MongoDB is gearing up to dig deeper into the mobile and serverless database worlds by spending $39m to buy Realm.

Realm claims 350 customers and 100,000 active developers for its Realm mobile database and Synchronization Platform. MongoDB has its own serverless backend database Stitch, and a mobile optimised version of its core database platform.

MongoDB CTO Eliot Horowitz said in a blog post that a combined roadmap for the two product sets would be unveiled at MongoDB World in June.

Dev Ittycheria, president and CEO at MongoDB, said in a canned statement, “This acquisition is a natural fit for our global cloud database, MongoDB Atlas, as well as a complement to Stitch, our serverless platform.”

David Ratner, CEO, Realm, explained the deal would allow Realm to continue “What we started Realm to do – helping mobile developers build better apps faster and helping both the community and enterprises support their use-cases across offline-first requirements, digital transformation, user experience and IoT. developers.”

Ratner added in a blog post, “MongoDB and Realm are fully committed to investing in the Realm Database and the future of data synchronization, and taking both to the next phase of their evolution. We believe that MongoDB will help accelerate Realm’s product roadmap, go-to-market execution, and support our customers’ use cases at a whole new level of global operational scale.”

In his own blog post, MongoDB CTO Eliot Horowitz wrote, “Every time I’ve extolled the virtues of MongoDB for just getting out of your way and letting you work, I might as well have been talking about Realm.”

Which would make you wonder whether Mongo will stop talking about its own mobile and serverless platforms at all, if both firms weren’t at pains to point out how “complementary” their products are.

Horowitz continued, “One key principle guiding that process is simple: we will not introduce backwards breaking changes.”