# Two-way sync

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Whalesync offers true two-way sync. Once set up, you can update data in either connected app and it will sync to the other in real-time.&#x20;

When creating a new Whalesync base, two-way sync is easy to configure. Simply toggle the direction arrows to two-way:

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### Read-Only Fields

{% hint style="info" %}
**Two-way sync is not compatible with "read-only" field types**
{% endhint %}

There are certain field types you cannot sync data into. For example, a formula field cannot be overwritten. We call these "read-only" field types and tag them in the setup flow:

<figure><img src="https://2481481593-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FtLaMDbvbGOow76E8CnqW%2Fuploads%2Fw5zhAFbasXotubFnd0Qi%2FRead%20Only.png?alt=media&#x26;token=67c5dcdf-8408-4310-a097-394a6311f0de" alt=""><figcaption></figcaption></figure>

If you map a read-only field and choose two-way sync, that read-only field will be one-way while the rest of your fields remain two-way.

| Example read-only field types |
| ----------------------------- |
| Formula                       |
| Lookup                        |
| Rollout                       |
| Count                         |
| Created Time                  |
| Last Modified Time            |
| Autonumber                    |