Last updated: November 9, 2026
A Mailgun alternative is worth it when one sender's bad week can hurt another, or when you can't tell which brand, mailbox provider and IP caused a drop. If you send for one brand and Mailgun's logs answer your questions, stay where you are. If you send for several brands or clients, you need them separated and each one visible.
Most teams pick Mailgun for the API and don't think about the sending side again. That works until a second brand, client or product line shares the account, and a bounce spike on one of them shows up in the numbers for all of them. This guide covers what Mailgun already does well, how its separation and visibility compare with a managed alternative, and what to ask before you change providers.
Two terms run through the rest of the post. Separating means each brand sits on its own domain, IPs, pool, warmup plan and throttles, so a problem in one stays in that one. Seeing means you can tell what happened at each mailbox provider (Gmail, Yahoo, Microsoft and the like), per brand and per IP, down to the bounce code, and what to fix next.
What does Mailgun already do well?
Mailgun gives developers a REST API and SMTP relay, verified sending domains, inbound routing and a free plan of 100 emails a day. Its 100,000-email plan keeps logs for 30 days, adds dedicated IP pools and includes live phone and chat support. For one brand with a developer-led setup, that's a complete foundation.
Most Mailgun alternative lists skip that, so here it is plainly. Mailgun's pricing page, checked 2026-11-09, includes inbound routing on every plan, from 1 route on the free plan to full access at 50,000 emails a month. In our experience the API and documentation are easy to work with. Mailgun also sells inbox placement testing and reputation monitoring as a separate product called Optimize.
It also covers more separation than people assume. The IP Pools help article, checked 2026-11-09, recommends splitting marketing and transactional mail by domain and by IP, and describes a pool per client for agencies and resellers. If you send for one brand, or for a few clients who each get a domain and a pool, you may not need anything else.
How do Mailgun and SendX Infrastructure compare on separation and visibility?
Mailgun separates mail by sending domain and IP pool, and extra dedicated IPs cost $59 a month each beyond the one included from 100,000 emails a month. Its log windows run from 1 day to 30 days by plan. SendX Infrastructure separates by sub-account, with throttles for 27 mailbox providers, and drills from sub-account to IP to mailbox provider to SMTP code.
| Question | Mailgun | SendX Infrastructure |
|---|---|---|
| What's the unit of separation? | A sending domain assigned to an IP pool of dedicated IPs. Pools can map to a mail type or a client. | A sub-account per brand, client or tenant, with its own API key and domains, plus IP pools chosen by use case. |
| What's the dedicated IP policy? | Access from 50,000 emails a month, one included from 100,000, extra IPs $59 a month each. | Dedicated or shared IP pools set per brand, through the software or the API. |
| How long do logs last? | 1 day on the free and 10,000-email plans, 5 days at 50,000, 30 days at 100,000. | Stats zoom from day to hour to minute, and minute-level data is kept for 7 days. |
| What can you see per brand, mailbox provider and IP? | Analytics and reporting are included. Reputation monitoring and inbox placement are part of Optimize. | Drill-down from sub-account to IP to mailbox provider to SMTP code, with Google Postmaster data and blocklist status for IP, domain and tracking domain beside it. |
| Does it process inbound email? | Yes, with 1 route on the free plan up to full access from 50,000 emails a month. | No. |
| Who answers when something breaks? | Live phone and chat support on the 100,000-email plan. | First response within three hours on a work day, with an executive and an engineer on the first call. |
Sources: Mailgun's pricing page and IP Pools help article, both checked 2026-11-09. SendX Infrastructure column from the SendX Infrastructure product pages and internal product documentation, November 2026.
Most teams assume a dedicated IP means separation. It doesn't when every brand sends from that one IP. Gmail tracks volume and feedback per domain and IP address, and Gmail's sender guidelines say the IP quota is shared by every domain that sends from it. One brand hitting the limit can stop all of them.
Mailgun's separation is real, so the gap to test is visibility per brand. Pick one brand and ask for its delivery to Gmail, Yahoo and Microsoft over the last 7 days, split by IP, without exporting events into a BI tool. The full Mailgun and SendX Infrastructure comparison goes further.
Is Mailgun or SendGrid the better choice?
Neither wins by default. Mailgun suits developer-led teams that want an API, inbound routing and published log windows of 1 to 30 days by plan. SendGrid suits teams that want one account for application mail and marketing campaigns. Which one holds up depends on how many brands share the account and how much per-sender reporting you'd have to build yourself.
Compare them on your own use case rather than a score. Our scored comparison of six transactional email APIs covers features, uptime and price per 1,000, and we won't repeat that table here.
The multi-brand question is where the two diverge most. Teams that send for several brands report that SendGrid pushes a choice between keeping every sender in the parent account or giving each one a sub-account. They also report that results across sub-accounts often have to be exported by webhook into a BI tool to roll up. Mailgun splits by sending domain and IP pool instead, so test the roll-up in a trial account of whichever you consider.
If brands can't be separated or seen, moving from one to the other mostly moves the problem. Our SendGrid comparison and SendGrid pricing guide cover the other side.
What should you check first when inbox trouble shows up?
Check in this order: infrastructure, data quality, content, then engagement and traffic shape. Read the headers on a test message and run your domain and IPs through blocklist lookups first. If delivery dropped overnight, check DNS records before anything else, because a DNS host change can silently remove your SPF, DKIM or DMARC records.
