# Warmup Inbox

> Warmup Inbox is an email warm-up service, operated within the itrinity SaaS portfolio, that connects sending accounts to a network of 30,000+ real inboxes which open, reply to, and rescue warm-up emails from spam, priced per inbox across three tiers that scale daily volume to 1,000 emails and add blacklist monitoring across 100+ lists, reputation checks, and warm-up customization.

- Category: Email Deliverability & Warming (https://saastracker.org/categories/email-deliverability)
- Website: https://www.warmupinbox.com
- Starting price: $15/inbox/mo (Basic, billed annually at $180/yr)
- Free plan: No
- Free trial: 7 days, full access to the chosen plan, no credit card required up front
- Founded: 2020, HQ: Bratislava, Slovakia (operated by CyberPanda s.r.o., part of the itrinity portfolio), Ownership: Owned by itrinity (acquired November 2021)
- Profile last reviewed: 2026-08-22
- Canonical profile: https://saastracker.org/products/warmup-inbox

## Overview

Warmup Inbox is one of the longer-running names in the warming-network wing of the deliverability category. Built in 2020 by Mike Benson and acquired in November 2021 by itrinity, the bootstrapped SaaS group behind Mangools and UptimeRobot, it runs the standard reputation loop: your mailbox exchanges email with a claimed network of 30,000+ real human inboxes across 25+ providers, and those counterparties open, reply, mark messages important, and pull them out of spam, teaching Gmail and Outlook that you belong in the inbox. The company claims the network moves around 6 million warm-up emails a day.

Its structure is conventionally per-inbox, but the tiers buy meaningfully different capability rather than just quantity. Basic at $15 per inbox per month (annual) runs 75 warm-up messages a day; Pro at $49 raises that to 250 and unlocks the customization layer (custom templates, topic and language selection, ESP-specific warm-up, scheduling); Max at $79 pushes to 1,000 messages a day per inbox with premium support and unlimited API access. That 1,000-a-day ceiling is unusually high for the category and is aimed at senders warming infrastructure, not just personal mailboxes.

Around the warmer sit real monitoring features: blacklist watching across 100+ lists with help getting delisted, DNS and reputation checks (SPF, DKIM, spam and bounce rates), and placement dashboards. Warmup Inbox publishes aggressive performance claims (98 percent primary inbox placement versus an 83 percent competitor average, 90 percent primary by day 14) that, like all vendor benchmarks in this category, are self-reported and unaudited. Agency features (multi-client workspaces, white-label reports, volume discounts past 15 and 50 inboxes) round out a product that competes squarely with MailReach, Warmy, Warmbox, and Mailivery.

## How it works

1. You connect each inbox via OAuth for Google Workspace and Microsoft 365 or via SMTP/IMAP for other providers, including Zoho, ProtonMail, Fastmail, iCloud, and sending infrastructure like AWS SES and Mailgun. Each connected inbox is a billable unit with its own warming configuration.

2. The service then exchanges email between your inbox and its network of real inboxes: messages get opened, replied to, marked important, and moved out of spam or Promotions when filters misfile them. Daily volume ramps gradually from a low starting point toward your tier's ceiling (75, 250, or 1,000 messages a day) with reply rates up to 25, 45, or 50 percent by tier.

3. On Pro and Max, the customization layer shapes what that traffic looks like: your own templates, chosen conversation topics, warm-up in specific languages for non-English senders, ESP-specific warming patterns, and scheduled sending windows. AI-generated content varies the text of network conversations on all tiers.

4. Meanwhile the monitoring side watches your domains and IPs against 100+ blacklists daily with assistance on delisting, checks DNS and authentication records, and tracks inbox placement, spam rate, and bounce rate on dashboards per inbox. An API (included on all tiers, unlimited on Max) lets agencies and platforms automate inbox management and reporting.

## Best for

Outbound teams and agencies that want per-inbox warming with high daily-volume headroom, real blacklist monitoring with delisting help, and warm-up customization (templates, topics, languages, ESP-specific patterns) for senders that need warming traffic to resemble their real mail.

