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Tera syntax quick reference

Use this guide to build and troubleshoot Tera expressions in Notification Center. Tera syntax powers dynamic templating for connectors, presets, and routing rules.

Basic syntax

Type	Example	Description
Variable	{{ alertDef.name }}	Displays the value of a variable.
Conditional	{% if alert.status == "Triggered" %}...{% endif %}	Adds logic to control output.
Loop	{% for i in alert.groups %}{{ i.priority }}{% endfor %}	Iterates through a list.

Comparison operators

Operator	Example	Description
==	alert.highestPriority == "P1"	Equal to
!=	alert.status != "Resolved"	Not equal
> , < , >= , <=	alert.value > 80	Greater/less comparisons

Logical operators

Operator	Example	Description
and	alert.highestPriority == "P1" and alert.status == "Triggered"	Both must be true
or	alert.highestPriority == "P1" or alertDef.priority == "P2"	Either can be true
not	not alert.status == "Resolved"	Negates a condition

String tests

Function	Example	Result
is starting_with()	alertDef.name is starting_with("CPU")	true if the name begins with CPU
is containing()	alertDef.description is containing("latency")	true if the text includes the word
is matching()	alertDef.name is matching("(?i)^cpu")	Regex match

Filters

Filters transform or format values. Apply them with a pipe (|).

Filter	Example
default	{{ alert.highestPriority | default(value="P3") }}
date	{{ alert.timestamp | date(format="%Y-%m-%d %H:%M") }}
json_encode	{{ get_context() | json_encode(pretty=true) }}
json_escape	{{ alert.groups | json_escape }}
lower	{{ alertDef.name | lower }}
replace	{{ alertDef.name | replace(from=" ", to="_") }}

Boolean conditions in routing rules

Routing rule conditions must evaluate to true or false.
Do not wrap conditions in {{ }}, enter only the expression.

Example	Description
alert.highestPriority == "P1"	Routes only P1 alerts
alertDef.name is containing("CPU")	Routes alerts with “CPU” in the name
alertDef.entityLabels.environment == "prod"	Routes based on environment
true	Always triggers

Note

• Use {{ get_context() | json_encode(pretty=true) }} to print all available variables.
• Wrap optional values with default() to avoid errors.
• Missing variables cause expressions to evaluate to false.
• Keep expressions readable: avoid complex logic in message fields.

Next steps

Build, validate, and troubleshoot Tera templates in Tera usage and troubleshooting.