Our deliverability team works in that order.
- Start with infrastructure. Read a test message's headers for authentication and one-click unsubscribe, then run your domain and IPs through blocklist lookups.
- Move to data quality. Compare hard bounces, then soft bounces, and read the first email new contacts receive.
- Then check content. Look for broken links, oversized images and spam-filter scores.
- Finish with engagement and traffic shape. If the first three are clean, the cause is usually a volume spike or unengaged recipients.
Run each check per mailbox provider, because a blended delivery rate can look fine while one provider rejects you. Provider-level stats catch that sooner. Google tells senders to keep their spam rate below 0.10% and doesn't track open rates, so a falling open rate alone doesn't prove a Gmail problem. See also why emails land in spam.
What should you ask any provider before you change?
Ask four things before you change providers. Ask how the IP architecture works and whether you can see results by brand, mailbox provider and IP without exporting. Ask how opens are counted with bots removed and how you'll see Gmail's view of IPs you share. Google says it can't verify open rates reported by third parties.
- How does the IP architecture work? Ask whether shared and dedicated IPs can sit on one account and whether mail can overflow to shared IPs during warmup. A shared IP is like a co-working space, because your reputation depends partly on who else is working there.
- Can you see results per brand, mailbox provider and IP without exporting? Test it on a trial account with one brand.
- How are opens and clicks counted? Ask whether bot opens are removed and how.
- How will you see Gmail's view of your IPs? Postmaster Tools reports on domains you verify, so ask what the provider shows for IPs you share.
Whichever provider you pick, keep your current one sending while the new one warms up, move your most engaged contacts first, and budget at least a month for surprises.
Should you stay on Mailgun, separate your brands, or look elsewhere?
Stay on Mailgun if you send for one brand, volume is under about 100,000 emails a month and its logs answer your questions. Separate if several brands, clients or tenants share a sending identity and one problem could reach the rest. Look elsewhere if you want a plain relay with no conversation, or a low monthly bill matters more than anything else.
Shape matters more than size. One large brand with clean data is easier to run than five small clients with different list sources, because the five can hurt each other and the one can't.
| Your situation | What to do | Why |
|---|---|---|
| One brand, steady volume under about 100,000 a month, logs answer your questions | Stay on Mailgun | Domain and IP pool separation already covers a single brand. |
| One brand that needs inbound parsing and a tight developer workflow | Stay on Mailgun | SendX Infrastructure doesn't process inbound email. |
| Several brands or clients on one account, and you can't tell which one caused a drop | Separate, starting with one brand | Each brand gets its own rails and its own drill-down. |
| A builder under about 100,000 sends a month on a tight budget | Look at Amazon SES or SocketLabs | We don't compete on price at that size, and we'd say so on a call. |
| A team that wants a relay and no conversation | Look at SendGrid | SendX Infrastructure is built around a conversation with an email expert. |
Two of those rows send you away from us, and that's deliberate. A builder under about 100,000 sends a month gets more from a low-cost relay than from per-brand rails, and a team that wants no conversation will find ours is built around one. Separating doesn't mean leaving Mailgun on day one, as the next section shows.
How does SendX Infrastructure fit that decision?
SendX Infrastructure is managed sending infrastructure for senders with several brands, clients or publications. Each brand gets its own domain, IPs, pool, warmup plan and throttles, so one bad brand can't sink the rest. You can route one brand through it while Mailgun keeps running underneath, then move the next brand when the numbers hold, with throttles paced for 27 mailbox providers.
Doing this yourself means building the per-brand dashboards and alerts on top of whichever provider you use. SendX is the sending software, and SendX Infrastructure (formerly SendPost) is the delivery engine underneath it. You hold each brand's controls through the software or the API.
For seeing, every send is recorded per brand, per mailbox provider and per IP, down to the SMTP code, with Google Postmaster data and blocklist monitoring for IP, domain and tracking domain beside it. A report tells you the fix in plain English.
The decision is yours. If you recognize the multi-brand problem, route one brand first, compare the numbers with what you see today, and switch the routing back if we don't earn it. An executive and an engineer join the first call.
Book a call about your first brand
FAQs
Which email API is best for free?
It depends on what the free plan has to prove. Mailgun's free plan allows 100 emails a day and keeps logs for 1 day, checked 2026-11-09, which makes it a testing tier. Judge any free plan on two numbers, the daily cap and the log window. Free tiers change often, so read each vendor's own pricing page the day you compare. Don't run a brand whose reputation matters on a plan that keeps a day of logs.
Does every brand need its own dedicated IP?
No. Our deliverability team's rule of thumb is that senders above roughly 100,000 to a couple of hundred thousand messages a month belong on dedicated IPs. Smaller or inconsistent senders often do better on shared IPs, because they can't sustain a dedicated IP's reputation. Mailgun's pricing page makes a dedicated IP available from 50,000 emails a month and includes one from 100,000. A brand below those volumes can still get its own sending domain.
Does my reputation follow me when I change providers?
Your domain's reputation stays with the domain if you keep the same sending domain. IP reputation doesn't follow you, because new IPs start with no history. Google advises raising the volume of any changed traffic separately and gradually after you change your sending infrastructure. In practice that means moving one brand first, watching the numbers by mailbox provider, and moving the next brand only when they hold.
