Bulk Zalo Number Checker: CSV Upload and Result Export Guide
The CSV is not a way to get numbers into the tool. It is the deliverable, and on a Zalo file the country column is the main key. Drop it and the export...
Ethan works on phone-number normalization, E.164 formatting, country-code rules, carrier metadata, and line-type detection. His editorial work turns verification signals into practical workflows for CRM cleaning, SMS preparation, lead review, and bulk data operations.
View full author profile →The CSV is not a way to get numbers into the tool. It is the deliverable, and on a Zalo file the country column is the main key. Drop it and the export becomes a list of numbers with no market story, and someone will run a campaign off a meaningless percentage. Bulk Zalo Number Checker is the ZelNum page that supports this job: Zalo Number Checker.
Quick answer
Build the CSV with one phone number per row, a stable record ID, and a filled country column. Upload, check, and export with the on-Zalo status per row. Read the export by country, not as one number, because Zalo’s reach is a Vietnam story and the rest of the file is a different conversation.
Build the CSV so it survives the round trip
- One number per row. No notes column inside the list, no merged cells, no hidden rows.
- Keep
record_idas text. A CRM id that looks numeric can lose leading digits in a spreadsheet. - Keep the country column, filled. This is the field that makes the export readable.
- Leave duplicates in. The duplicate count is a signal in itself, and the checker reports status per row.
The two-market read
A mixed file comes back with two very different shapes:
| Part of the file | Typical on-Zalo share | What it means |
|---|---|---|
| Vietnam rows | 78-84% | Zalo is the campaign channel. |
| Regional rows | 3-6% | Zalo is not the channel; route to SMS. |
(These ranges are illustrative, not a product performance claim.)
A flat overall number hides this. The export should show the country split explicitly, either as a column or as separate result segments, so the reader cannot miss it.
What the export should contain
| Column | Why it is there |
|---|---|
record_id |
Joins the result back to the source file. |
input_number |
The original value, unchanged. |
normalized_e164 |
The value in a comparable form. |
on_zalo |
The channel signal this check exists to produce. |
country_or_region |
The key that decides how to read the row. |
status / reason |
The routing decision and why. |
checked_at |
The timestamp that makes re-checks comparable. |
Routing the export
- Vietnam rows with on-Zalo → the Zalo workflow.
- Vietnam rows valid but not on Zalo → SMS fallback.
- Regional rows → SMS or another channel, regardless of on-Zalo status.
- Invalid → repair if obvious, otherwise suppress.
- Unknown → hold for retry.
Route in the file, not in your head. The whole point of the export is that each row carries its decision.
Mistakes to avoid
- Dropping the country column to save space. That is the column that gives the file its meaning.
- Reading one percentage for the whole file. The Vietnam figure is the campaign decision; the regional figures are the warnings.
- Treating the export as a one-time result. Without a re-check schedule, the file quietly goes stale.
FAQ
Why is the country column the main key for Zalo?
Because Zalo’s reach is concentrated in Vietnam. The on-Zalo signal means one thing in the Vietnam rows and another in the regional rows, and the country column is what separates them.
What if my file is all Vietnam numbers?
Then the country column is still worth keeping for consistency, but the market read is simpler: the on-Zalo share is directly the campaign signal.
Can I re-check the same CSV?
Yes. Keep the same record IDs and compare the on-Zalo status between runs. The movement between runs is the report that matters.
What do I do with unknown rows?
Hold them for retry and re-check. Unknown is a queue, not a dead end, on a Zalo file.
Should I merge duplicates before uploading?
No. Leave them in and let the checker report per row. The duplicate count is data.
Related ZelNum pages
- How to Use Zalo Number Checker for Bulk List Checks for the step-by-step workflow.
- Zalo Number Checker Use Cases for how different teams read the same export.