> For the complete documentation index, see [llms.txt](https://docs.augelab.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.augelab.com/function-blocks/blocks-reference/data-logic/data-operations/parse-data-dictionary.md).

# Parse Data Dictionary

This function block extracts a single value from a dictionary provided as text or as a dictionary object. It helps you pick a key from the incoming data and outputs the associated value for use in the rest of your system.

## 📥 Sockets as inputs <a href="#inputs" id="inputs"></a>

`Input Dictionary (String)`\
Provide a JSON-formatted string or an already-parsed dictionary. Example format shown in the UI helps you prepare the input.

## 📤 Sockets as outputs <a href="#outputs" id="outputs"></a>

`Output Data`\
The value corresponding to the key selected in the dropdown. If the selected key is not present or no input is provided, output may be empty.

## 🕹️ Controls <a href="#controls" id="controls"></a>

`Select key from input data dict` Dropdown to pick which key from the incoming dictionary you want to extract.

`Input example / helper text` Informational text showing an example input format (e.g. {"name": "product", "id": 345}) to guide you.

## 🎯 What this block does <a href="#features" id="features"></a>

* Automatically reads incoming JSON-like text or dictionary inputs and exposes the available keys.
* If the available keys change, the dropdown updates so you can select the new key.
* Outputs only the selected value (not the whole dictionary), making it easy to feed single values downstream.

## 📝 How to use <a href="#usage" id="usage"></a>

1. Feed a JSON string or dictionary into the `Input Dictionary (String)` socket.
2. Open the `Select key from input data dict` dropdown and choose the key whose value you need.
3. The chosen value will appear on the `Output Data` socket for other blocks to use.

## ⚙️ Running behavior <a href="#evaluation" id="evaluation"></a>

When the block runs it checks the incoming input. If it is a string representing a dictionary it parses it and lists the top-level keys in the dropdown. When you choose a key the block outputs the associated value on `Output Data`. The dropdown list updates automatically whenever new input presents a different set of keys.

## 💡 Tips and Tricks <a href="#tips-and-tricks" id="tips-and-tricks"></a>

* Use with communication blocks to process incoming messages:
  * Connect `REST API - Get` (use its `Response`) to parse API responses.
  * Connect `MQTT Subscribe` (use its `Data`) to extract fields from incoming messages.
* Use with storage/flow blocks:
  * Feed `Data Read Local` or `Data Read Global` outputs to parse stored dictionaries.
  * Pair with `Data to JSON` when you need to convert structured data into a string first, then parse a specific key here.
* Save or inspect results:
  * Send extracted `Output Data` to `CSV Export` or `Image Logger` (if saving metadata) for logging.
  * Use `Debug Input` to quickly inspect the parsed value during development.
* Validation hint: If you are testing manually, try sending a value from `String Input` to confirm the dropdown populates correctly.

## 🛠️ Troubleshooting <a href="#troubleshooting" id="troubleshooting"></a>

* Nothing appears in the dropdown: make sure the input is a valid JSON string or a dictionary object and that it contains top-level keys.
* Invalid input format: provide JSON-style text (keys and strings with quotes) or a proper dictionary from upstream blocks.
* Selected key yields empty output: confirm that the key exists in the current input dictionary and that you selected the correct dropdown entry.
* Keys change but dropdown does not refresh: feed a new dictionary (or re-evaluate the upstream block) so the block can detect the new key set and update the list.