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# Global ID 

Global ID is a mechanism that allows you to map and synchronize values across multiple Option Sets.
# 1. Mapping values between different Option Sets
Global ID allows values from different option sets to be linked so they automatically sync. For example, you have two option sets:\*\* Upper part \*\*and **Lower part.**

Each option set contains corresponding values (for example, matching top and bottom designs).
* When a customer selects value 1 in the **Upper part,** then the **Lower part** will automatically switch to value 1
* When the customer changes the selection in **Lower part** and **Upper part** updates automatically as well

In order to do it, first you select the two option sets Upper part and Lower part, then click  **Edit Global ID**

![Edit Global ID](https://storage.crisp.chat/users/helpdesk/website/-/b/3/c/1/b3c1fc6f21f6e800/image_1uhnzvf.png)en enter any value,  (for example: `1`) and Save. All values that share the same Global ID (e.g. 1) will be treated as linked. When one linked value changes, all other values with the same Global ID will update automatically.

![Set up global ID](https://storage.crisp.chat/users/helpdesk/website/-/b/3/c/1/b3c1fc6f21f6e800/image_mzxpzm.png)
# 2. Using Index with Global ID
In addition to direct value mapping, Global ID can be combined with **Index** to control conditional content display. For example, you have an option set **Choose Month** (January, February, March, April, etc.) and an option set **Choose Quote** (a/an). So the display requirement here will be show **“I’m a”** for most months and show **“I’m an”** for April, August, and October. Set up logic will be:
* **Choose Month** controls the logic using Index
* **Choose Quote** acts as a reference option set and does **not** require Index

### a. Step 1: Assign Index to the Month values
Set Index on **Choose Month** only:
* Months that use “a” → Index = 1 
* Months that use “an” → Index = 2

![Set up index](https://storage.crisp.chat/users/helpdesk/website/-/b/3/c/1/b3c1fc6f21f6e800/image_16tjsg5.png)
### b. Set Global ID for both option sets
Assign the same **Global ID** (for example: `1`) to:
* **Choose Month**
* **Choose Quot**e 
\*Note: No Index is required on the **Choose Quote** option set.

![](https://storage.crisp.chat/users/helpdesk/website/-/b/3/c/1/b3c1fc6f21f6e800/image_zzyrv9.png)
### Result
* When a customer selects a month with **Index = 1**, the system automatically displays **“a”**
* When a customer selects a month with **Index = 2**, the system automatically displays **“an”**
The **Choose Quote** option set dynamically follows the Index value from **Choose Month**, acting as a linked reference.
# When should you use Global ID?
Use Global ID when you need to:
* Synchronize values across multiple option sets
* Drive one option set using the Index of another
* Build conditional display logic without complex conditions