## Not the right fit for

- Teams with many mailboxes and modest per-mailbox volume; per-inbox billing at $15 to $79 each compounds fast, and Mailivery's unlimited-mailbox shared pool will usually be cheaper past a handful of inboxes.
- Buyers who need deep placement diagnostics; there is no seed-panel testing across providers or DMARC analytics here, so measurement-heavy teams still pair it with a GlockApps-class tool.
- Teams already paying for a sequencer with bundled warming; Instantly and Smartlead include warm-up with the campaign engine at no extra line item.
- Anyone who buys on published benchmarks; the 98 percent placement and day-14 claims are vendor-reported marketing figures, not audited results, and should be treated accordingly.

## Features

### Warming network

The engagement loop against what the company positions as real human inboxes at scale.

- **30,000+ real inbox network**: Warm-up counterparties are real inboxes across 25+ providers rather than synthetic accounts, per the company, with a claimed 6 million warm-up emails moving daily.
- **Positive engagement actions**: Network inboxes open, reply, and mark warm-up messages as important, generating the reputation signals providers score senders on.
- **Spam and category rescue**: Messages landing in spam or the wrong tab are moved to the primary inbox, the direct filter-retraining signal warming depends on.
- **Gradual volume ramping**: Daily send volume rises on a controlled curve toward the tier ceiling so a new domain's pattern stays plausible to providers.
- **AI-generated conversation content**: Network conversations use AI-generated, varied text to avoid the repeated-template fingerprint filters can learn to catch.

### Warm-up customization (Pro and Max)

The layer that makes warming traffic resemble your real sending, a genuine differentiator versus budget warmers.

- **Custom warm-up templates**: Supply your own message templates so warming conversations carry your language and structure rather than generic filler.
- **Topic selection**: Choose the subject matter of warm-up conversations to align with your industry and real campaign content.
- **Language warm-up**: Warm in specific languages, relevant for non-English senders whose real mail would otherwise look nothing like their warming traffic.
- **ESP-specific warm-up**: Warming patterns adjusted for the sending platform behind the inbox, tuned to how different infrastructures deliver.
- **Scheduled warm-up and custom settings**: Sending windows, pacing, and behavior settings put the daily pattern under user control on Pro and above.
- **Template statistics**: Per-template performance reporting shows which warming content is engaging best inside the network.

### Reputation monitoring

The watchdog features that separate this from bare-bones warmers.

- **Blacklist monitoring across 100+ lists**: Daily checks of domains and IPs against more than 100 blocklists, with support for getting delisted when a listing appears.
- **DNS and authentication checks**: SPF, DKIM, and DNS configuration checks catch the authentication failures that no amount of warming can compensate for.
- **Deliverability dashboards**: Real-time tracking of inbox placement of warm-up mail, spam rate, and bounce rate per connected inbox.
- **Email reputation checks**: A consolidated health read per inbox combining placement trends, list status, and configuration checks.
- **Technical setup checks (Max)**: Deeper infrastructure review of a sender's technical configuration is included at the top tier.

### Provider coverage

Wide connection support across consumer, business, and infrastructure senders.

- **Google and Microsoft OAuth**: Native connections for Gmail, Google Workspace, Outlook, and Microsoft 365.
- **Alternative providers**: Yahoo, Zoho, ProtonMail, Fastmail, and iCloud are supported, useful for teams diversifying off the big two providers.
- **Sending infrastructure over SMTP**: AWS SES, Mailgun, and any SMTP-compatible sender can be warmed, extending the tool to transactional and marketing infrastructure.

### Teams, agencies, and platform

The operational layer for running warming as a service or at scale.

- **Developers API on all tiers**: Programmatic inbox management and reporting from the Basic tier up, with unlimited API usage on Max, a rarity among warming tools.
- **Agency plans and volume discounts**: Custom plans start at 15 inboxes with deeper discounts past 50, aimed at agencies warming client rosters.
- **Multi-client workspaces and white-label reports**: Client separation and unbranded reporting let agencies resell warming under their own name with consolidated billing.
- **Outreach sequences**: A lightweight sequence feature is included on all tiers, though it is a convenience next to a dedicated sequencer, not a replacement.

