Learn the concepts and best practices to get the most out of Kestra.
Flowable Tasks
Flowable tasks control the orchestration logic — run tasks or subflows in parallel, create loops and conditional branching.
Runnable Tasks
Runnable tasks are data processing tasks incl. file system operations, API calls, database queries, etc. These tasks can be compute-intensive and are processed by workers.
Revision
Flows are versioned by default. Whenever you make any changes to your flows, a new revision is created. This allows you to rollback to a previous version of your flow if needed.
Secret
Secret is a mechanism that allows you to securely store sensitive information, such as passwords and API keys, and retrieve them in your flows.
Pebble Templating Engine
Pebble is a Java templating engine inspired by Twig and similar to the Python Jinja Template Engine syntax. Kestra uses it to dynamically render variables, inputs and outputs within the execution context.
Blueprints
Blueprints is a curated, organized, and searchable catalog of ready-to-use examples designed to help you kickstart your workflow.
Backfill
Backfills are replays of missed schedule intervals between a defined start and end date.
Task Runners
Replay
Replay allows you to re-run a workflow execution from any chosen task run.
Expression
Kestra's expressions use Pebble Templating along with flow's execution context to render various flow and task properties.
Expression Types
There are many ways to use expressions in Kestra. This page will guide you through different types of expressions.
Expression Usage
This page summarizes the main syntax of filters, functions, and control structures available in Pebble templating.
Filter
Filters can be used in expressions to perform some transformations on variables such as formatting a date, converting a string to uppercase, or joining a list of strings.
JSON Filters
JSON filters are used to manipulate JSON objects, often API responses.
Numeric Filters
Numeric filters are used to format numbers or convert strings to numbers.
Object Filters (Maps, Arrays and More)
Object filters help you manipulate maps and arrays.
String Filters
String filters are used to manipulate strings i.e. textual data.
Temporal Filters
Temporals filters are used to format dates and timestamps.
YAML Filters
YAML filters are used to turn YAML strings into objects.
Function
Functions can be called to generate content. Functions are called by their name followed by parentheses () and may have arguments.
Operator
Operators are used to perform logical operations within templated expressions such as comparing values and performing arithmetic operations.
Tag
Tags are used to control the flow of the template. They are enclosed in {% %}.
Test
Tests are used to perform logical operations within templated expressions such as checking if a variable is defined or if a variable is empty.
Deprecated handlebars
Handlebars are deprecated and superseded by Pebble. These functions will be removed soon and are disabled by default.