SendGrid and Mailgun are the closest pair in this comparison set: both are established providers, both send from shared IP pools by default, both offer dedicated IPs, and both will handle serious volume. The differences are in what else they do, how they price it, and how much of the platform you end up using.
Both providers default to shared IP pools. Your sending reputation is partly the reputation of other customers on the same IPs, and both offer dedicated IPs on higher tiers with the usual warmup period. If you are choosing between these two for deliverability reasons alone, the honest answer is that they are similar. The deciding factors are the rest of the platform.
SendGrid leans into the full email stack: transactional plus marketing campaigns, templates, A/B testing, segmentation, a large SDK ecosystem, and a free tier. If your product will grow into marketing email, SendGrid keeps you on one platform.
Mailgun leans into raw sending: a clean API and SMTP, competitive pricing at volume, custom domains, and fewer marketing features. Teams that send mostly transactional mail and want a cheap, flexible pipe tend to land here.
Both are API-first with webhooks for bounces, complaints and clicks. SendGrid has more integrations and more documentation surface. Mailgun is slightly leaner and has historically been cheaper at the high end of volume. Neither is hard to use; both have enough configuration that you should read the defaults before switching them.
Both price by monthly volume with free tiers, and both get cheaper per email as you scale. Mailgun has generally been the cheaper one at high volume, while SendGrid bundles more marketing capability into the price. Check current numbers for your exact volume before you commit.
Pick SendGrid if you will send marketing campaigns as well as transactional mail, or if you want the bigger ecosystem. Pick Mailgun if you want a cheap, flexible sending pipe and will keep the marketing elsewhere. And because both share IP pools, the SPF, DKIM and DMARC setup on your domain is what you can actually control. Check it in 30 seconds.
Whichever provider you pick, the setup on your domain decides the outcome.
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