## Use cases

- **Cold-email operator warming sending infrastructure**: A high-volume sender needs mailboxes warmed at hundreds of messages a day each ahead of an aggressive quarter, beyond the 50-to-250 ceilings of most warmers. Outcome: Max-tier inboxes ramp toward 1,000 warm-up messages a day with a 50 percent reply rate, and unlimited API access wires provisioning into the operator's own tooling.
- **Non-English outbound team in a regulated market**: A German-language sales team's warming traffic in generic English looks nothing like its real correspondence, blunting the reputation signal. Outcome: Language warm-up and custom templates on Pro make the warming conversations match the team's real sending in language and topic, tightening the fit between warmed and actual reputation.
- **Agency reselling deliverability management**: A lead-gen agency wants warming, monitoring, and client reporting under its own brand across 30 client inboxes. Outcome: An agency plan with volume discounts, multi-client workspaces, and white-label reports packages the whole service, and blacklist monitoring with delisting help covers the remediation clients actually call about.
- **Startup recovering from a blacklisting**: A launch announcement sent to a stale list got the domain listed on several blocklists and campaign placement collapsed. Outcome: Daily monitoring across 100+ lists confirms which listings matter, delisting assistance works them down, and a fresh warming ramp rebuilds engagement history while the team fixes list hygiene.

## Pricing

Per-inbox monthly subscription in three tiers that scale daily warm-up volume, reply rate, and feature depth; annual billing saves 20 percent, and custom agency plans start at 15 inboxes.

- **Basic**: $15 per inbox per month, billed annually ($180/yr per inbox); monthly billing runs about 20 percent higher. 75 warm-up messages/day, reply rate up to 25%; 30K+ inbox network, spam and category monitoring; Email reputation checks, dashboards, AI content; Developers API and chat support.
- **Pro**: $49 per inbox per month, billed annually ($588/yr per inbox). 250 warm-up messages/day, reply rate up to 45%; Custom templates, topics, and language warm-up; ESP-specific and scheduled warm-up, template statistics; Priority support. Marketed as the best-value tier; the customization layer lives here.
- **Max**: $79 per inbox per month, billed annually ($948/yr per inbox). 1,000 warm-up messages/day, reply rate up to 50%; Technical setup checks and premium support; Unlimited developers API, early feature access.
- **Agency / volume**: Custom per month. Custom plans from 15 inboxes, larger discounts past 50; Multi-client workspaces, white-label reports, consolidated billing.

Billing notes:

- Displayed prices are the annual-billing rate with yearly totals of $180, $588, and $948 per inbox; the site advertises 20 percent annual savings, so budget monthly billing accordingly higher.
- Billing is strictly per inbox, so total cost scales linearly with mailbox count; ten Basic inboxes cost $150 a month before any agency discount.
- The tier jump from Basic to Pro more than triples the per-inbox price; it buys volume and the whole customization layer, so senders who just need 75 messages a day should resist the upsell.
- The 7-day trial takes no credit card up front, making evaluation genuinely free, which is friendlier than the card-required trials common in the category.

Value assessment: Warmup Inbox prices capability, not just quantity: $15 buys a competent standard warmer with monitoring, $49 buys the customization that makes warming traffic resemble your real mail, and $79 buys volume headroom (1,000/day) almost nobody else publishes. For one to a few inboxes that ladder is fair, and the blacklist monitoring with delisting help does work competitors charge separately for. The weakness is arithmetic: per-inbox billing compounds, and a 10-mailbox team at Pro pays $490 a month where Mailivery's Business tier covers unlimited mailboxes for $199. Buy Warmup Inbox for depth per inbox; buy elsewhere for breadth of inboxes.

## Strengths

- Highest published per-inbox volume ceiling in its peer group (1,000 warm-up messages a day on Max), suited to warming infrastructure and aggressive senders.
- Blacklist monitoring across 100+ lists with delisting assistance is real remediation tooling, not just an alert feed.
- The Pro customization layer (custom templates, topics, language warm-up, ESP-specific patterns) makes warming traffic resemble actual sending better than generic warmers manage.
- API access on every tier, unlimited on Max, gives agencies and platforms a programmatic surface most competitors reserve for enterprise deals.
- Stable ownership: part of itrinity's bootstrapped portfolio (Mangools, UptimeRobot) since 2021, with less key-person risk than single-founder micro-vendors.
- No-card 7-day trial and strong public review footprint (4.6/5 across G2, Trustpilot, and Capterra on 220+ combined reviews) lower evaluation risk.

