Here’s a number nobody puts on a landing page: industry deliverability reports put cold email success rates lower in 2026 than two years ago, mostly because Google and Microsoft keep tightening bulk-sender rules at Gmail and Outlook. You can write great copy, target the right people, and still land 60% of it in spam if your sending setup is sloppy.
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I run a newsletter on Buttondown and handle outreach for a couple of projects, so deliverability isn’t theoretical for me. An inbox placement tool won’t fix a bad offer, but it will tell you within a day whether your domain warmup, SPF/DKIM setup, or sending volume is the thing quietly killing your reply rate. Here’s how the main players compare on price, and which situations each one actually fits.
What cold email deliverability tools actually do
Most of these tools do some mix of three jobs: warm up new domains by simulating natural sending activity, monitor whether your emails land in the primary inbox, promotions tab, or spam, and alert you before a blacklist issue or DNS misconfiguration wrecks a campaign. They don’t send your real outreach. Smartlead, Instantly, and Lemlist still do that part; the tools below are the monitoring and infrastructure layer that sits next to your sender.
That distinction matters for pricing math. If you already pay $97/month for a sending tool and it lands you in spam anyway, a $25 to $80/month placement monitor is cheap insurance. If you’re sending under a few thousand cold emails a month, you can probably start with free Postmaster Tools and a warmup you run manually.
Quick comparison: pricing at a glance
| MailReach | Folderly | Mailgun (integrated) | ||
|---|---|---|---|---|
| Entry price | about $25/mo per inbox | about $200+/mo | free tier / paid from about $55/mo | included in send platform pricing |
| Warmup | yes, core feature | yes | yes, add-on | not core |
| Inbox placement testing | continuous monitoring | continuous + AI fixes | on-demand seed tests | via deliverability dashboard |
| Best for | agencies warming many inboxes | sales teams at scale | one-off deep tests | teams already on a send platform |
A couple of pricing caveats before you take those numbers literally: Folderly prices per mailbox and the total scales fast if you’re monitoring a dozen senders, and several of these vendors change plan structure a couple of times a year. Treat these as the right magnitude and confirm on the vendor’s site before you buy. GlockApps also runs a useful free seed test if you want to try the concept without paying.
MailReach: the warmup specialist
MailReach built its business on one thing, warming sending reputations for new domains and mailboxes, and it shows. You connect mailboxes, it starts sending simulated exchanges with other network inboxes, and you watch sender score climb over two to four weeks. That’s the standard warmup timeline vendors quote; my own experience warming domains for side projects matches it, roughly three weeks before volume ramps feel safe.
It also does continuous placement monitoring, so it’s a reasonable standalone choice if your sending tool has no warmup of its own. The pricing model is per inbox, which is the cleanest way to think about it: light setup, one or two inboxes, low cost. Agency-scale setups with 20 mailboxes are where the bill starts looking like a second SaaS subscription.
- Per-inbox pricing, starting around $25/month
- Auto warmup with gradual volume ramp
- Spam-assassin style scoring plus placement checks
- Works alongside any sending tool
Folderly: the corporate-grade fix-it tool
Folderly is the most expensive option here and the most opinionated. It doesn’t just show you placement stats, it diagnoses them: it will flag issues with your SPF, DKIM, and DMARC records, content triggers, and sending patterns, with AI-generated recommendations for what to change. Sales teams at companies where dozens of reps send cold email tend to be the actual buyers, and the pricing reflects that, plans generally start in the low hundreds per month.
The honest tradeoff: for a solo founder or a small team, Folderly is probably more tool than you need, and you’d feel the price every month. Where it earns its keep is when multiple reps, multiple domains, and a real pipeline depend on inbox placement, and when nobody on the team knows what DMARC alignment is. It’s also built to integrate its monitoring directly into some ESPs, which cuts the busywork.
- Per-mailbox pricing, roughly $200/month and up depending on scale
- Deep DNS/email-auth diagnostics with fix suggestions
- Ongoing placement monitoring, not just on-demand tests
- Better fit for sales teams than solo senders
GlockApps: the deep-test specialist
GlockApps is the oldest name in this space and works differently: instead of monitoring everything continuously, you run a seed test, sending your campaign draft to a grid of seed accounts across Gmail, Outlook, Yahoo, and corporate providers, and get a per-provider placement report. It’s the equivalent of bringing your car in for an inspection rather than installing a dashboard cam.
