Enclosure on a Timer: Who Fair Source Is Actually Fair To

Two months ago I wrote about a licence built with the best of intentions: Mark Qvist’s bespoke Reticulum licence, which tried to shield a mesh networking stack from corporate capture and fenced off a piece of the commons in the process. That one felt like an honest mistake by a tired maintainer. This post is about a licence family that makes a similar trade on purpose, with a marketing site, a definition, a list of adopting companies, and a word chosen to make you feel good about it.

The word is “fair”. The project is Fair Source, at fair.io, and I am not a fan.

What Fair Source Actually Is

Fair Source was launched by Sentry, the application-monitoring company, on 6 August 2024, with a handful of startups signing on the same day: GitButler, Keygen, PowerSync and CodeCrafters. It answers a 2023 call from Chef co-founder Adam Jacob for a name that companies sharing their code under non-open terms could rally behind. Fourteen companies are now listed on the site.

The Fair Source Definition has three parts. The software is publicly available to read. It allows use, modification and redistribution “with minimal restrictions to protect the producer’s business model”. And it undergoes “delayed Open Source publication”, meaning each release starts under a proprietary licence and converts to an OSI-approved one later, on a schedule.

The flagship licence is Sentry’s own Functional Source License (FSL). You can do anything with FSL code except a “Competing Use”, defined as making the software available to others in a commercial product or service that substitutes for it, or that “offers the same or substantially similar functionality”. On the second anniversary of each release, that version converts to Apache 2.0 or MIT. The site also lists the Fair Core License (FSL plus licence-key support) and the older Business Source License (BUSL), which usually converts after four years.

Credit where it’s due: Fair Source does not pretend to be open source. Its own site says it is not FOSS and wants the two kept distinct. That honesty is more than some relicensing companies have managed, and Sentry’s code is genuinely readable, which beats a closed binary every time.

The honesty stops at the name.

The Word Doing the Work

A label is only worth what it costs to earn it, and who gets to set the price. Anyone who has sold produce knows this. Fairtrade means something on a bag of coffee because the people growing the coffee hold half the votes in Fairtrade International’s General Assembly, a share producers fought for and won in 2013. A Geographical Indication like Barossa or Chianti Classico means something because a consortium of growers in that place wrote the rules and police them, a point I made at length in Not a Single Local Drop. The label protects the people with the least power in the transaction, and they are the ones who decide what it means.

Now look at who decides what “fair” means in Fair Source. The project’s own README says governance is “fairly lightweight”: two people, one from Sentry and one from Keygen, manage company and licence submissions, and Sentry’s co-founder David Cramer “sets high-level direction and intent”. The Open Source Initiative’s survey of delayed-publication licensing, the history Fair Source cites to give the idea standing, was itself funded in part by a donation from Sentry. The definition was drafted by the vendors who use it, to describe a licence one of them wrote, for a business model they share.

That’s not a certification. It’s a trade association naming its own product. If a group of supermarket chains launched a “Fair Farming” label, wrote the standard themselves, and the standard said producers could sell to anyone except a competing supermarket, nobody would mistake it for Fairtrade. Software has fewer people paying attention to the fine print, which is exactly why the word was chosen. Mark Collier of the OpenInfra Foundation put it carefully when The Register asked him in 2024 whether open source developers are fairly paid: “‘fair’ is … a very charged word”. Fair Source charged it and kept the change.

Fair to whom, then? Sentry calls its licence “freedom without free-riding”. The freedom on offer is real but bounded: read, run, modify, as long as you never compete. The thing being protected is the vendor’s market position. Developer sustainability, the value Fair Source puts on its front page, here means the sustainability of one company’s revenue. It is a legitimate thing to want. It isn’t fairness to the commons, and it isn’t fairness to the developers outside the company whose contributions it accepts.

Two Years Behind, Forever

The delayed-publication clause is the part that sounds most generous and does the least.

