Introduction - Learn the template language in 10 minutes! leverages Jinja2 as our template engine, and we support HTML and Markdown. Jinja is a modern and designer-friendly templating language that is simple, expressive, and widely used.

Our documentation gives an overview of how Jinja2 is integrated into

Jinja2 Syntax

There are a few kinds of delimiters. The default Jinja delimiters are configured as follows:

{% ... %} for Statements

{{ ... }} for Expressions to print to the template output

{# ... #} for Comments not included in the template output

Templating basics

A template is a text document that contains dynamic data replaced by the values passed in as JSON when the template is rendered.

Template variables are enclosed in {{ ... }}

Sample JSON

    "product": "Apple Juice",
    "made_in" : "Singapore"

Jinja2 Template

The product is {{product}}


The product is Apple Juice

jinja2 engine

Comparison operations

Flow control and conditional statements are used to alter the flow of a program Flow control and conditional statements are used to alter the flow of a program.

To check the life span of the product

Sample JSON

    "product": "Apple Juice",
    "life_span": 180,
    "made_in" : "Singapore"

Jinja2 Template

{% if life_span > 160 and life_span < 180 %}
    {{product}} is expiring soon!
{% elif life_span >= 180 %}
    {{product}} has expired!
{% else %}
    It's perfect
{% endif %}


Apple Juice has expired!

{%....%} these are the placeholders from which all the conditions are executed.


{% if %} {% elif %} {% else %}

Comparison operators

Operator Description
== Compares two objects for equality.
!= Compares two objects for inequality.
> Greater than
>= Greater than and equal to
< Less than
<= Less than and equal to

Logical operators

Operator Description
and Returns true if both statements are true
or Returns true if one of the statements is true
not Negate the result, returns false if the result is true


The 'for' 'endfor' is used for looping/iterative purposes.

It's used for repeating a certain set of statements for a particular number of times, then for-endfor is used.

Sample JSON

    "products": ["Apple Juice", "Orange Juice", "Pineapple Juice"]

Jinja2 Template

{% for product in products %}
    <li>{{ product }}</li>
{% endfor %}


    <li>Apple Juice</li>
    <li>Orange Juice</li>
    <li>Pineapple Juice</li>
</ul> Filters/Functions


Filters are special functions that take a data structure or variable in a template and render it in a slightly different format.

We support filters to generate QRCode, barcode and HTML table from a json array.

To use a filter you would typically follow the syntax

{{source_value | filter_name}}.

The delimiters such as {{...}} and pipes | which are used to enclose variables and define filter expressions

Render QR Code

To render a value into a QRCode

{{json_field_or_value | render_qrcode(style="css style")}}

Sample JSON

  "email": "",
  "website": "",

Jinja2 Template

{{website | render_qrcode(style='width: 100px;height:100px;background: white;')}}
QR code for {{website}}


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Render Bar Code

To render a value into a bar code

{{json_field_or_value | render_barcode(type="barcode_type",style="css style")}}

Sample JSON

    "document_id": "889856789012"

Jinja2 Template

{{document_id | render_barcode(type='ean13',style='height: 100px;')}}
Barcode for {{document_id}}


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The followings are the barcode_type

BarCode Type Description
ean8 EAN8
ean13 EAN13
ean EAN13
gtin EAN14
ean14 EAN14
jan JAN
upc UPCA
upca UPCA
isbn ISBN13
isbn13 ISBN13
gs1 ISBN13
isbn10 ISBN10
issn ISSN
code39 Code39
pzn PZN
code128 Code128
itf ITF
gs1_128 Gs1_128

Render Table

Render a json array into a HTML table

{{json_array | render_table(table_class="css class")}}

Sample JSON

    "title": "json list",
    "items": [
        "item_name": "product 1",
        "price": "USD 200.00"
        "item_name": "product 2",
        "price": "USD 300.00"

Jinja2 Template

{{items | render_table(table_class='table')}}


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Render JSON

Render a JSON object into a JSON in the HTML

{{json_object | json}}

Other Useful Functions/Filters

More Functions(Filters) on official website


Want information on the template engine's syntax? Head over to the official Jinja2 website and documentation

A YouTube tutorial is also available for your convenience: - Jinja2 Templating Engine Tutorial by Mr. Rigden