# coldemailinboxes.io > Pre-configured Microsoft 365 cold email inbox infrastructure for agencies and B2B outbound teams. ## About coldemailinboxes.io provides ready-to-deploy Microsoft 365 inbox infrastructure for outbound email campaigns. The service focuses on inbox provisioning, domain setup, email authentication, and handoff rather than sending software. ## Offer - $30 per order for 100 Microsoft 365 inboxes on one domain. - Each inbox is configured for 3 emails per day, providing 300 emails per order per day. - SPF, DKIM, and DMARC configuration is handled as part of setup. - Customers can bring their own domain at no extra charge. - Domain purchase is available for $12 per domain. - Typical deployment timing is 48-72 hours, depending on volume and DNS/API setup. - Compatible with common outbound sequencing platforms, including Smartlead, Instantly, Lemlist, Woodpecker, Reply.io, and Apollo. ## Public pages - [Homepage](https://coldemailinboxes.io/): Microsoft 365 cold email inbox offer, calculator, pricing, integrations, and FAQ. - [Free DNS Records Checker](https://coldemailinboxes.io/tools/dns-records-checker): Checks SPF, DKIM, DMARC and MX for a domain in one pass, with per-record verdicts. Also accepts a bulk list of up to 25 domains and exports the results as CSV. DKIM is found by probing 57 common provider selectors; custom selectors can be supplied. - [SPF Checker](https://coldemailinboxes.io/tools/spf-checker): Free SPF record lookup. Parses the record, counts the RFC 7208 ten-lookup budget, flags a missing "all" mechanism or multiple records, and reports whether Microsoft 365 is authorized. - [DMARC Checker](https://coldemailinboxes.io/tools/dmarc-checker): Free DMARC policy lookup at _dmarc.. Reports the policy tag, subdomain policy, pct and rua/ruf reporting addresses. - [DNS Checker](https://coldemailinboxes.io/tools/dns-checker): Free MX, TXT, A, AAAA and NS record lookup, with MX sorted by priority. - [Email Blacklist Checker](https://coldemailinboxes.io/tools/blacklist-checker): Free DNSBL lookup for a domain or IPv4 address across Spamhaus ZEN, SpamCop, Barracuda, SORBS and PSBL. All four tools perform live DNS queries and are free to use with no account. ## Guides - [Cold email inboxes: what they are and how to buy them](https://coldemailinboxes.io/cold-email-inboxes): Buying guide covering what a cold email inbox is, how to size an inbox pool from a target daily volume, Microsoft 365 against Google Workspace for outbound, what providers charge per inbox, and what to check before buying. - [Deliverability best practices](https://coldemailinboxes.io/deliverability): Reference guide to cold email sending practice - safe volume per inbox, warm-to-cold ratio, warmup, copy variation, spintax, engagement, and a method for diagnosing whether a reply-rate drop is caused by the domain, the copy, the tenant or the infrastructure. - [Blog index](https://coldemailinboxes.io/blog): All guides on cold email infrastructure. - [Microsoft 365 vs Google Workspace for cold email](https://coldemailinboxes.io/blog/microsoft-365-vs-google-workspace-cold-email): Platform comparison covering inbox placement when recipients are on Outlook, actual sending limits including the Microsoft Tenant External Recipient Rate Limit, alias headroom, bulk provisioning and cost per inbox. - [SPF, DKIM and DMARC for cold email](https://coldemailinboxes.io/blog/spf-dkim-dmarc-cold-email-setup): The exact DNS records for authenticating a cold email sending domain, the SPF ten-lookup limit, DMARC alignment, and the misconfigurations that fail silently. - [How many cold emails per inbox per day](https://coldemailinboxes.io/blog/how-many-cold-emails-per-inbox-per-day): Why three per Microsoft 365 inbox per day is the safe rate, why platform caps are not deliverability guidance, warmup schedules, and how to size an inbox pool from a target volume. - [Cold email domain strategy](https://coldemailinboxes.io/blog/cold-email-domain-strategy): Why cold email needs domains separate from the primary, how to choose and check sending domains, redirects, and per-domain authentication. - [Cold email deliverability checklist](https://coldemailinboxes.io/blog/cold-email-deliverability-checklist): Pre-send checklist covering authentication, domain and inbox setup, warmup, list hygiene, content, sending behaviour and the metrics that signal trouble. ## Key facts - Safe cold email volume on Microsoft 365 is about 3 emails per inbox per day. Google Workspace tolerates more, commonly 25-30 per inbox per day. - Microsoft 365 platform limits are 10,000 recipients per mailbox per day and 30 messages per minute, plus a Tenant External Recipient Rate Limit of roughly 500 x (licences ^ 0.7) + 9,500 external recipients per day across the whole tenant. - Google Workspace limits are 2,000 messages per user per day, 3,000 external recipients per day and 10,000 total recipients per day. - Domain warmup should run at least two weeks before meaningful cold volume, and continue alongside cold sending. - A reply-rate drop that follows one domain across many campaigns indicates a domain problem; one that follows one campaign across many domains indicates a copy or offer problem. ## Policies and support - [About](https://coldemailinboxes.io/about): What the service provisions and how deployment works. - [Support](https://coldemailinboxes.io/support): Troubleshooting for authentication, DNS propagation, warmup, sequencer connection and blacklist removal. - [Terms of Service](https://coldemailinboxes.io/terms): Fees, delivery, ownership of domains and inboxes, refunds. - [Privacy Policy](https://coldemailinboxes.io/privacy): What data is collected, why, and how long it is kept. - [Acceptable Use Policy](https://coldemailinboxes.io/acceptable-use): Prohibited sending practices and CAN-SPAM, GDPR and CASL obligations. ## Contact - Website: https://coldemailinboxes.io/ - Email: info@coldemailinboxes.io