An open-source pedigree came with a shrinking retention rate

The record

On 1 June 2021, Confluent, Inc. filed a Form S-1 with the Securities and Exchange Commission ahead of its Nasdaq listing, under the accession number recorded in the SEC's filing index. The registration statement states that Confluent's founders are the original creators of Apache Kafka, the open-source event-streaming project, and that the company built a commercial cloud and platform business on top of it. The filing reports revenue of $149.8 million for fiscal 2019 and $236.6 million for fiscal 2020, rising from $50.9 million to $77.0 million between the first quarters of 2020 and 2021, and a net loss of $229.8 million for fiscal 2020. Customers paying at least $100,000 in annualized revenue grew from 374 in March 2020 to 561 in March 2021, and customers above $1 million grew from 33 to 60 over the same window.

What the documents establish

The S-1 is a verified filing signed under penalty of securities law, not a founder blog post, and its figures carry that weight. It discloses a dollar-based net retention rate, the filing's own metric for revenue growth from an existing customer cohort over twelve months, of 134 percent as of 31 December 2019, 125 percent as of 31 December 2020, and 117 percent as of 31 March 2021. The filing does not spell out the calculation in the summary passage; it points to a separate section for the formula. What is unambiguous is the direction: three consecutive readings, each lower than the one before.

The filing also discloses the mechanism Confluent uses to keep a commercial edge over the open-source project it did not build alone: the Confluent Community License, described as permitting developers to use its source code while barring competitors, including cloud vendors, from repackaging it as a rival service. That license term is Confluent's own characterization, not a court's finding.

The operating read

A founder pedigree in an open-source project is a distribution advantage, not a retention guarantee. The declining net retention rate sits inside a filing that also shows revenue still growing quickly and net losses still large, which is ordinary for a company scaling around an IPO. Reading the two figures together, rather than the growth headline alone, is what a filing is for. Editorially, a buyer or investor evaluating an open-core company should treat a licensing restriction on cloud vendors as a business decision under contest, not a settled legal shield, since terms like this one have been tested elsewhere.

What to check before you decide

Before drawing conclusions from a similar open-core filing, check three things against the primary document itself.

• Does the filing define the retention metric precisely enough to compare it across periods, or only across its own reports?
• Is the open-source project's governance separate from the commercial entity, or does one company control both?
• Does a licensing restriction on competitors appear as a stated business term, or as untested legal language?

None of this makes Confluent's structure unusual among open-core companies going public in the same period; it makes the S-1 the place to verify the numbers rather than the founding story.