Very few inbox providers offer all the different types of inboxes. InboxKit is special. It provides Google, Microsoft, and Azure inboxes and runs warmup. Their setup is the most complete I’ve seen among cold email inbox providers. However, there are a couple of loopholes that I will explain in this InboxKit review.
The information mentioned in this review is sourced from G2 + Trustpilot + user insights on Reddit. I’ve read through the documents on InboxKit and consolidated everything into this review.
Key Takeaways
What does every cold emailer expect from an inbox provider? Different types of inboxes? Built-in warmup? InboxKit fills most of the checkboxes. It provides Google, Microsoft, and Azure inboxes, warmup your inboxes, and monitor inbox reputation. The starting plan is $39/month with 10 inboxes.
- Inbox: Google, Microsoft, and Azure
- USP: API available on every plan
- Deliverability: Claims 95% inbox placement (no methodology)
- Risk: Paid add-ons - Warmup at $3/inbox, and InfraGuard is free for the 1st month
- Starting Plan: $39/month for 10 inboxes
- Support: Dedicated reps, founder-level involvement, and a Slack channel on higher tiers
About InboxKit
InboxKit is a cold email inbox service provider that resells Google, Microsoft, and Azure inboxes sourced from an official reseller. Inboxkit guarantees “95% inbox placement” but offers no methodology to test it. It offers built-in warm-up, priced at $3/inbox, and Infraguard for real-time monitoring & alerts. If you want to automate your campaigns, you can refer to the InboxKit API docs for full access.
How InboxKit Works
InboxKit Features
Multiple Inbox Provider
InboxKit provides official Google, Microsoft, and Azure inboxes. These are Indian inboxes sourced from official Indian resellers.
InfraGuard Deliverability Monitoring
You can monitor your domain performance using InfraGuard. It tracks the domain’s reply rate, inbox placement, and warmup reputation. If a domain is flagged, the user is alerted. It is billed at $3/domain.
Full REST API with Every Plan
InboxKit offers a full REST API on every plan. An agency can script bulk integration, pull inbox analytics, and feed updates on its own tech stack.
Isolated Warmup
With InboxKit isolated warmup, you can build a sender inbox reputation. It tracks inbox and spam rate and manages the reputation.
Pros
Quick Setup
InboxKit sets up your inboxes very quickly. It auto-configures SPF, DKIM, and DMARC of +200 inboxes via Cloudflare in about ten minutes.
Three Inbox Types From One Vendor
Unlike most resellers, InboxKit provides official Google, Microsoft, and Azure inboxes. The inboxes come through the Indian reseller channel: real Google and Microsoft accounts, but India-origin rather than Google’s direct channel. You can get 10 Google/Microsoft inboxes for $39/month.
Developer-Grade Control with Full API
InboxKit offers the full REST API on each plan. It is very useful in setting up, managing, and monitoring your campaigns in bulk. You can add inboxes, track their performance, and automate the reporting. All you have to do is create a script, and it will perform end-to-end operations within minutes.
Built-in Warmup
Inboxkit offers in-built warmup at an additional cost. However, the warmup lacks ESP % (What % of emails go to Google vs Outlook) and you cannot send emails in different languages.
Cons
Warmup and Monitoring Cost Extra
Warmup is currently billed at $3/inbox per month. If you buy the monthly ‘Professional’ plan, which includes 10 inboxes, you’re paying $39 + $30 = $69 for the first month. In the second month, the Infraguard cost, i.e. $3/domain is added on top of additional cost. Total cost incurred in the second month – $39 + $30 + $9 = $78 (suppose you host 10 inboxes on 3 domains).
“95%” Inbox-Placement Claim
InboxKit markets “95% inbox placement” across its site, but it does not provide the methodology to substantiate the claim. Achieving “95% inbox placement guaranteed” is tough, even with “official” inboxes.
Indian Origin Accounts
All inboxes come through the Indian reseller channel rather than Google’s direct channel, and InboxKit does not publish the source.
The Credibility of Warmup
Their “isolated” warmup pool doesn’t have any methodology. Although it is still better than the sequencer warmup, the process is not made public. For example, the topic or language is not defined. If you’re warming an inbox for D2C healthcare, it is important to use healthcare-specific terminology in the copy.
