The Scenario
You are a SaaS ops manager. Your product uses Postmark's inbound email processing. Over the past two weeks, the same 50 spam domains have been hammering your inbound address with junk that creates noise in the support queue and occasionally triggers automated responses to garbage senders.
The domains are in an Excel workbook, column A of the 'Spam Domains' tab. You need Postmark inbound block rules for all 50 of them before the next batch hits Monday morning. The rule IDs need to go into column B for future reference.
The slow version:
- Look up the Postmark inbound rules API
- Write a loop, call the API once per domain, handle errors
- Copy rule IDs from the API responses into the workbook
- Realize 3 domains were formatted as full email addresses, not bare domains
- Fix and re-run
- An hour of plumbing for a list that should have taken five minutes.
The fast version is one prompt.
The Easy Way: One Prompt in SheetXAI
SheetXAI is an AI agent inside your Excel workbook that reads the domain list and creates the Postmark inbound rules for you, with rule IDs written back per row.
Open the SheetXAI sidebar and type:
For each domain in column A of the 'Spam Domains' tab, create a Postmark inbound rule to block that domain and write the returned rule ID into column B. Write 'Error: [reason]' if a row fails.
SheetXAI reads all 50 domains, calls the Postmark inbound rules create endpoint for each one, and writes the rule IDs back. Column B is your reference log.
What You Get
Fifty inbound block rules created in Postmark, with rule IDs in column B:
- Rule IDs for successful creates — reference these if you need to remove a rule later
- Error reasons for any failures — specific enough to fix and retry
- The workbook is the block rule inventory for the inbound stream
You never opened the Postmark dashboard.
What If the Data Is Not Quite Ready
Spam domain lists are messy by definition.
When some rows are full email addresses instead of bare domains
The list was assembled from bounce logs and some entries look like spam@malicious.example.com.
For each row in column A of the 'Spam Domains' tab: if the value contains an '@' symbol, extract just the domain part. Then create a Postmark inbound rule for each domain and write the returned rule ID into column B.
When the list has duplicates from multiple team members
The same domain appears in rows 12 and 38 because two support reps added it independently.
Deduplicate column A of the 'Spam Domains' tab, keeping the first occurrence. Then create a Postmark inbound rule for each unique domain and write the rule ID into column B.
When you want to check which domains already have a block rule
Some may have been added manually to Postmark last week.
List all existing Postmark inbound rules and check column A of the 'Spam Domains' tab against the returned rule patterns. Write 'Already blocked' in column B for any domain that already has a rule. For the remaining rows, create new Postmark inbound rules and write the returned rule ID into column B.
When you need dedup, format normalization, duplicate check, and rule creation all in one shot
The list is a mess and Monday morning is close.
In the 'Spam Domains' tab: for any row in column A containing '@', extract the domain. Remove duplicate domains, keeping the first occurrence. Check each domain against existing Postmark inbound rules. Write 'Already blocked' in column B for domains that already have a rule. For the rest, create a new Postmark inbound block rule and write the returned rule ID into column B. Write 'Error: [reason]' for any that fail.
The pattern: instead of cleaning, checking, and creating as three separate steps, you ask for all of it in one prompt.
Try It
Get the 7-day free trial of SheetXAI and open your spam domain list workbook, then ask it to push the block rules to Postmark. The Postmark integration is included in every SheetXAI plan. For related workflows, see how to manage Postmark suppression lists in Excel or the Postmark in Excel overview.