The Scenario
You are a growth engineer. You have spent three months building out a robust attribution pipeline. The problem: your identity graph has a gap.
During a marketing campaign last quarter, the site used anonymous visitor IDs before signup. After signup, the platform assigned a known user ID. The link between the two — the alias — was never sent to Segment. That means every acquisition cohort from that quarter shows as anonymous in Segment's funnel, and anonymous users do not get attributed to campaigns.
You have a Google Sheet with 1,200 rows of the paired IDs: column A has the anonymous visitor ID from the pre-signup session, and column B has the known user ID after account creation.
You need all 1,200 pairs aliased in Segment so the full user journey is stitched before the next attribution report.
The slow version:
- Write a script to call Segment's alias endpoint per row
- Handle auth, rate limits, retries
- Wonder partway through why 40 rows are erroring and there is no log to check
- Run it twice by accident, aliasing some IDs in both directions.
The fast version is one prompt.
The Easy Way: One Prompt in SheetXAI
SheetXAI reads the sheet and sends the alias calls, so you do not have to write the script.
Open the SheetXAI sidebar and type:
Send a Segment alias call for every row in the Identity Stitching sheet using the anonymous ID from column A as the previous ID and the known user ID from column B as the new ID. Write DONE or ERROR into column C per row.
SheetXAI reads all 1,200 rows, calls Segment's alias endpoint for each pair, and writes result status back to column C.
What You Get
1,200 Segment alias calls with row-level status in column C:
- DONE for every pair Segment accepted
- ERROR for any row that failed, with the reason
- Full journeys stitched — pre-signup sessions in Segment now link to known user IDs, and campaign attribution flows through to conversion events
The alias direction matters. SheetXAI sends the anonymous ID as previousId and the known user ID as userId, which is the correct direction for Segment's identity graph. You do not have to remember which field is which.
For any rows that come back with ERROR, filter by ERROR in column C, inspect the IDs, and ask SheetXAI to resend just those rows.
What If the Data Is Not Quite Ready
Identity stitching sheets always have edge cases. SheetXAI handles them and the alias calls in the same prompt.
When some anonymous IDs look like known user IDs
A few rows have the columns swapped — the known user ID is in column A and the anonymous ID is in column B.
For rows where column A starts with a numeric prefix (e.g., "usr_") and column B looks like an anonymous visitor ID (starting with "anon_"), swap the columns before sending. For all other rows, use column A as previousId and column B as userId. Send a Segment alias call per row and write DONE or ERROR into column C.
When some pairs are duplicates
The export was pulled twice and some ID pairs appear twice in the sheet.
Deduplicate the Identity Stitching sheet by the combination of column A and column B, keeping one occurrence per unique pair. Then send a Segment alias call for each deduplicated pair using column A as previousId and column B as userId. Write DONE or ERROR into column C.
When you want to alias only pairs where the known user ID was created in the last quarter
You are fixing attribution for last quarter only. Older pairs are out of scope.
Filter to rows where the known user ID in column B was created in Q1 2026 (you can check the creation date by looking up column B against the Users tab, column C). Send a Segment alias call for each matching pair using column A as previousId and column B as userId. Write DONE or ERROR into column C.
When you need deduplication, ID direction validation, and alias calls all in one pass
The sheet has duplicates, some columns are swapped, and some anonymous IDs are blank.
Remove any rows where column A is blank. For rows where the anonymous ID pattern (starting with "anon_") is in column B instead of column A, swap the columns. Deduplicate by the pair of column A and column B, keeping one occurrence. Then send a Segment alias call for each remaining row using column A as previousId and column B as userId. Write DONE or ERROR into column C.
The pattern: the data cleanup and the API calls happen in one instruction, not in two separate steps with a manual review in between.
Try It
Get the 7-day free trial of SheetXAI and open any sheet with anonymous-to-known ID pairs, then ask it to alias them in Segment. The Segment integration is included in every SheetXAI plan. For related workflows, see how to bulk-send historical identify calls or the Segment in Google Sheets overview.