter and faster. Anyone who needs to change a value along the way needs a variable. A common pitfall here: variables must always be initialized at the top level of the flow, not inside a loop or condition, Compose has no such restriction.

A look at the output

Following actions access the value of a Compose step via its "output", in formulas via outputs with the name of the step. That is why it pays to rename Compose steps immediately: "Verfassen 7" becomes "Recipient list", and the flow stays readable even a year later. Our Power Automate consulting, and for the related evergreen topic of the German interface it is worth looking at "Apply to each" explained in German.

Frequently asked questions about "Verfassen"

Why is Compose called "Verfassen" in German?

The German Power Automate interface translates the English action names literally, Compose became "Verfassen". What is meant is assembling a value, not writing text. Anyone searching for solutions should therefore always also search for the English term Compose, most guides online use it.

Can "Verfassen" store multiple values at once?

Yes, a Compose can hold a complete object or array, for example a self-built JSON with multiple fields. You then access individual parts via a formula. For structured data that is later to be read out selectively, the combination of Compose and "Parse JSON" is the usual pattern.

Do many Compose steps slow down my flow?

Practically not, Compose is one of the lightest actions there is and is noticeably faster than variable operations. The only thing to keep in mind is the action allowance of the license: a Compose also counts as an action, and in large loops this adds up. So within loops, use it only where it is really needed.