Extract a value without writing a regular expression

A pointer extracts a value that Extraction does not find on its own: a house identifier, a token in a format that is yours alone, or one of two codes present in the same message.

You do not write a regular expression. You select the value in a real message, and the platform writes the pattern.

Create a pointer

1. In the inbox view, open a message that contains the value.
2. Select the value with the mouse. The editor proposes several patterns, ranked, each with the reason it sits there.
3. Pick a pattern, name it, save it.

The pointer then applies to every new message in that inbox, and you read it back under the key you named:

message.extract.orderCode;

Choose the strategy

Strategy	The pattern you get	When to pick it
context	anchored on the preceding words	The recommended default. Survives a layout redesign
context-strict	anchored on four words	The message holds several values of the same shape
shape	\b(\d{6})\b	The shape is unique in the message
loose	\b(\d{5,7})\b	The sender sometimes strips leading zeros
literal	the exact value	A string that never changes

Patterns that capture exactly your selection, and only once, come first.

Take context if you are unsure: it anchors on the last literal words preceding the value. A layout changes often, “your confirmation code is” much less so.

Read the test result before saving

Before saving, the editor runs the pattern against your twenty most recent messages and shows how many yield exactly one capture. Read that number: a pattern that works on the message in front of you and fails on the ten before it is the one that will break your CI run at three in the morning.

The test is executed by the service that receives your messages, so by the same regular expression engine as production. The editor’s green tick and the real behaviour cannot diverge.

What the engine refuses

Patterns are compiled by RE2. Two constructs do not exist, and the editor tells you before saving rather than on the first message received:

• lookahead (?=…) and (?!…);
• backreferences \1.

Almost everything you would do with a lookahead can be rewritten by anchoring on context, which context already does.

Write the pattern by hand

The pattern field stays editable if you would rather write it yourself. What you put there goes through the same check: compiled by RE2, then run against your twenty most recent messages. No path skips the test.