Components of the Preview Data Tab

What this is

The Preview Data tab shows a sample of the records the Zeotap CDP has ingested from a source, so you can confirm the shape of what arrived before you map the fields in the Catalogue. The sample is drawn from the last five ingested files, and internal fields added by the platform are rendered in grey so you can distinguish them from the external fields you supplied. Once data begins flowing into a source, the source status changes to Integrated and the Preview Data tab is populated.

Prerequisites

Before Preview Data returns a sample:

The source must be created and its implementation completed for the source type (for example, credentials configured, files uploaded, or the streaming endpoint wired up).
The source must have received at least one file or event. If the source status on the Source Listing page is still Created, no data has arrived yet.

Read the Preview Data table

The Preview Data screen displays a tabular sample of ingested records. Each column corresponds to a field in the ingested file; internal fields added by the platform are shown in grey to separate them from your external fields.

Preview Data tab showing a tabular sample of ingested records with column headers

A well-formed input file with clear, unique headers renders cleanly in the preview. For example, a CSV with the following shape produces four preview columns:

customer_id,email,first_name,purchase_date
1001,[email protected],Alice,2024-11-15
1002,[email protected],Bob,2024-11-16

If any header cell is empty or the file format is invalid, the affected rows are excluded from the sample and raised as entries in View Error Log instead.

Use the Preview Data controls

The Preview Data screen exposes three controls. The table below describes each option and its function.

Sl No.	Option	Description
1	View Error Log	Opens the list of errors detected in the ingested file before Catalogue mapping. Examples include missing column names and file-format issues. For the full list of error scenarios you can encounter on the Preview Data tab, see the Preview Errors reference.
2	Refresh	Redraws the preview using the latest records from the last five ingested files, and displays the last refreshed date and time for reference.
3	Column Filters	Filters the preview to specific columns. Options include selecting all fields, selecting all internal fields, and clearing the current selection.

Column Filters options on the Preview Data tab

Verify the preview is working

Preview Data is functioning correctly when all of the following are true:

The source status on the Source Listing page is Integrated (not Created).
The Preview Data tab shows a tabular sample of records with visible column headers.
Both external columns and internal (grey) columns are present in the sample.
The last-refreshed timestamp updates after you use Refresh.

Why this happens

If the Preview Data tab shows no records, or displays an error message in place of a sample, one of the following causes is at work. The error text below is what the tab surfaces to you; Where to look points to the place in the app that confirms it.

Error string	What it means	Where to look
`No data has been received. Ensure to implement the source correctly and check again later`	The source is created but has not yet received any records	Source Listing page — the source status is Created, not Integrated
Missing column names	The ingested file has empty or duplicate header cells	View Error Log on the Preview Data tab
File-format issue	The uploaded file is not in a supported format	View Error Log on the Preview Data tab

To resolve an empty or errored preview:

Verify that the source implementation is complete for your source type. If the source status remains Created on the Source Listing page, the platform has not received data yet — finish the implementation for that source type and wait for the next ingestion.
Use the View Error Log option on the Preview Data tab to read the specific errors reported for the ingested file.
Correct the source file in your own system — for example, fix missing or duplicate header cells and confirm the file format matches what the source type supports — and re-ingest.
Use Refresh on the Preview Data tab to redraw the sample from the latest ingested files.

If preview remains empty after you re-ingest a corrected file, contact Zeotap support at [email protected]. Include your source ID, the timestamp of the last ingestion attempt, and the error text shown in View Error Log.

FAQ

Why are some columns in the preview shown in grey?

Grey columns are internal fields added by the platform (for example, ingestion metadata). Columns in the standard colour are the external fields from your ingested file. The grey styling exists so you can distinguish the two at a glance.

Why does the preview change every time I refresh it?

The Preview Data tab shows a sample drawn from the last five ingested files. Each Refresh redraws that sample, so the specific rows you see change even though they are all recent records from your source.

Where can I see the full list of preview errors?

The Preview Data tab surfaces the most common errors inline via View Error Log. For the complete catalogue of error scenarios and their meanings, download the Preview Errors reference linked from the controls table above.

Next steps

Sl No.	Option	Description
1	View Error Log	This option enables you to review a list of errors in the data of the dropped file before mapping in the Catalogue. Examples include missing column names, issues with file format and more. For a comprehensive list of error scenarios that you may encounter while working with the Preview Data tab, see the Preview Error Scenarios table below.
2	Refresh	This option enables you to refresh the sample data displayed under the Preview Tab. Upon refreshing, it presents a different set of the latest sample data from the last five ingested files. It also provides the last refreshed date and time for your reference.
3	Column Filters	This option allows you to conveniently filter and view specific columns in the given preview. Use appropriate options to select All fields, select all the internal fields, clear the selections and more as per your requirement.

Preview Error Scenarios

The following table lists the error scenarios that you may encounter while working with the Preview Data tab, along with a description of each:

Preview Error Scenarios	Description
An error occurs if an object contains objects as properties.	This error message is displayed when an object contains another object as one of its properties. The user is prompted to fix the issue to enable mapping.
An error arises when an object or array is not defined in the correct syntax or format.	This error message is displayed when the data within an object or array is not defined in the correct syntax or format. The user is notified about unsupported syntax or format errors in the specified source field and prompted to rectify the issue to enable mapping.
If an object or array of objects contains more properties or keys than the supported number for mapping, an error occurs.	This warning message is triggered when an object or array of objects contains more properties or keys than the supported limit for mapping. Users are informed that the specified source field exceeds the limit of 15 properties per object for mapping, and they are advised to reach out to their Customer Success Manager for an upgrade.
The system encounters an error when a column name is missing in the ingested file.	This error message is displayed when the ingested file lacks a column name. Users are instructed to reupload the file with complete details to resolve the issue.
If the ingested file is in an unsupported file type, an error is triggered.	This error message appears when the ingested file is of an unsupported file format. Users are informed about the unsupported file format and advised to replace it with a supported format.
Duplicate column names in the ingested file lead to an error.	This error message is displayed when the ingested file contains duplicate column names. Users are instructed to reupload the corrected file without duplicate column names to resolve the issue.
An error arises if there is a mismatch in file type between the type mentioned in the source setup and the ingested file.	This error message appears when there is a mismatch between the file type mentioned in the source setup and the ingested file. Users are informed about the mismatch and instructed to correct it to proceed.
If there is a delimiter mismatch between the mentioned delimiter in the source setup and the ingested file, an error occurs.	This error message is displayed when there is a mismatch between the delimiter mentioned in the source setup and the one used in the ingested file. Users are informed about the mismatch and prompted to rectify either the file type or delimiter issue.
The system encounters an error when there is a syntax error or a corrupt record issue.	This message is displayed when the ingested file contains unsupported syntax or format errors. Users are prompted to fix the issue in the file to enable mapping.

​What this is

​Prerequisites

​Read the Preview Data table

​Use the Preview Data controls

​Verify the preview is working

​Why this happens

​FAQ

​Next steps

​Preview Error Scenarios