Hixie's Natural Log

2024-05-03 06:28 UTC How big is the Flutter team?

I often get asked how many people contribute to Flutter.

It's a hard question to answer because "contribute" is a very vague concept. There's tens of thousands of packages on pub.dev, all of which are written by contributors to the community. There's over 100,000 of issues filed in our issue database, filed by more than 35,000 people over the years (the exact number is hard to pin down because people sometimes delete their GitHub accounts; about 700 issues have been filed by people who have since deleted their account). Many more people still have used the "thumbs-up" reaction to indicate that an issue matters to them, with almost 165,000 thumbs up from about 45,000 people. All of these people are valuable contributors to Flutter.

Usually, when pressed, people try to clarify by asking about "the core team". Again though it's hard to say exactly what that means, but let's assume they mean "people with commit access". That is, people we trust enough to have added to the GitHub repo as collaborators. This includes people who work on Flutter for companies like Google, Canonical, or Nevercode, and it includes people like me who are self-employed and/or contribute to Flutter on a volunteer basis. Currently that's about 280 people. So is that the answer? Well, no, not really. Some people have commit access but aren't active (maybe they got access because of their employer, but were then reassigned to work on another project, and the bureaucracy hasn't caught up with them yet — we only audit the membership occasionally because it's rather tedious to do). Some people have been very active recently but don't have commit access (e.g. because they were just laid off and a bot automatically removed their access; they might even resume working on Flutter in the future, as a volunteer or funded by another company).

So what's the answer?

I recently drilled down through our data to see if I could answer this. I will caveat the following numbers by saying that this changes all the time. We added a new team member just today (hi Nate!) who is not counted as a team member in the following numbers because we collected the data a few weeks ago (it takes literally days to scrape all the data from GitHub, and then hours to explore the resulting very large and very slow spreadsheet). Also, some of my definitions are a bit arbitrary, and slightly tweaking the limits would probably change the numbers noticeably.

First, I collected a list of everyone who has ever created an issue, commented on an issue, put an emoji reaction on the first comment of an issue, or submitted a PR, excluding bots and people who deleted their GitHub account. (Actually Piinks did the actual data collection. Thanks!) I limited this to a subset of the GitHub repos of the flutter org that is relatively inclusive but does not count everything (we have a lot of historical repositories and so forth). This finds about 94,357 people. (So there you go. The Flutter team is about a hundred thousand people!)

To avoid padding the numbers with people who left the project long ago, and to avoid counting "drive-by" contributors who came, did a bunch of work, and then left, I then limited the data set to people who contributed over a period of more than 180 days, and who last contributed sometime in 2024. Because of the definition of "contributed" described above, that means that someone who added a thumbs-up to an issue in December 2020 and then filed an issue in January 2024, and did nothing else, is included, but someone who submitted two PRs in March 2024 is not. Like I said, this is a bit arbitrary. Anyway, that leaves 3,839 people, of which 182 currently have commit access, 27 once had commit access but don't currently (these are mainly people who either got laid off recently and had their commit access revoked by an automated process, or people who were once team members, left, lost access from inactivity long ago, and then later came to comment on issues or file new issues — it's surprisingly common for people who once worked on Flutter full time to stick around even when their employment changes), and about 3,627 people who have never had commit access.

Of those who have never had commit access, 2,407 have filed at least one issue or submitted at least one PR (accounting for a total of 12,383 issues and 2,613 PRs). Of those, 341 have filed 5 to 9 issues (2,242 issues total), and 296 have filed 10 or more issues in their lifetime (7,021 total issues). Similarly, of the "never had commit access" cohort, 73 people have sent 5 to 9 pull requests in their lifetime (458 total PRs) and 47 have sent 10 or more (1,321 PRs total). (For context, 4,663 people have ever submitted a pull request, and 429 have ever submitted more than 10 PRs.)

Of the people who currently have commit access, 98 people have submitted more than one PR every 3 weeks on average since they first got involved (accounting for 49,173 PRs), 75 people have closed at least one issue every 3 weeks (accounting for 48,490 total issue closures), of which 10 are not in the first group (mostly that's our triage team), and 150 people have commented at least once every 3 weeks.

A follow-up question a lot of people ask is "do they all work for Google?".

This is a surprisingly hard question to answer. There are a lot of weird edge cases. For example, one person worked on Flutter for a company that Google hired to work on Flutter, but then quit that company, asked for their commit privileges to be removed, but continued to be active in the community. Several people who have quit Google (such as myself), or been laid off by Google, have continued to be active in one sense or another (I think I submit more code to Flutter now than I did in my last year at Google).

It's also hard to answer because a lot more people at Google contribute to Flutter than just those on Google's Flutter team, and a lot of people on Google's Flutter team contribute in ways that don't show up on GitHub (e.g. product management, marketing, developer relations, internal tooling).

Of the 98 people who have commit access, have been active for more than 180 days, have contributed at least once this year, and have submitted more than one PR every 3 weeks on average for the entire time they've been contributing, I estimate (based on what I know of people's employment and so forth) that about 85% are Googlers or somehow get their funding from Google, and about 15% are currently independent of Google. (This is by no means the entirety of the Google team contributing to Flutter; as I mentioned earlier, many folks at Google working on Flutter don't appear in these statistics.)

I'm not sure what conclusion to draw from this; it's both more people than I expected to see funded by Google, which is great, and fewer people that aren't funded by Google, which is less great. On the other hand, it's still a significant number of non-Google-funded people.

Is it enough? I think that really depends on what your goals are. I think if your goal is for Flutter to be an order of magnitude better than other UI frameworks, then frankly no, it's not enough. There is a ton of work to be done to get there. We know what it would take, but we don't have the people to do it today. On the other hand if your goal is to be a great framework, on par with others, then it's probably adequate. It would certainly be difficult to continue to be great with fewer people today. Of course, that may change as we complete big efforts, or as we take on new ones, or as the landscape changes, it's all hard to predict.

That said, I would love to see more direct contributions from non-Google sources, if for no other reason but to end this silly "will Google cancel Flutter" line of questioning that has followed the project since its inception. It's a dumb question. Flutter's an open source UI framework. It will never die. It will become old and something else will shine brighter one day, just as happens with literally every other UI framework ever. That's just how our industry works. There's no reason to believe that'll happen any time soon though, and certainly no reason for it to happen earlier for Flutter than any other modern UI framework.

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