Cutting down on junk emails is a never-ending battle, especially when your team’s constantly collecting addresses from forms, events, and god-knows-where else. If you’re using Nobouncemails to help with this, you’re already a step ahead—but the default settings only go so far. This guide is for folks who want more control: you need custom rules that fit your business, not just generic “is this a valid address?” checks.
Whether you’re wrangling hundreds or thousands of emails, setting up custom validation rules in Nobouncemails can keep your list cleaner and your team happier. Let’s get into the how (and the why it matters).
Why Custom Validation Rules Matter
Out of the box, Nobouncemails will catch most obviously bad emails: typos, fake domains, disposable addresses. That’s good, but it’s not clever. Here’s where custom rules come in:
- Industry-specific needs: Maybe you only want business emails (no Gmail, Yahoo, etc.), or you need to block certain competitors.
- Internal requirements: Maybe your CRM needs emails in a specific format, or you want to filter out known spam traps.
- Better workflows: Custom rules can flag or reject addresses before they land in your system, saving your team manual cleanup.
Bottom line: The default checks are fine for basics. If you care about data quality, you’ll want custom rules.
Step 1: Decide What You Actually Need
Before you start clicking around, get clear on what you want to accomplish. Otherwise, you’ll end up with Frankenstein’s monster: a bunch of rules nobody understands.
Start with these questions:
- Do you only want company email addresses?
- Are there domains you never want (competitors, spam traps, etc.)?
- Does your sales or support team have input? (Ask them—they’ll know the pain points.)
- Are you cleaning lists for marketing, internal use, or both?
Pro tip: Don’t go overboard. More rules = more maintenance, more confusion, and more false positives.
Step 2: Get the Right Access
You’ll need admin or team lead permissions in Nobouncemails to create or edit validation rules for your team. If you’re not sure you have them, check with whoever set up your company’s account.
- Admins: Full control, can set team-wide rules.
- Team Leads: Usually can manage rules for their team, but not always org-wide.
- Regular Users: May only use rules, not create them.
If you’re locked out, don’t waste time guessing—ask your admin for the right permissions.
Step 3: Find the Custom Validation Rule Settings
Nobouncemails isn’t trying to hide this, but it’s not front-and-center either. Once you’re logged in:
- Go to the main dashboard.
- Find your team or workspace in the sidebar.
- Look for “Settings,” then “Validation Rules” (sometimes under “Custom Rules”).
- Click “Create New Rule” or “Add Rule.”
The wording may change depending on your plan, but if you don’t see it, you’re probably on a limited plan or don’t have the right access.
Step 4: Build Your First Custom Rule
Here’s where you actually set up your rule. Nobouncemails gives you a few options:
A. Block or Allow Specific Domains
Use cases: No personal emails, block known spam domains, or allow only company partners.
How to do it:
- Select “Domain” as the rule type.
- Enter domains to block (e.g.,
gmail.com,yahoo.com) or allow (e.g.,yourcompany.com). - Choose what happens: reject, flag, or just warn.
Tips: - If you’re blocking free emails, make sure you don’t accidentally knock out legit addresses (some small businesses use Gmail). - Use “flag” instead of “reject” if you’re not 100% sure—better to review than to lose good leads.
B. Regex (Advanced Patterns)
If you need to get fancy—say, block anything that doesn’t follow a certain pattern—Nobouncemails supports regular expressions (regex).
Example: Only allow emails that start with a first initial and last name: ^[a-z]\.[a-z]+@yourcompany\.com$
Warning: Regex is powerful, but easy to mess up. Test your pattern on sample emails before rolling it out team-wide.
C. Custom Logic (Combo Rules)
Some plans let you combine rules: block certain domains and flag emails with suspicious patterns (like a string of random numbers). This can help catch sneakier spam.
- Combine domain, pattern, and even length checks.
- Set the outcome: reject, flag for review, or auto-approve.
Don’t bother: With ultra-granular rules like “emails must be exactly 15 characters.” Real users don’t care, and you’ll just annoy your team.
Step 5: Test Your Rules Before Inflicting Them on Everyone
This step gets skipped way too often. Don’t just trust that your new rule works. Nobouncemails lets you test email addresses against your rules before going live:
- Use the “Test Rule” button (usually next to Save).
- Try common edge cases: weirdly-formatted but legit addresses, known spam traps, and your own company addresses.
- Ask a teammate to try a few from their side—fresh eyes catch more issues.
Pro tip: Keep track of which emails get flagged or rejected and why. If legit addresses are getting blocked, tweak your rule before it causes headaches.
Step 6: Roll Out the Rules Team-Wide
Once you’ve tested and you’re confident, set the rule to “Active” or “Apply to Team.” Most setups let you:
- Apply rules only to new uploads/entries, or retroactively to old lists.
- Notify your team about the new rule (usually a checkbox or toggle).
Best practice: Start with new entries only. If something goes wrong, you won’t mess up your existing data.
Step 7: Monitor and Adjust (Don’t Set and Forget)
No matter how clever your rules are, you’ll miss something or over-block at first. Here’s what to watch for:
- False positives: Legit emails getting blocked or flagged.
- False negatives: Junk still slipping through.
- Team feedback: Are people complaining, or is it working smoother?
Schedule a quick review after a week or two. Check the logs in Nobouncemails to see what’s being caught or missed. Adjust as needed—don’t be precious about your first attempt.
What Works, What Doesn’t, and What to Ignore
What works: - Blocking obvious junk (disposable domains, spam traps). - Filtering out personal emails for B2B lists. - Simple, well-tested pattern rules.
What doesn’t: - Overly complex rules nobody understands. - Blanket bans without talking to the teams actually using the data. - Relying solely on automated validation—manual review still matters sometimes.
Ignore: - “AI-powered” suggestions that don’t give you control or transparency. If you can’t explain why a rule exists, it’s probably not helping. - Vanity rules (“all emails must be lowercase”—Nobouncemails handles this for you).
Keep It Simple, Iterate Fast
Custom validation rules are meant to help, not create more work. Start with the basics, test with real data, and adjust as your team’s needs change. Don’t try to solve every edge case on day one. If you keep things simple and listen to your team, you’ll spend less time cleaning up messes—and more time actually doing your job.