## Limitations

- Per-inbox pricing compounds quickly; multi-mailbox teams pay multiples of what shared-pool or unlimited-mailbox competitors charge.
- Headline performance claims (98 percent primary placement, 90 percent by day 14) are self-reported vendor benchmarks with no independent audit.
- No seed-panel placement testing or DMARC analytics; measurement beyond warm-up traffic and list status requires a separate diagnostics tool.
- The bundled outreach-sequences feature is thin next to dedicated sequencers and should not factor into the buying decision.
- The best differentiating features (templates, topics, languages, ESP-specific warming) start at $49 per inbox, a steep step from the $15 entry tier.
- Engagement-network warming remains a provider gray zone; Google and Microsoft periodically tighten enforcement against warming pools, a risk shared across the category.

## Comparisons

- **Warmup Inbox vs Mailivery**: Opposite pricing philosophies: Warmup Inbox meters per inbox and scales depth (volume to 1,000/day, customization, delisting help), while Mailivery sells unlimited mailboxes against a shared daily pool with bundled verification and placement tests. Few inboxes warmed hard favors Warmup Inbox; many inboxes warmed moderately favors Mailivery.
- **Warmup Inbox vs Warmbox**: Both are focused warmers, but Warmup Inbox layers on 100+ list monitoring, delisting support, an API on every tier, and Pro-level customization; Warmbox counters with a lower entry price and bundle-of-inboxes simplicity. Pick Warmbox to warm cheaply; pick Warmup Inbox when monitoring, customization, or per-inbox volume headroom matter.
- **Warmup Inbox vs InboxAlly**: InboxAlly sells controlled engagement from its own seed pool with an emphasis on marketer and newsletter recovery, at noticeably higher entry pricing; Warmup Inbox is the conventional per-inbox warmer with broader self-serve tooling and agency features. Recovery-focused marketers with budget lean InboxAlly; outbound teams and agencies buying standard warming lean Warmup Inbox.
- **Warmup Inbox vs Instantly**: Instantly bundles warm-up free with its sequencer and unlimited-mailbox model, which is hard to beat if you are buying the sending platform anyway. Warmup Inbox is the standalone specialist: deeper warming controls, real blacklist remediation, and no requirement to move your sending stack. Teams committed to Instantly rarely need it; teams on other sequencers or ESPs often do.

## Implementation

- Setup time: Minutes per inbox via OAuth or SMTP; the vendor claims 90 percent primary placement by day 14, but 2 to 4 weeks remains the realistic window before a new domain carries campaign volume.
- Learning curve: Low on Basic, where defaults do the work; moderate on Pro and Max, where templates, topics, ESP-specific settings, and scheduling reward deliberate configuration.
- Onboarding: Self-serve with chat support; priority and premium support attach to Pro and Max, and technical setup checks on Max add a guided infrastructure review.
- Migration: No lock-in beyond history: disconnect inboxes and the service ends, losing warming and monitoring trends. Workspace admins may need to approve OAuth scopes or enable SMTP/IMAP.

## Platform, API & security

- Platforms: Web app, Developers API (all tiers, unlimited on Max)
- API: A developers API for inbox management and reporting is included on every tier, with unlimited usage at the Max tier; documented limits below Max are not published in detail.
- Compliance: GDPR-aligned processes with a published data processing agreement
- Data residency: Operated by CyberPanda s.r.o., Bratislava, Slovakia (EU); specific residency guarantees are not published.
- SSO: Not advertised.
- Security notes: Warming requires standing OAuth or SMTP/IMAP access to connected inboxes. A public DPA is available; no SOC 2 or equivalent attestation is referenced as of this review.

## Support

- Channels: Chat support (all tiers), Priority support (Pro), Premium support (Max)
- Documentation: Help documentation plus a content library on warm-up practice and deliverability.
- Community: No dedicated user community; the affiliate program is the main external ecosystem.

## Company

- Founded: 2020
- Founders: Mike Benson
- Headquarters: Bratislava, Slovakia (operated by CyberPanda s.r.o., part of the itrinity portfolio)
- Ownership: Owned by itrinity (acquired November 2021)
- Employees: Not disclosed (small team within itrinity's bootstrapped portfolio)
- Funding: Bootstrapped, then acquired by itrinity, itself a bootstrapped SaaS group (Mangools, UptimeRobot); terms undisclosed.

