signed-embedding-parameters.md

title: Parameters for signed embeds

Parameters for signed embeds

Also known as: parameters for standalone embeds.

Parameters are pieces of information that are passed between Metabase and your website via the embedding URL. You can use parameters to specify how Metabase items should look and behave inside the iframe on your website.

Types of parameters

Parameters can be signed or unsigned.

Signed parameters, such as filter names and values, must be added to your server code.

• Editable parameters
• Locked parameters

Unsigned parameters, such as appearance settings, should be added directly to your iframe's src attribute.

• Default values for editable parameters
• Visibility settings for editable parameters
• Appearance settings

Adding a filter widget to a signed embed

You can use editable parameters to add filter widgets to embedded dashboards or SQL questions.

1. Go to your dashboard or SQL question. Make sure you've set up a dashboard filter or SQL variable.
2. Click on the sharing icon > Embed this item in an application.
3. Under Parameters, you'll find the names of your dashboard filters or SQL variables.
4. Select Editable for each parameter that should get a filter widget on your embed.
5. Click Publish to save your changes.
6. Add or update the code on your server to match the code generated by Metabase.

Editable parameters are responsible for passing filter values from the embedded filter widget (displayed on the iframe) through to the filters on your original dashboard or SQL question (in your Metabase).

Note that locked parameters may limit the values that show up in an embedded filter widget.

Populating an embedded filter widget with a default value

If you want to set a default value for your editable filter widget, you can pass that default value to the corresponding parameter name in your iframe's src attribute:

your_embedding_url?parameter_name=value

Let's say your embedded dashboard has a filter connected to an editable parameter called "Breakfast". If you want to set the default value for the "Breakfast" filter to "Scrambled eggs":

your_embedding_url?breakfast=Scrambled_eggs

To specify default values for more than one filter, separate the filters with ampersands (&):

your_embedding_url?breakfast=Scrambled_eggs&lunch=Grilled_cheese

You can set multiple default values for a filter by separating the key=value pairs with ampersands (&):

your_embedding_url?breakfast=Scrambled_eggs&breakfast=Bacon

Hiding filter widgets from a signed embed

If you have a lot of editable parameters (resulting in a lot of filter widgets), you can hide them from your signed embed by adding #hide_parameters to the end of the URL in your iframe's src attribute:

your_embedding_url#hide_parameters=parameter_name

For example, if you want to hide a filter called "Breakfast" from your embedded dashboard:

your_embedding_url#hide_parameters=breakfast

You can hide multiple filter widgets by separating the parameter names with commas:

your_embedding_url#hide_parameters=breakfast,lunch

You can also simultaneously assign a parameter a default value and hide its filter widget:

your_embedding_url?breakfast=Scrambled_eggs#hide_parameters=breakfast

Unsigned parameter syntax

Whenever you're adding a parameter to the embedding URL in your iframe's src attribute, note that:

• Parameter names are lowercase.
• Parameter values are case-sensitive (the values must match your data).
• Spaces should be replaced by underscores.

Restricting data in a signed embed

If you want to restrict the data that's displayed in an embedded dashboard or SQL question, you can set up a locked parameter. A locked parameter filters the data in a dashboard or SQL question before the results are displayed to the end user in a signed embed.

1. Go to your dashboard or SQL question. Make sure you've set up a dashboard filter or SQL variable.
2. Click on the sharing icon > Embed this item in an application.
3. Under Parameters, you'll find the names of your dashboard filters or SQL variables.
4. Select Locked for each parameter that you want to restrict your data with.
5. Optional: select a value under Preview locked parameters to see what the restricted data looks like.
6. Click Publish to save your changes.
7. Add or update the code on your server to match the code generated by Metabase.

You can use locked parameters to display filtered data based on attributes captured by your web server, such as a username or a tenant ID. For more examples, see the reference apps repo.

Locked parameters will apply the selected filter values to your original dashboard or SQL question, but they won't be displayed as filter widgets on your embed. Locked parameters may also limit the values that are shown in your editable filter widgets.

Updating a locked parameter

Things to keep in mind if you need to make changes to your locked parameters.

Include all locked parameters in your server code

Once you publish a chart or dashboard with a locked parameter, you must include the name of the locked parameter in your server code. If you forget to do this, the logs will remind you with a message like this: You must specify a value for :parameter in the JWT.

Make sure the filter name matches the locked parameter name

If you change the name of a query builder filter that's used as a locked parameter, make sure to update the parameter's name and value(s) in your server code as well. You don't have to do this if your locked parameter is connected to a SQL variable.

Multiple locked parameters or multiple values

The values for the locked parameter in your server code should match your filter's values exactly. The best way to set multiple locked parameters, or pass multiple values to a locked parameter, is to pick a filter value under Preview locked parameters and preview the server code generated by Metabase.

Locked parameters on dashboards with SQL questions

If your locked parameter is linked to a dashboard filter that's in turn linked to a SQL question, you'll only be able to choose a single value for your locked parameter.

For example, let's say you have a dashboard filter called "Breakfast" with the values "Scrambled eggs", "Bacon", and "Waffles". If the "Breakfast" filter is linked to any SQL questions on the dashboard, you'll only be able to choose one of "Scrambled eggs", "Bacon", or "Waffles" for a locked parameter linked to the "Breakfast" filter.

Customizing the appearance of a signed embed

You can change the appearance of an embedded item by adding hash parameters to the end of the URL in your iframe's src attribute.

For example, the following embedding URL will display an embedded item in dark mode, without a border, and with its original title:

your_embedding_url#theme=night&bordered=false&titled=true

You can preview appearance settings from your question or dashboard's embedded appearance settings.

Parameter name	Possible values
bordered	true, false
titled	true, false
theme	null, transparent, night
font¹	font name
hide_download_button²	true, false

¹ Available on paid plans.

² Available on paid plans and works on questions only (not dashboards).

Maximum request size

The maximum length of a signed embedding URL (including all parameters) is the value of your MB_JETTY_REQUEST_HEADER_SIZE environment variable. The default is 8192 bytes.

If your signed embedding URL exceeds the maximum header size, you'll see a log message like URI too long. You can update the environment variable to accept larger headers. If you're using a proxy server, you may need to set a corresponding property on the server as well.

Further reading

• Signed embedding documentation.
• Strategies for delivering customer-facing analytics.
• Publishing data visualizations to the web.