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
`==`	`alertDef.priority == "P1"`	Equal to
`!=`	`alert.status != "Resolved"`	Not equal
`>` , `<` , `>=` , `<=`	`alert.value > 80`	Greater/less comparisons

Logical operators

Operator	Example	Description
`and`	`alertDef.priority == "P1" and alert.status == "Triggered"`	Both must be true
`or`	`alertDef.priority == "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 {{ alertDef.priority | 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
alertDef.priority == "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

Dynamic Templating: Learn how Tera expressions apply across connectors, presets, and routing rules
Routing Rules: Use boolean conditions and string tests in routing expressions
Preset Setup for Alerts Embed Tera expressions into alert-specific message templates

Previous Dynamic Templating

Next Tera Usage

Filter	Example
`default`	`{{ alertDef.priority \| 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="_") }}`

Example	Description
`alertDef.priority == "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