Timeline:

- 2020: Mike Benson builds and launches Warmup Inbox as a standalone email warm-up service.
- 2021: itrinity, the bootstrapped group behind Mangools and UptimeRobot, acquires Warmup Inbox in November; terms undisclosed.
- 2023: Monitoring expands into a real remediation layer: blacklist watching across 100+ lists with delisting assistance alongside DNS and reputation checks.
- 2025: The Basic/Pro/Max structure matures, concentrating customization (templates, topics, languages, ESP-specific warming) in Pro and pushing Max volume to 1,000 messages a day per inbox.
- 2026: As of this review the network claims 30,000+ real inboxes across 25+ providers moving roughly 6 million warm-up emails daily, with agency plans from 15 inboxes.

## Integrations

Gmail / Google Workspace (OAuth), Outlook / Microsoft 365 (OAuth), Yahoo Mail, Zoho Mail, ProtonMail, Fastmail, iCloud Mail, AWS SES (SMTP), Mailgun (SMTP), Any SMTP-compatible provider, Developers API

## FAQ

### What does Warmup Inbox do?

It warms email accounts by exchanging messages with a network of 30,000+ real inboxes that open, reply, mark as important, and rescue your mail from spam, building sender reputation with providers. Around that it monitors 100+ blacklists with delisting help, checks DNS and authentication, and tracks placement, spam, and bounce metrics per inbox.

### How much does Warmup Inbox cost?

Three per-inbox tiers: Basic at $15/inbox/month, Pro at $49, and Max at $79 on annual billing (totals of $180, $588, and $948 per inbox per year), with the site citing 20 percent annual savings versus monthly billing. Agency plans with volume discounts start at 15 inboxes.

### What do the higher tiers actually add?

Volume and control. Basic runs 75 warm-up messages a day with standard warming; Pro raises volume to 250 and adds custom templates, topic and language selection, ESP-specific and scheduled warm-up; Max pushes to 1,000 messages a day with technical setup checks, premium support, and unlimited API use.

### Is there a free trial?

Yes, 7 days of full access to whichever plan you choose, with no credit card required up front, so the trial carries no cancellation risk.

### How fast does Warmup Inbox work?

The vendor claims 90 percent primary inbox placement by day 14 and 98 percent at steady state, but those are self-reported figures. Realistically, plan the category-standard 2 to 4 weeks before a new domain carries meaningful campaign volume, and keep maintenance warming running afterward.

### Does Warmup Inbox monitor blacklists?

Yes, domains and IPs are checked daily against more than 100 blocklists, and the service assists with delisting when a listing appears, which is remediation work many warming competitors leave entirely to the customer.

### Which providers can I connect?

Gmail and Google Workspace, Outlook and Microsoft 365, Yahoo, Zoho, ProtonMail, Fastmail, and iCloud, plus sending infrastructure like AWS SES and Mailgun or any SMTP-compatible system.

### Does Warmup Inbox have an API?

Yes, a developers API is included on every tier for managing inboxes and pulling reporting, with unlimited usage on Max. That makes it one of the few warmers exposing programmatic access below enterprise pricing.

### Does it test where my real campaigns land?

Not with a seed panel. Dashboards track placement of warm-up traffic plus spam and bounce rates, but there is no cross-provider seed testing of your actual campaign content and no DMARC analytics; pair it with a diagnostics tool like GlockApps or MailerCheck if you need proof of campaign placement.

### Who owns Warmup Inbox?

It was built in 2020 by Mike Benson and acquired in November 2021 by itrinity, the bootstrapped SaaS portfolio behind Mangools and UptimeRobot. Day-to-day operations run through CyberPanda s.r.o. in Bratislava, Slovakia.

## Editorial verdict

Warmup Inbox is the depth-per-inbox pick among warming networks. The Pro customization layer and Max's 1,000-a-day ceiling solve real problems generic warmers cannot (non-English senders, ESP-specific patterns, infrastructure warming), and blacklist monitoring with delisting help plus an API on every tier make it operationally serious for a tool starting at $15. Its structural weakness is the meter: per-inbox billing turns a large mailbox roster into a large invoice, exactly the scenario shared-pool and bundled-warming competitors are built to win. Choose Warmup Inbox to warm a limited set of inboxes hard and watch their reputation properly; choose Mailivery or a sequencer's built-in warming when mailbox count, not warming depth, is the problem.

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Source: SaaSTracker (https://saastracker.org), an independent editorial project. This profile is compiled from public information, carries no peer reviews or paid placement, and was last reviewed 2026-08-22. Awards are judged on published criteria: https://saastracker.org/methodology