Every FSL release does eventually become Apache 2.0. But the clock runs per version. The day a release converts, the vendor has already shipped two years of newer releases, still under the non-compete. So the open version is always the stale one. Anyone who wants to run a competing service, which is the one freedom that matters for keeping a steward honest, gets the code minus two years of features, minus two years of performance work, and minus two years of security fixes. Those fixes are right there in the public repository, readable, and off limits for the one use that’s forbidden.

In software terms, two years is a long time. It’s the gap between a supported release and one nobody should expose to the internet. “You may compete with us using our 2024 code” is a promise the vendor can make comfortably, precisely because no serious competitor would take it up.

The Right to Compete Is the Accountability Mechanism

This is where Fair Source misreads what a commons is.

Sentry frames the competitor who forks and hosts its code as a free-rider, someone taking value without paying for it. Sometimes that’s true, and the hyperscaler that wraps a project in a managed service and gives nothing back is a real pattern. But the commons already has an answer to that, and it isn’t a non-compete. Elinor Ostrom’s work on commons governance, which this site has leaned on before, found that lasting commons manage free-riding with rules the users make, monitor and enforce themselves, with graduated sanctions, not by handing one user the right to exclude everyone else who might do the same work.

In software, the equivalent of that self-governance is the right to fork. It’s the community’s exit, in Albert Hirschman’s sense, and it’s what gives the community a voice. A steward who knows the project can be forked and run by someone else has to keep listening to users, keep shipping, and keep the licence terms reasonable. Take away the right to compete and you take away the one check the community holds over the steward. What remains is a company whose code you can read but whose decisions you can’t contest, which describes most proprietary vendors with a public GitHub page.

Enclosure by Good Intentions ended on this point: a commons is protected by how many people can fork it, ship it and keep it running without asking anyone’s permission. Fair Source sets that number, for any commercial purpose that matters, to one.

We’ve Watched This Film

Fair Source isn’t new. It’s the Business Source License move of the past five years with a definition stapled to it, and that move has a track record.

HashiCorp moved Terraform from the Mozilla Public License to BUSL in August 2023. Within weeks, Gruntwork, Spacelift, env0, Harness and others had forked it as OpenTF, and by September it was OpenTofu, hosted by the Linux Foundation. Redis dropped its BSD licence for a dual RSALv2/SSPL model in March 2024. The Linux Foundation, AWS, Google, Oracle and others forked the last BSD release as Valkey almost immediately, and in May 2025 Redis added the AGPLv3 as a licence option. Elastic left Apache 2.0 for SSPL and its own Elastic License in January 2021, AWS forked the last Apache release as OpenSearch within months, and in August 2024 Elastic added the AGPLv3.

All three companies discovered the same thing. When a vendor fences its code, the community doesn’t pay the toll. It forks the last open release and walks, and the vendor ends up competing against its own old code with a smaller contributor base. Two of the three eventually reached for the licence that was on the shelf the whole time.

The company that largely skipped the fork is the one that chose that licence first. Grafana moved its core projects from Apache 2.0 to the AGPLv3 in April 2021, to make anyone who modifies and hosts it contribute back, while staying OSI-approved. No significant fork followed, just a maintenance-only branch of the last Apache release, because there was little to escape. The AGPLv3’s network clause means a hosted competitor has to publish its changes, so the vendor’s work flows back. And the right to compete stays intact, so the community keeps its exit. That’s the bargain Fair Source refuses to make: protection from enclosure in exchange for staying open to competition.

Fair Source Comes to the Farm

Silicon Valley licence debates can feel remote from a paddock, so here’s a version closer to the work I do.

Picture a farm-data platform, the kind that pulls soil-moisture readings, yield maps and machinery telemetry into one dashboard, released under FSL. It looks like a gift. A grower co-op can download the code, run it on its own server for its own members, read every line of how its agronomic data is processed, and fix the bugs it cares about. All of that is a permitted purpose.

