API doesn't respect IS_AFTER filter, issue also reported 3 years ago

Hm as a datapoint I just tried this via Postman with both a GET and a POST and it works fine.  Could you provide some screenshots of your data and the full body of your POST?
 

GET with URL params

https://api.airtable.com/v0/appz6YcyO3dXfqDWV/tblVg5MfRaHq9Cnvt?filterByFormula=IS_AFTER({Date}, '2026-01-25T00:00:00.000Z')

POST with JSON

URL

https://api.airtable.com/v0/appz6YcyO3dXfqDWV/tblVg5MfRaHq9Cnvt/listRecords

Body:

{
    "filterByFormula": "IS_AFTER({Date},'2026-01-25T00:00:00.000Z')"
}

Return: 

{
    "records": [
        {
            "id": "recelxVi6HgvyfFeT",
            "createdTime": "2026-01-27T14:37:26.000Z",
            "fields": {
                "Date": "2026-01-28",
                "Calculation": 1
            }
        },
        {
            "id": "recmCfH2Xhij23hTl",
            "createdTime": "2026-01-27T14:36:29.000Z",
            "fields": {
                "Date": "2026-01-27",
                "Calculation": 1
            }
        }
    ]
}

Here’s my data:

Hey ​@Bruno_Leonardo_ !

Adam's test confirms IS_AFTER works correctly, so the issue is likely in how you're referencing the field. Here are the common problems:

Issue #1: LAST_MODIFIED_TIME() is a function, not a field reference

This won't work:

filterByFormula: "IS_AFTER(LAST_MODIFIED_TIME(), '2026-01-25T00:00:00.000Z')"

LAST_MODIFIED_TIME() is a formula function that returns a value when used inside a formula field. You can't call it directly in filterByFormula.

Solution A: Use the system "Last Modified Time" field

If you've added the "Last Modified Time" field type to your table (not a formula field), reference it like this:

filterByFormula: "IS_AFTER({Last Modified Time}, '2026-01-25T00:00:00.000Z')"

Solution B: If using a formula field

If your {Last Modified} field is a formula field containing LAST_MODIFIED_TIME(), then this should work:

filterByFormula: "IS_AFTER({Last Modified}, '2026-01-25T00:00:00.000Z')"

Debugging Steps:

1. Check field type: Click the field header → "Customize field type" → verify it's either:

   • System field: "Last modified time"
   • Formula field containing: LAST_MODIFIED_TIME()

2. Verify field name: The exact field name matters - check for:

   • Extra spaces: {Last Modified } vs {Last Modified}
   • Case sensitivity: {Last Modified} vs {last modified}
   • Special characters

3. Test the formula directly in Airtable:

   • Create a formula field: IS_AFTER({Last Modified}, '2026-01-25T00:00:00.000Z')
   • Check which records return 1 (true)
   • Those should be the records your API filter returns

Common Issues:

Formula fields with dependencies:

• If {Last Modified} is a formula field, ensure it's calculating correctly
• Formula fields don't always update immediately on record modification
• System "Last Modified Time" fields are more reliable for this use case

Date format:

• Your format looks correct: '2026-01-25T00:00:00.000Z'
• Alternative that also works: '2026-01-25'

Workaround if filtering still fails:

If the filter continues to fail, fetch all records and filter client-side:

const allRecords = await base('TableName').select().all();
const filteredRecords = allRecords.filter(record => {
  const lastModified = new Date(record.get('Last Modified'));
  return lastModified > new Date('2026-01-25T00:00:00.000Z');
});

Test Request:

Can you share:

1. Screenshot of your field configuration (field type)
2. The exact field name as it appears in Airtable
3. Sample values from the {Last Modified} field

This will help identify the exact issue.

Flow Digital - Airtable Gold Services Partner — We're happy to help!

Then my table is corrupted. Thanks for the help, but I’ll have to figure out a workaround for this.