---
title: Using data to specify dictionaries
summary: null
url: https://www.fastly.com/documentation/reference/tools/fiddle/data
---

Compute fiddles support specifying data to expose to your application as [dictionaries](https://www.fastly.com/documentation/guides/full-site-delivery/dictionaries/about-dictionaries). The data provided in the fiddle settings can be read in the same way as any other dictionary, via the dedicated interfaces in our Compute SDKs:

[Try it in Fastly Fiddle](https://fiddle.fastly.dev/3461c353)

> **HINT:** VCL fiddles do not yet support dictionaries, but you can write [VCL tables](https://www.fastly.com/documentation/reference/vcl/declarations/table) directly in the **INIT** field. In the Compute platform, dictionary lookups trigger a platform behavior at runtime, while in VCL services dictionaries are rendered into the VCL source code as [tables](https://www.fastly.com/documentation/reference/vcl/declarations/table/) at compile time. As a result, you can effectively simulate a dictionary in a VCL fiddle by using a `table` declaration.

## Populating dictionary data

Click the 'Data' option under the request configuration to open the data editor.

![Location of the data menu in Fiddle](/img/data-ui-1612w.png)

Type your data in YAML format, under a top level `dictionaries:` key. Keys under the top level `dictionaries` key are the names of dictionaries, and within each dictionary, specify key-value pairs to populate the dictionary items.

```yaml
dictionaries:
  config:
    rate_limiting: "on"
    banned_geos: "de:ru:au:jp"
  redirects:
    /demos: "/content/sections/d952gab58gf4wdv"
```

Currently the only valid top-level key within the data field is `dictionaries`.

## Querying dictionaries from edge code

The Compute platform offers a dictionary interface in all supported SDKs. Code examples of dictionary lookups are included on our language specific overviews. See [choosing a language](https://www.fastly.com/documentation/guides/compute/getting-started-with-compute/#choose-a-language-to-use) in the Compute onboarding guide.