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InboxKit Pricing: Complete Breakdown and Calculator (2026)
By Mohit MimaniPublished on: Mar 30, 2026 · 10 min read · Last reviewed: Mar 2026
TL;DR
InboxKit offers tiered plans starting at $39/mo for 10 mailboxes, with per-mailbox rates from $2.99 on Enterprise. Warmup available as a $3/mailbox/mo add-on, and InfraGuard monitoring included. Here is the complete cost breakdown.
InboxKit Pricing Overview
InboxKit uses a tiered subscription model with three plans designed for different scales:
| Plan | Monthly Price | Included Mailbox Slots | Additional Mailbox Cost |
|---|---|---|---|
| Professional | $39/mo | 10 mailboxes | $3.50/mailbox |
| Agency | $99/mo | 30 mailboxes | $3.25/mailbox |
| Enterprise | $299/mo | 100 mailboxes | $2.99/mailbox |
Annual billing is cheaper (e.g., Enterprise annual: $250/mo, $2.50/additional mailbox). There are no hidden platform fees beyond the plan price.
This is fundamentally different from competitors like Primeforge ($29/mo platform fee) or Instantly ($30-97/mo platform fee) that charge you before you even create a single mailbox.
Core Pricing Breakdown
Here is the complete pricing table:
| Plan | Monthly Price | Included Mailboxes | Per Additional Mailbox |
|---|---|---|---|
| Professional | $39/mo | 10 slots | $3.50/mailbox |
| Agency | $99/mo | 30 slots | $3.25/mailbox |
| Enterprise | $299/mo | 100 slots | $2.99/mailbox |
| Add-On / Service | Price | Notes |
|---|---|---|
| Warmup | $3.00/mailbox/mo | Isolated warmup network |
| Azure Domain | $30/domain | Up to 100 mailboxes per domain |
| Domain Registration | From $2/year | DNS auto-configured |
| InfraGuard Monitoring | Per-domain pricing | Blacklists, DNS, reputation, auto-pause |
| Inbox Placement Tests | Per-test from wallet | Seed-based testing |
All plans support both Google Workspace (US-IP) and Microsoft 365 mailboxes. Annual billing reduces costs further (e.g., Enterprise annual: $250/mo, $2.50/additional). As shown on the InboxKit pricing page (see screenshot above), everything is transparent. There are no hidden fees beyond the plan price, no overage charges, and no annual lock-in.
Cost Calculator: Common Setups
| Setup | Plan | Mailboxes | Plan + Additional | Warmup ($3/ea) | Monthly Total |
|---|---|---|---|---|---|
| Starter | Professional $39/mo | 10 | $39 (all included) | $30 | $69/mo |
| Growth | Agency $99/mo | 25 | $99 (all included) | $75 | $174/mo |
| Scale | Agency $99/mo | 50 | $99 + 20 extra x $3.25 = $164 | $150 | $314/mo |
| Agency | Enterprise $299/mo | 100 | $299 (all included) | $300 | $599/mo |
| Large | Enterprise $299/mo | 200 | $299 + 100 extra x $2.99 = $598 | $600 | $1,198/mo |
- Enterprise plan: $299/mo (includes 100 mailboxes)
- 100 additional mailboxes: 100 x $2.99 = $299
- Warmup: $3.00 x 200 = $600.00
- Total: $1,198/mo (before domains and InfraGuard)
Both Google Workspace and Microsoft 365 mailboxes count toward plan slots. Domain registration, InfraGuard monitoring, and inbox placement tests are additional costs. DNS automation and 24+ sequencer integrations are included.
