prefix

The prefix operation puts a value in front of the existing one. The original is kept, it just gains something at the start.

How it works

You type the prefix in the operation settings and it is placed at the beginning of the value.

Value:  12345      Prefix: ID-       Result: ID-12345
Value:  797992279  Prefix: +420      Result: +420797992279

Nothing else changes. The operation does not look at what is already there.

Mind the space

The prefix is joined to the value exactly as you typed it, so if you need a space between them, type it.

Bearer with a trailing space gives Bearer eyJhbGci…, which is what an authorisation header needs. Bearer without one gives BearereyJhbGci…, which the other side rejects without saying why.

Trailing spaces are easy to lose when copying from documentation, so this is worth checking when a token that looks right keeps being refused.

Use a condition, or it happens every time

The operation does not check whether the prefix is already there. Run it on a phone number that already starts with +420 and you get +420+420797992279.

That matters whenever the data comes from several sources, or when the same field is filled in by hand. Set the condition so the step only runs when the prefix is missing, for example does not start with the prefix, or is less than a certain length for a phone number.

See Condition Operators and Field value.

The common uses

• Authorisation headers. Adding Bearer to a token, or Basic to encoded credentials. This is by far the most frequent one. See HTTP request.

• Country codes on phone numbers. Your form collects the local number, the advertiser wants it international.

• Identifiers. Advertisers who expect their own IDs to arrive tagged, such as ID- or a partner code.

The other direction

To add something at the end instead, use postfix. To build a value from several fields at once, write them together in the field, as {first_name} {last_name}, rather than chaining prefixes.

Settings

The operation takes one parameter: the text to put in front. Everything else is the source and the condition.