Yeap, just use a "Find Records" action to see if a record already exists with that data, then have a conditional that'll create a new record if it can't find anything.  It'll look something like this:

And this is how the conditional's set up:

Link to base

Is there any way to prevent the new record from being committed in cases where there is already a value for the index field?

Hmm, sorry, I don't understand the question.  Does "committed" mean "saved" in this context?  What's an "index field"?  Are you also creating records with data from a webhook?

Yes, indexed is a field that must be unique within the table and it speeds up retrieval substantiallyl.

See https://www.linkedin.com/pulse/what-indexing-types-rdbms-nishchal-vaishnav-yewxf/

And, no I'm not creating records using webhooks. Just manually in the user interface.

Your #1 best bet for this is to prevent the duplicates from ever appearing in Airtable in the first place.

To do this, you would need to use Fillout’s advanced forms for Airtable because it communicates directly with Airtable and it lets you prevent duplicate form submissions based on any text fields (or email fields) that you specify.

Fillout offers hundreds of features that Airtable’s native forms don’t offer, including the ability to prevent duplicate form submissions, update Airtable records using a form, create custom PDF files from a form submission, accept payments on forms, display Airtable lookup fields on forms, create new linked records on a form, control access to a form via SSO or email domains or a list of email addresses stored in Airtable, perform math or other live calculations on your forms, collect signatures on a form, create multi-page forms with conditional paths, connect a single form to dozens of external apps simultaneously, add CAPTCHAs to your form, and much more.

I show how to use a few of the advanced features of Fillout on these 2 Airtable podcast episodes:

• Using Fillout to create an eSignature approval process with PDF file creation.
• Using Fillout to create an order entry form with line items.

However, if your duplicate records are ALREADY in Airtable, you would need to cleanup the duplicates afterwards through one of these methods:

1. Use Airtable's DeDupe extension to manually merge duplicate records together.
2. Use Airtable’s automations to automatically find & flag duplicate records.
3. Use this Airtable trick that I demonstrate on this Airtable podcast episode: https://www.youtube.com/watch?v=Xc-0Jp6AvAs&list=PLqssva4liHRwHhQIpTXekG8WObEoyC2F1
4. Use a script to automatically merge or delete duplicate records.
5. Use Make’s Airtable integrations to automatically find & flag (or find & delete) duplicate records. If you’ve never used Make before, I’ve assembled a bunch of Make training resources in this thread. For example, here is one of the ways that you could instantly trigger a Make automation from Airtable.
6. You could even collect new records in a secondary table, and then use an Airtable automation to determine whether the new record should be added into the main table where you don’t want the duplicates to appear.

Although, as I mentioned above, the quickest & easiest way to deal with duplicates is to prevent them from ever happening in the first place, which you can do by creating new records with Fillout’s “prevent duplicate submissions” feature.

Hope this helps!

If you have a budget and you’d like to hire the best Airtable consultant to help you with this or anything else that is Airtable-related, please feel free to contact me through my website: Airtable consultant — ScottWorld