InboxKit Pricing
InboxKit offers three plans, billed monthly, quarterly, and annually.
| Plan | Monthly | Quarterly | Annual | Inbox Slots | Additional Inbox (M/Q/A) |
|---|---|---|---|---|---|
| Professional | $39 | $35 | $31 | 10 | $3.50 / $3.40 / $3.10 |
| Agency (Most Popular) | $99 | $90 | $81 | 30 | $3.25 / $3.00 / $2.70 |
| Enterprise | $299 | $290 | $250 | 100 | $2.99 / $2.90 / $2.50 |
Professional10
- Monthly
- $39
- Quarterly
- $35
- Annual
- $31
- Inbox Slots
- 10
- Additional Inbox (M/Q/A)
- $3.50 / $3.40 / $3.10
Agency (Most Popular)30
- Monthly
- $99
- Quarterly
- $90
- Annual
- $81
- Inbox Slots
- 30
- Additional Inbox (M/Q/A)
- $3.25 / $3.00 / $2.70
Enterprise100
- Monthly
- $299
- Quarterly
- $290
- Annual
- $250
- Inbox Slots
- 100
- Additional Inbox (M/Q/A)
- $2.99 / $2.90 / $2.50
Available as paid add-ons –
- Email Warmup = $3/inbox per month
- InfraGuard – Billed from the 2nd month i.e. $3/domain per month
- Official admin panel (1 per domain) with 2FA
- 24+ platform integrations
- Unlimited team members & workspaces
- Full API access with webhooks
- Email & chat support
InboxKit vs Aerosend
InboxKit and Aerosend both sell inboxes with warmup and monitoring attached, but on different terms.
The differences: InboxKit is a reseller, charges extra for warmup and monitoring, and publishes no methodology behind its deliverability claim. You can buy Google, Microsoft, or Azure inboxes and pay extra to warmup the inboxes.
Aerosend builds a dedicated server with aged IPs for your domains. It includes a complimentary premium warmup.
InboxKit guarantees 95% inbox placement. Aerosend isolates every 10 domains on a dedicated server and runs a premium warmup to ensure that your deliverability rate is high.
InboxKit charges $3/domain to monitor your deliverability. Aerosend includes biweekly inbox placement tests and applies a 6-metric burn-detection algorithm to flag and replace affected domains.
Here is how each cold email inbox service provider compares:
| Compare | InboxKit | AerosendPrivate infrastructure |
|---|---|---|
| Inbox Available | GoogleMicrosoftAzureSourced from official Indian resellers | Private infrastructureBuilt for cold email, so no Google or Outlook bans |
| Warmup | ~Paid add-onBuilt-in warmup at $3/inbox per month; methodology unpublished | ✓Included, ongoingComplimentary premium warmup, matched to who you email |
| Monitoring | ~Paid add-onInfraGuard at $3/domain from month two, alerts on flags | ✓Six metricsEvery domain scored daily and surfaced to you |
| Deliverability | ~Claimed, unverifiedMarkets 95% inbox placement with no methodology; self-managed | ✓Our responsibilityBiweekly inbox placement tests, included |
| Domain Burn Alerts | ~Paid add-onBounce and health scoring via InfraGuard | ✓IncludedBurnt domains flagged within 5 minutes, replaced in one click |
| Pricing | $39 per 10 inboxesProfessional monthly, about $3.90/inbox; warmup $3/inbox extra | $4 / inbox$2 per inbox past 150 · 30 inboxes = $120/mo |
| Ready To Test? | Visit InboxKit Website ↗ | Try Aerosend For Free |
Price/Mailbox Breakdown (~5,000 emails/day)
| Requirements | InboxKit | Aerosend |
|---|---|---|
| Inboxes needed | ~250 (at the 20/day safe band) | 200 |
| Send rate per Inbox | 20/day (safe band; InboxKit targets 40) | 20-25/day |
| Plan | Enterprise annual (100 slots) + 25 additional inbox + warmup | Starter banded into Growth |
| Per-inbox rate | $2.50/inbox + $3/inbox warmup = $5.50 effective | $3.50 (blended) |
| Monthly total | ~$687/mo (125 × $5.50) | ~$700 |
| Service model | Self-managed | Managed |
InboxKit Support
Support is available via both chat and email. You can email InboxKit support at support {at} inboxkit {dot} com.
The dedicated Slack channel has been added to the Enterprise plan.
I like the customer support the most. Their support is very good and involved, with a dedicated representative who can even do biweekly calls if necessary. It’s a same-day experience with good deliverability. Everything can be done from start to finish in a few hours, unlike other vendors that might take one to two weeks.
Walter W., G2
The Verdict
If you want to run a bulk cold email campaign and require a multi-inbox setup that monitors your deliverability, you can opt for InboxKit. It sets up your inboxes, runs warmup, and monitors your domains.
On top of this, full API access on every plan + top-notch support earns it a respectable 4 out of 5.