Now the co-op grows. Neighbouring co-ops want in, and the natural next step is to offer the platform to them as a paid shared service, the cooperative model The Cooperatives of the Soil argued for. That’s “making the Software available to others in a commercial product or service” offering “the same or substantially similar functionality”. It’s a Competing Use. The co-op can keep using the platform, but it can’t become the platform. It can help a neighbour install and run its own copy. It can’t run one for them. The version it may legally offer to other farmers is two years old.

That’s a non-compete with a farmer at the receiving end, and farmers know the shape of it. Read the repair manual but don’t fix the tractor yourself. Own the machine but not the software in it. Hold the data but don’t move it to a competitor. Thank You, Brussels covered how long it took the EU to pry open the ISOBUS and dashboard locks. A Fair Source licence on agtech would build the same lock into the code, then call it fair.

What I’d Tell a Startup Instead

The problem Fair Source names is real. Building software costs money, and watching a larger company host your work and pocket the margin is a bitter thing. I’m not arguing that companies shouldn’t protect their revenue. I’m arguing they should be honest about the trade and pick a tool that doesn’t hollow out the commons it draws on.

If you want protection from a hosted competitor taking your work private, use the AGPLv3. It does that job, it’s OSI-approved and FSF-endorsed, Debian ships it, and your users keep the right to fork, which is the reason anyone trusts you enough to build on your code in the first place. If you need a business model on top, sell hosting, support, or a commercial licence to the customers who don’t want the AGPL’s obligations. MySQL and Qt built businesses on that dual-licensing model decades ago. If you truly can’t live with anyone competing with you, then your product is proprietary. Say so, and publish the source as a courtesy if you like.

What I’d ask is that you don’t borrow a word that means something to farmers, growers and workers, and pin it on a non-compete.

There’s a harder question underneath all of this, and Fair Source at least has the merit of raising it: who pays the people who make the software? Bruce Perens, who wrote the Open Source Definition, has a very different answer, called Post-Open. Jeff Emmett’s Commons Stack has a third. Both deserve a proper hearing, and that’s the next post.

Part one of two. Next: Three Answers to Who Pays the Maker: Fair Source, Post-Open and the Commons Stack. Related reading: Enclosure by Good Intentions on AGPLv3 versus bespoke licences, and The Commons Has No Ledger for This on why free software never built a way to pay its makers.

Sources

• Fair Source, About and Licenses. The Fair Source Definition, delayed Open Source publication, and the FSL, FCL and BUSL listings.
• Fair Source, project README. Governance: managers from Sentry and Keygen; Sentry’s David Cramer “sets high-level direction and intent”.
• Functional Source License, FSL-1.1-ALv2 template. The “Competing Use” definition and the Apache 2.0 grant on the second anniversary of each release.
• Sentry, “Introducing the Functional Source License: Freedom without Free-riding”, November 2023.
• Open Source Initiative, Delayed Open Source Publication: A Survey of Historical and Current Practices, by Seth Schoen, James Vasile and Karl Fogel, funded by Sentry and OSI members.
• Fairtrade International, General Assembly and Board. Producers hold 50% of the vote.
• Linux Foundation, OpenTofu launch, September 2023, following HashiCorp’s 10 August 2023 move to BUSL. See TechTarget.
• Redis, Redis 8 adds AGPLv3, May 2025, after the March 2024 move to RSALv2/SSPL and the Valkey fork. See Phoronix.
• Elastic, AGPL added for Elasticsearch and Kibana, August 2024, after the January 2021 move to SSPL and ELv2. See heise.
• Ostrom, E. (1990). Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge University Press.
• Hirschman, A.O. (1970). Exit, Voice, and Loyalty. Harvard University Press.

• Fair Source
• Functional Source License
• Business Source License
• Open Source Licensing
• AGPLv3
• Enclosure
• Digital Commons
• Agtech