Mailgun vs Postmark cost

Pricing and selected limits checked 2026-09-21. USD per month before taxes and optional add-ons. These are reproducible calculations from published prices, not sending-speed tests or observed invoices.

The short answer: sending pattern and features change the bill

At 10,000 monthly emails, Mailgun Basic and Postmark Basic both list $15. Mailgun can cost less for a small, evenly spread workload; a one-day burst changes that answer. Postmark’s larger volume choices matter too: choosing the 50k allowance costs less than adding 40k emails to its 10k Basic plan. If replies must flow into your application, Postmark Basic does not include inbound email.

Eight scenarios you can reproduce

Mailgun’s primary pricing card lists Scale at $90 for 100k. A separate official offer advertises $75 for 100k without naming the plan in that table. We do not label $90 its cheapest available offer or assume the $75 offer includes Scale’s features. Verify the selected plan before paying. Foundation and Scale overage schedules vary with sent volume, so this calculator leaves totals beyond their included allowance unknown.

For inbound at 100k, Postmark Pro 50k is $60.50 plus 50 × $1.30 = $125.50. Pro 125k at $126.50 is a simple prepaid alternative, but costs $1 more for that exact month. Without inbound, Basic 125k at $115 is the lower cost choice. Overage calculations round up to complete published billing units; the scenarios above use exact multiples of 1,000, so they do not establish how a vendor rounds a 10,001-email invoice.

A free daily allowance is not a monthly allowance

Mailgun Free allows 100 emails per day. Sending 1,000 messages over ten days with no day above 100 fits that cap; sending all 1,000 on launch day does not. Enter your busiest day below. If it is unknown, we cannot certify free-tier eligibility from a larger monthly total. Postmark Free instead allows 100 emails per month and does not allow overage. A paid plan’s lack of a daily cap is not a guarantee of arbitrary instantaneous throughput.

Choose around the work you need to do

• Debug a receipt weeks later: Postmark lists 45-day full-message/activity retention. Mailgun Free and Basic list one-day event logs; Foundation lists five-day logs and one-day message storage; Scale lists 30-day logs and up to seven-day message retention. Event logs and message content are different records.
• Accept customer replies: Postmark inbound is included on Free, Pro and Platform, but not Basic. Mailgun Free lists one inbound route, Basic five, and Foundation full inbound routing.
• Separate several applications: Postmark Basic lists five sending domains, Pro ten, Platform unlimited. Mailgun Basic lists one domain and Foundation up to 1,000. Check limits against your tenant model.
• Choose data location: Mailgun documents US/EU hosting choices. Confirm the actual region and data requirements for your account; this is not a legal-compliance certification.

Postmark counts sent messages, processed inbound, sandbox traffic and each CC/BCC recipient toward usage. Broadcast messages use separate Broadcast Message Streams; it is not a transactional-only service. Count billable messages rather than API calls or unique contacts. Neither a dedicated IP nor a higher plan price proves better deliverability.

Why Postal is not a $0/month managed alternative

Postal’s software license is $0; its total operating cost is unknown. You supply hosting, storage/backups, network/IP charges where applicable, monitoring and maintenance, plus delivery incident work. Postal documents at least 4GB RAM, two CPU cores and 25GB disk, with Docker, MariaDB and outbound port 25. An existing server is still a resource you operate. We preserve the free license fact and exclude Postal from known-total price rankings rather than inventing a universal hosting cost.

Choose self-hosting when you deliberately want to operate mail infrastructure. For a small app needing receipts and password resets, compare the managed-service bill with the time and responsibility you would otherwise take on.

Sources and how to check a quote

Mailgun pricing · Mailgun overage rules · Postmark pricing · Postmark pricing-selector data · Postmark billing counts · Postal prerequisites.

The current Postmark selector lists Basic 50k overage at $1.80/1k; an older comparison page still shows $1.30 for an unnamed plan. We use the current selector’s tier-specific prices. Trials, tax and optional retention/IP add-ons are excluded. Existing catalog facts outside this focused review retain their own source dates; a snapshot build date is not a fresh review of every vendor.

Open the transactional-email comparison workspace · Compare other transactional email plans · Read the estimation methodology.