Two reasons it still earns a spot on any shortlist in 2026. First, the free tier gives you a real seed test, enough to know whether you have a problem at all. Second, per-test pricing means you can spend $30 checking a big campaign before it launches, rather than paying monthly forever. If your sending volume is modest and episodic (a launch, a reactivation push), pay-per-test is genuinely the cheaper way to buy confidence.
- Free seed test to start, paid plans from about $55/month
- Detailed per-provider placement breakdowns
- DMARC monitoring and analytics in paid tiers
- Best for episodic checks more than always-on monitoring
When you don’t need a paid tool (yet)
Real talk from running my own email setup: if you send fewer than a few thousand cold emails a month, you can get a lot of the value here for free. Google Postmaster Tools shows domain reputation and spam rate for Gmail recipients, Microsoft has its equivalent SNDS, and MXToolbox will watch your DNS and blacklists at no cost. I’d add one honest disclaimer: seed-test panels are small samples and every vendor’s numbers drift from reality a little, so treat any placement percentage as a directional signal, not gospel.
Paid tools start paying for themselves when you’re spending real money on cold outreach infrastructure (multiple domains, sending tools, a rep or two) and a spam-folder problem costs you deals, not just vanity. At that point, $25 to $80/month to catch a placement drop before a campaign launch is a bargain compared to a week of sends that nobody saw.
Which one should you pick?
- Warming a fresh domain now: MailReach. Warmup is the product, pricing scales down to one inbox, and it pairs with whatever sending tool you already use.
- Team of reps, multiple domains, budget approves invoices: Folderly. The diagnostic depth is worth the premium at that scale.
- Occasional big sends, want to check before launching: GlockApps. Pay per test, start free.
- Tiny budget or tiny volume: Free Postmaster Tools plus honest sending habits. Come back to paid tools when volume justifies it.
A quick word on the decision process itself, since pricing pages can make everything look interchangeable. Start by writing down your actual send volume and how many mailboxes you run, because that single line decides most of this. One mailbox and a few hundred emails a week points you at free tooling or the cheapest MailReach tier. Five mailboxes and a couple thousand sends a week puts you in MailReach or GlockApps territory, where per-inbox and per-test pricing both behave reasonably. A whole sales team with pooled domains is where Folderly’s flat-ish team pricing starts making sense despite the sticker shock. People often buy the enterprise option first because it feels serious, then spend a quarter using a tenth of the features. Resist that. You can always upgrade, and the money you don’t spend this quarter buys a better sending domain or a second mailbox, which usually moves deliverability more than a fancier dashboard.
What the pricing actually gets you
It’s worth being concrete about what you’re buying at each price point, because “monitoring” covers a lot of ground. At the low end, around $25 a month, you’re mostly paying for warmup automation and a weekly placement snapshot. That snapshot is genuinely useful: if you watch it for a month you learn whether your domain reputation is stable or drifting, and drifting is what kills campaigns slowly. At the middle tier, roughly $50 to $100 a month, you add continuous monitoring with alerts, so you find out about a spam-folder slide the same day instead of at the end of the month. And at the high end, past $150 a month, you’re buying diagnosis. Not just “you’re landing in spam” but “your DMARC record is misaligned and your emails contain three phrases that spam filters weight heavily.” That last tier only pays off if someone on your team will actually read the reports and act on them. A diagnostic nobody reads is a subscription nobody needed, which is the most expensive kind.
Key takeaways
- Deliverability tools don’t send your email, they protect the money you already spend sending it.
- Gmail and Outlook’s tightening bulk-sender rules are the reason this category keeps growing in 2026.
- MailReach (about $25/mo/inbox) is the warmup pick, Folderly ($200+/mo) the enterprise diagnostic, GlockApps (free tier, from about $55/mo) the pay-per-test option.
- Under a few thousand sends a month? Free Postmaster Tools coverage is probably enough.
- Seed-test numbers are directional, not exact. Watch trends over time, not single test scores.
One last practical tip regardless of tool: nothing beats a slow warm start. Register the domain, set up authentication records properly, send a few dozen emails a day for two weeks, then scale. Every tool above works better when the fundamentals underneath it aren’t broken.