Mailgun vs SendGrid for SaaS: Pricing and Fit (2026)

Prices checked 7 October 2026; each price links to the vendor page it came from. Both vendors price by monthly volume with a slider, so the figures are what each page displayed at the stop named.

Mailgun and SendGrid are the two names SaaS teams most often shortlist for application email: password resets, invitations, invoices, usage alerts. They overlap on the core job (an HTTP API and SMTP relay, webhooks, logs) and differ in what surrounds it. Mailgun's plan cards lead with inbound routes, validations and log retention. SendGrid's lead with volume bands, and its marketing campaigns product is priced and sold separately on its own page.

The question to settle first is therefore not which one is cheaper in the abstract, but which of three jobs you actually have: sending only, sending plus receiving and validating, or sending plus a contact list that marketers email.

What each one costs at 10,000, 50,000 and 100,000+ emails

Mailgun's plans bundle a monthly allowance and then charge per extra 1,000, with the per-1,000 rate falling as you go up the plans. SendGrid's selector jumps by volume band instead. The slider readouts below are the safest way to compare, because Mailgun's own overage rates do not reproduce its slider prices.

Three conclusions fall out of the table. First, a product sending 50,000 transactional emails a month pays $15.05 less on SendGrid Essentials ($35 minus $19.95). Second, once you want a dedicated IP, the plans converge: Mailgun Scale at 100,000 is $90 and SendGrid Pro at 100,000 is $89.95, and both list dedicated IP access. Third, at the top of the ranges the two are close per email, so choose on features, not on the last few dollars.

What the cheaper plans leave out is worth reading before you sign. Mailgun Foundation keeps logs for 5 days and messages for 1 day; Scale keeps logs for 30 days and messages for up to 7. If your support team investigates "I never got the invite" tickets a week later, Foundation will not have the log. SendGrid's Essentials is the plan without dedicated IPs, which only matters when you send enough mail that sharing an IP pool hurts you.

Adding marketing changes the maths. SendGrid's Marketing Campaigns page reads Basic at $25 for 10,000 contacts (30,000 emails a month) and $50 for 20,000 contacts, so 10,000 contacts plus 50,000 transactional emails is $25 plus $19.95, or $44.95 a month, in two products from one vendor. On Mailgun the same load is $35 for sending and a separate bill for whatever tool runs the campaigns.

Where Mailgun is the stronger fit

Inbound handling is the clearest difference on the pricing pages. Mailgun lists inbound routes on every plan and full access from Foundation, which suits products where users reply to a notification and the reply must land in a thread, a ticket or a comment. If that feature is on your roadmap, Mailgun's pricing page already tells you the limit you will hit: 5 routes on Basic.

Validation is the second. Mailgun's Scale plan includes 5,000 address validations, with overage from $0.80 per 100, and the other paid plans charge $1.20 per 100. A product with an open signup form and a free trial tends to collect typos and throwaway addresses; validating at signup protects your sender reputation before the first welcome email goes out. At $1.20 per 100, checking 3,000 new signups in a month costs 30 × $1.20 = $36 on Basic or Foundation.

The free plan matters for early SaaS, too. Mailgun's 100 emails a day does not expire, while SendGrid's equivalent is a 60-day trial. A pre-launch product with a few dozen test users can stay free on Mailgun until real traffic arrives. The cap is per day, so a burst of invitations on launch day is the thing to check.

Where SendGrid is the stronger fit

SendGrid's advantage is two products under one vendor. Its Email API handles application mail, and Marketing Campaigns handles lists, with a free plan for up to 2,000 contacts and 6,000 emails a month and paid plans from $15. A founder who wants a monthly product update and a receipt flow in the same account can keep both there without adding a vendor.

It is also cheaper at the volumes most growing SaaS products start from, if you do not need Pro features. At 100,000 emails a month Essentials is $34.95 against $75 on Mailgun Foundation. The trade-off is that SendGrid's pricing page prints no overage rate for Essentials, so budget with headroom or ask sales what happens when a month runs over.

Be careful with the campaign product. It is built for contact lists and broadcasts. It does not decide that a user who invited nobody after five days should get a nudge, and nothing on its pricing page promises event-triggered lifecycle journeys. Treat it as a newsletter tool, not as onboarding automation.

Moving from one to the other

Both directions begin with DNS. Add the new vendor's SPF and DKIM records for your sending domain while the old ones are still in place, confirm the domain verifies, and leave both live for the overlap. Mailgun's Free and Basic plans include a single custom sending domain, so a product that sends from several domains will need Foundation (1,000 domains) before it can finish the move.

Next, bring across the suppression data. Export bounces, complaints and unsubscribes from the old account and import them into the new one before the first send, otherwise people who opted out will receive mail again. Then repoint webhooks: both vendors send event callbacks for delivery, bounce and complaint, but the payload fields differ, so update the handler that marks users as undeliverable and test it against a seed address that bounces.

Move traffic in order of risk. Start with a low-stakes stream such as weekly digests, then receipts, and finish with password resets and invitations once the new sender has a few days of clean history. Keep the old plan active for a full billing cycle. If you are moving from SendGrid Pro or Mailgun Scale and rely on a dedicated IP, plan a gradual ramp on the new IP rather than switching all volume on a single day.

Verdict

Pick Mailgun if the product has inbound mail, validation or per-customer sending needs, or if you want a free plan you can leave running. Pick SendGrid if you mainly send at 50,000 to 100,000 emails a month and want the lowest price on the page, or if a marketing list under the same vendor saves you a tool. For lifecycle emails that follow product behaviour, plan on a separate tool in either case.

Related comparisons: Postmark vs SendGrid, Resend vs SendGrid and Loops vs Resend. If you are leaving SendGrid, the SendGrid alternatives guide lists replacements with prices, and email platforms for developers covers API-first picks. The comparison hub lists every matchup.