Email Verification for Instantly Users: Maximizing Campaign Performance
Instantly has built-in email verification. It runs your prospect list through validation before you launch a campaign, flagging invalid addresses and protecting your sending domains from obvious bounces. For most standard email addresses, this works well enough.
But there is a category of addresses that Instantly's verification cannot fully resolve: catch-all domains. These are domains where the mail server accepts everything, regardless of whether the specific mailbox exists. Instantly labels these as "catch-all" and leaves the decision to you. Send or skip? Without more information, you are guessing.
This is where layering CatchallVerifier on top of Instantly's built-in verification gives you a measurable advantage. You keep the addresses that are actually deliverable, and you remove the ones that will silently fail.
The Catch-All Gap in Instantly
When you upload a prospect list to Instantly and run verification, each email gets categorized. Valid addresses proceed to your campaign. Invalid addresses get filtered out. But catch-all addresses sit in a gray area. Instantly tells you the domain is catch-all but cannot tell you if john.smith@catchall-company.com is a real mailbox or a fabricated address that will silently disappear.
In typical B2B prospect lists, 15-30% of addresses land in this catch-all category. That is a significant chunk of your list. If you discard all of them, you are throwing away potentially 15-30% of your reachable prospects. If you include all of them, you risk sending to non-existent mailboxes, which can increase your bounce rate and damage the domain reputation you have carefully warmed up.
The Layered Verification Workflow
Here is the workflow that maximizes your sendable contacts while maintaining clean deliverability:
Step 1: Upload your prospect list to CatchallVerifier first, before importing into Instantly. Run bulk verification. This gives you three segments: verified valid, catch-all resolved (deliverable), and invalid/undeliverable.
Step 2: Create your import file with only the verified valid and catch-all deliverable addresses. These have been confirmed as addresses that will accept your email.
Step 3: Import into Instantly. Let Instantly's own verification run as an additional safety layer. Any address that passed CatchallVerifier but fails Instantly's check (rare but possible due to timing differences) gets caught here.
Step 4: Launch your campaign with confidence. Every address in your campaign has been double-verified: once by CatchallVerifier for catch-all resolution and once by Instantly's built-in check.
Impact on Campaign Performance
The impact shows up in two places: more contacts and cleaner sends.
More contacts: instead of discarding all catch-all addresses, you add back the ones confirmed as deliverable. On a list of 1,000 prospects with 250 catch-all addresses, CatchallVerifier typically confirms 60-75% as deliverable. That is 150-187 additional contacts in your campaign. At a 5% reply rate, that is 7-9 additional replies from addresses you would have otherwise thrown away.
Cleaner sends: the catch-all addresses you do send to have been verified as deliverable. Your bounce rate stays under 1%, your domain reputation stays healthy, and your warmup investment is protected. Instantly's sending limit recommendations (50 emails per inbox per day) become more efficient when every email has a real recipient.
Protecting Your Warmed Domains
Domain warmup in Instantly typically takes 4-6 weeks. During that time, you are carefully building sender reputation through controlled sending volume and positive engagement signals. A single campaign with a high bounce rate can undo weeks of warmup progress.
Catch-all domains are the most common source of unexpected bounces in warmed Instantly campaigns. The addresses passed basic verification, so they seem safe. But some percentage are not deliverable, and the bounces they generate hit your warmed domain's reputation at a critical time.
CatchallVerifier eliminates this risk. By confirming deliverability before sending, you protect the warmup investment you have already made. Your Instantly domains maintain their reputation, and your sending capacity continues to grow on schedule.
Cost Comparison
CatchallVerifier pricing starts at $35 for 5,000 credits. If you are running 1,000-2,000 prospects per month through Instantly and 20-30% are catch-all, you are looking at 200-600 catch-all verifications per month. That is well within the Starter plan.
Compare that to the cost of a domain reputation crash: 2-4 weeks of reduced deliverability across all campaigns, potential need to warm up a replacement domain (4-6 more weeks), and lost pipeline during the recovery period. The verification cost is a rounding error compared to the potential downside.
Practical Tips
Verify as close to send time as possible. Email data decays, and a catch-all address that was deliverable last month might not be this month. Verify within 48-72 hours of importing into Instantly for best results.
Track your bounce rates by verification source. Keep a record of which addresses were CatchallVerifier-confirmed and which were standard-verified. If one segment shows higher bounce rates, you know exactly where to investigate.
Re-verify between campaign sequences. If you are running a multi-week sequence in Instantly, consider re-verifying contacts between steps, especially catch-all addresses. This catches addresses that decayed between your first and second touchpoints.
The combination of Instantly's sending infrastructure and CatchallVerifier's catch-all resolution gives you the best of both worlds: powerful outreach automation backed by verified, deliverable data. Your campaigns reach more real prospects, your domains stay healthy, and your reply rates improve because every email has a genuine recipient on the other end.
