7.2. Customizing email templates

Email templates are used to generate automatic Registry email communication, such as notifications and warnings.

The templates can me modified through SQL queries. Emails are decomposed into several database tables as follows.


If you customize database tables, remember to examine changes in the database component before upgrading the FRED!

Sometimes we need to edit the templates for ourselves and these changes are added to a database upgrade script, which would overwrite your settings. Therefore you should either backup your current database tables to recover your settings after the upgrade, or adapt the upgrade script directly, so that you don’t lose your settings.

7.2.1. Registry contact information (defaults)

Table: mail_template_default

This table contains Registry contact information (called defaults) grouped in the JSON form.

defaults.* are a data subset that is passed to all email templates.

The parameters are described in the parameter reference.

Example: Registry information JSON
   "defaults.company": "CZ.NIC, z. s. p. o.",
   "defaults.company_cs": "CZ.NIC, správce domény CZ",
   "defaults.company_en": "CZ.NIC, the CZ domain registry",
   "defaults.emailsupport": "podpora@nic.cz",
   "defaults.tel": "+420 222 745 111",
   "defaults.street": "Milešovská 1136/5",
   "defaults.city": "Praha 3",
   "defaults.postalcode": "130 00",
   "defaults.whoispage": "https://www.nic.cz/whois",
   "defaults.authinfopage": "http://www.nic.cz/whois/publicrequest/",
   "defaults.registrarlistpage": "https://www.nic.cz/whois/registrars"

You may have several defaults and associate each with an email template by referencing it in the mail_template.mail_template_default_id attribute.

7.2.2. Email types

Table: mail_type

This table maps an email type name, which is referred to in the Email Parameters Reference, to an id referenced by the mail_template table.

Each email type serves a specific purpose that is built in into the overall functionality of the Registry. For this reason, there is no easy way of adding custom email types at the moment, although you may easily customize the existing types.

It is also possible to disable sending of some email types, see Customizing state-change notifications.

Email types are briefly described in the Email Parameters Reference.

7.2.3. Email composition

An email message is composed of:

  • header fields,

  • a subject,

  • a body,

  • a footer at the end of the body,

  • vCard attachment. Email headers

Table: mail_header_default

This table allows you to preset email header fields, namely:

  • h_from – sender address, From header, e.g. support@registry.com or "Registry Support" <support@registry.com>,

  • h_replyto – address that should be used to reply, Reply-To header,

  • h_errorsto – address(es) for additional notification of delivery errors, Errors-To header,

  • h_organization – sender organization, Organization header,

  • h_contentencoding – content encoding for the Content-Type header, e.g. charset=UTF-8,

  • h_messageidserver – hostname that will be used to generate the Message-ID header, e.g. registry.com, which will result in Message IDs like <39370682.1555751410@registry.com>.

You may have several sets of headers. To associate one with an email template, reference it in the mail_template.mail_header_default_id attribute.

Message-ID generation

A complete Message-ID is composed in the following manner:

<mail_archive.id>.<int(epoch_time)>@<mail_header_default.h_messageidserver> Email footers

Table: mail_template_footer

This table allows you to preset email footers.

An email footer is a component of email content that is added right after the body, typically used to include uniformly-formatted Registry contact information. For example:

Email footer example
<?cs var:defaults.company ?>
<?cs var:defaults.street ?>
<?cs var:defaults.postalcode ?> <?cs var:defaults.city ?>
phone: <?cs var:defaults.tel ?>
email: <?cs var:defaults.emailsupport ?>

You may have several footers. To associate one with an email template, reference it in the mail_template.mail_template_footer_id attribute. Email vCards

Table: mail_vcard

This table contains a unique Registry vCard that is inserted by Mailer to all emails as an attachment.

You may redefine it by updating the row. VCard version is not restricted by the FRED, it is up to you to decide which to use, just consider compatibility with email clients.

vCard example
N:podpora CZ.NIC, z. s. p. o.
FN:podpora CZ.NIC, z. s. p. o.
ORG:CZ.NIC, z. s. p. o.
TITLE:zákaznická podpora
TEL;WORK;VOICE:+420 222 745 111
ADR;WORK:;;Milešovská 1136/5;Praha 3;;130 00;Česká republika
END:VCARD Email template bodies

Table: mail_template

This table contains the core of the email templates, and it has the following attributes:

  • mail_type_id – reference to a mail type id from mail_type,

  • version – version number of the template (see below),

  • subject – a short description of message content for the Subject header,

  • body_template – the main part of a template, see Body templating,

  • body_template_content_type – content subtype of the message (only plain is tested),

  • mail_template_footer_id – reference to a footer id from mail_template_footer,

  • mail_template_default_id – reference to a defaults id from mail_template_default,

  • mail_header_default_id – reference to a headers id from mail_header_default,

  • created_at – template creation timestamp.


We use the convention Local-language subject text / English subject text. Feel free to adapt the local-language text. If you decide to change the optical separator (/), you should use it consistently across the email types.

Content type

The general content type of an email body is always text. The body_template_content_type attribute is a subtype, usually plain, therefore the full content type results in text/plain. Other text subtypes are theoretically possible (such as html, css, xml, csv), although only plain has been tested!


  • The last version is used in generation of new emails.

  • Older versions are kept to regenerate archived messages for viewing in the WebAdmin.

  • When you’re changing any attribute of a mail template, insert a new row with the change and with the version number incremented by 1.


To write upgrades, you may use our database functions get_current_mail_template_version(mail_type_id) and/or get_next_mail_template_version(mail_type_id).

7.2.4. Body templating

In the email body template, we use the convention: local-language (Czech) text first, English text second, and the language variants are optically separated with a couple of newlines.


We recommend to replace the Czech variant of texts with the variant in your local language and keep the English variant for common understanding.

Email bodies are processed with the ClearSilver template system, which takes a template in plain text and passes it a data set to create a resulting email. Each email template is passed a different data set, which depends on the email type. Data (parameters) are passed to a template in a hierarchical form. To traverse the hierarchy, a dot convention is used.

ClearSilver lets you do some basic templating:

  • Output the value of a variable:

    ClearSilver example: Variable
    Handle: <?cs var:handle ?>
  • Control the flow:

    ClearSilver example: Conditional expression
    <?cs if:ident_type != "" ?>
     if:ident_type == "OP"?>Personal ID: <?cs
     elif:ident_type == "PASS"?>Passport number: <?cs
     elif:ident_type == "BIRTHDAY"?>Date of birth: <?cs
     /if ?> <?cs var:ident_value ?>
    <?cs /if ?>
  • Iterate over a list:

    ClearSilver example: List iteration
    <?cs each:item = administrators ?>Administrative contact: <?cs var:item ?>
    <?cs /each ?>
  • And more.

See templates in ClearSilver for complete syntax reference.

For a detailed reference of the passed parameters according to the email type see Email Parameters Reference.