InboxKit vs Competitor Pricing
50 Mailbox cost comparison (monthly):
| Provider | Plan / Pricing | 50 Mailbox Total | Notes |
|---|---|---|---|
| InboxKit | Agency $99/mo (30 incl.) + 20 x $3.25 | $164/mo | Google + Microsoft, InfraGuard included |
| ZapMail | Growth $99/mo (30 incl.) + 20 x $3.25 | $164/mo | Google + Microsoft 365, no monitoring, no Azure |
| Maildoso | ~$2.50/mailbox flat | ~$125/mo | Shared infrastructure |
| Primeforge | $3.50-4.50/mailbox | $175-225+ | Varies by plan |
| Instantly | ~$4.00/mailbox + platform | $230-297 | $30-97/mo platform fee |
InboxKit and ZapMail have nearly identical plan structures and pricing. The differentiation is in infrastructure quality, not price.
What is included vs. extra:
| Feature |  InboxKit |  ZapMail |  Primeforge |  Mailforge |
|---|---|---|---|---|
| Microsoft 365 | Yes | Yes | No | No |
| Azure Mailboxes | Yes ($30/tenant, 100 mailboxes) | No | No | No |
| Warmup | $3/mailbox/mo (isolated) | Pre-warmed option ($6-8/mailbox premium) | Warmforge $2/mailbox | Warmforge $2/mailbox |
| Monitoring | InfraGuard (per-domain) | None | Infraforge $1.50/mailbox | Infraforge $1.50/mailbox |
| Inbox Testing | Wallet-based | None | None | None |
| DNS Automation | Included | Semi-automated | Partial | None |
| Integrations | 24+ sequencers | 5 | 4 | 3 |
ROI Analysis
The real question is cost per email delivered to inbox.
- 100 mailboxes sending 40 emails/day = 4,000 emails/day
- 82% inbox rate = 3,280 inbox deliveries/day
- Enterprise plan: $299/mo (100 mailboxes included)
- Monthly warmup cost: $3.00 x 100 = $300
- Total: $599/mo (before InfraGuard)
- Cost per inbox delivery: $599 / (3,280 x 30) = $0.0061
- Same volume: 3,000 inbox deliveries/day
- Monthly cost: ~$500
- Cost per inbox delivery: $500 / (3,000 x 30) = $0.0056
The per-delivery costs are in a similar range. InboxKit's advantage is the isolated warmup quality (which produces higher inbox placement) and InfraGuard monitoring (which catches issues before they tank deliverability). For teams where every percentage point of inbox placement matters, InboxKit's total value proposition is stronger.
Getting Started
- 1Create your account at inboxkit.com
- 2Choose a plan (Professional $39/mo, Agency $99/mo, or Enterprise $299/mo)
- 3Buy domains and create mailboxes within your plan slots
- 4Activate warmup ($3.00/mailbox/mo) and InfraGuard (per-domain pricing)
- 5Start sending after 14-21 days of warmup
No contracts, no hidden fees beyond the plan price. Scale up or down anytime by upgrading plans or adding mailboxes.
Frequently Asked Questions
InboxKit uses tiered subscription plans starting at $39/mo (Professional). The plan price includes your mailbox slots. there are no hidden platform fees on top of the plan price. You only pay for your plan, any additional mailboxes beyond included slots, and optional add-ons like warmup.
The Enterprise plan ($299/mo) includes 100 mailboxes with additional mailboxes at $2.99 each. On annual billing, Enterprise drops to $250/mo with $2.50/additional mailbox. The Professional plan starts at $39/mo for 10 mailboxes.
No. Warmup is a separate add-on at $3.00/mailbox/mo. The plan price covers your mailbox slots. Warmup uses an isolated network for higher quality results compared to shared pools used by competitors.
Google Workspace direct costs $7.20/month per user, and you handle DNS setup, warmup, and monitoring yourself. InboxKit plans start at $39/mo for 10 mailboxes (effectively $3.90/mailbox at the Professional tier, down to $2.99/mailbox on Enterprise), with automated DNS and warmup available at $3/mailbox/mo as an add-on.
Sources & References
- 1
InboxKit Pricing Page(2026)
- 2
InboxKit Pricing Docs(2026)
- 3
Google Workspace Pricing(2026)
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