Amazon has sent a shot across the bow of MongoDB today as it announced a document database with Mongo compatibility.

The launch of AWS DocumentDB – a fully managed document database service – comes just months after MongoDB announced a new licence aimed at stopping cloud giants ripping off its database.

DocumentDB – curiously named, given that what is now Microsoft's Azure CosmosDB was known as DocumentDB until 2017 – has taken Amazon two years to develop, according to non-relational database veep Shawn Bice.

He made no bones about the fact Amazon spent a lot of time looking at how to support MongoDB workloads, but ultimately decided to "build a new purpose-built document database from the ground up" that supported MongoDB APIs.

Fed up with cloud giants ripping off its database, MongoDB forks new 'open-source license' READ MORE

Amazon admits in its PR bumf that its customers "use and like" MongoDB, but paints the smaller firm's tech as complex and hard to scale.

It claims customers "find it challenging to build performant, highly available applications... that can quickly scale to multiple terabytes and hundreds of thousands of reads and writes-per-second".

This, it said, is "because of the complexity that comes with setting up and managing MongoDB clusters". The result, as Amazon would have it, is that customers "spend a lot of time and expense" managing clusters at scale on top of time spent on securing, patching and operating the smaller firm's tech.

MongoDB does have its own managed database-as-a-service, Atlas, introduced in 2017 as part of its efforts to gain a foothold in larger enterprises – the business has primarily been known as the database for devs. In its most recent results, Mongo said Atlas had 6,200 customers.

However, Amazon also dismissed this service, saying that managed MongoDB systems "face data replication challenges and they suffer from long recovery times in the event of failure".

And it seems the announcement has struck a chord with some users on Twitter, with one saying that "running a sharded MongoDB set up yourself is a PITA [pain in the ass]".

I swear to god, sometimes AWS seems to be reading either my Slack private chats or even my thoughts. Amazon DocumentDB with MongoDB compatibility layer. This is great, since running a sharded MongoDB setup yourself is a PITA. https://t.co/8nfdvytxHz — Johannes Gilger (@heipei) January 10, 2019

Amazon's head-on attack of Mongo comes after the New York startup announced in October that all future releases for its previously open-source database would be covered by a new licence – the Server Side Public License (SSPL) – that imposes conditions on companies using its tech.

This will say that companies offering SSPL software as a service have to make available the source code and modifications, as well as the source code of the applications used to run the service.

Amazon's DocumentDB implements the Apache 2.0 open-source MongoDB 3.6 API – a two-year-old version of the software that means the smaller firm can at least argue Amazon's database is based on out-of-date code.

It is also likely to ruffle more feathers in the open-source community, as Amazon's decision to rely on API compatibility suggests it wants to circumvent the SSPL and keep its code closed.

Meanwhile, MongoDB execs are remaining bullish about the new competition, with CEO Dev Ittycheria pinning a bolshy tweet to his profile this morning.

First they ignore you,

then they laugh at you,

then they try to copy you,

And then you change the world. — Dev Ittycheria (@dittycheria) January 10, 2019

He told Silicon Angle that "imitation is the sincerest form of flattery" but said devs would be "technically savvy enough to distinguish between the real thing and a poor imitation". ®