Bitcoin CoreDev reflections 2021-2022
by Adam Jonas


  • bitcoin
  • coredev
  • retro

For a third year running, regular Bitcoin Core contributors received a survey to surface priorities and ensure that people feel that they can contribute effectively. Below is a summary of the results in a format similar to last year’s survey.

2021 Activity

  • 1785 PRs were opened against the master branch (compared to 1928 PRs in 2020, 1789 in 2019, 1910 in 2018, 1716 in 2017)
  • …1261 PRs were merged against master (1257 PRs in 2020, 1167 2019, 1244 in 2018, 1152 in 2017)
  • …from 144 unique PR authors (151 in 2020, 149 in 2019, 179 in 2018, 143 in 2017)
  • …including 68 first-time authors (76 in 2020, 71 in 2019, 115 in 2018, 92 in 2017)
  • …there were 35157 review comments (41352 in 2020, 32868 in 2019, 31989 in 2018, 27598 in 2017)
  • …from 332 regular reviewers* (346 in 2020, 311 in 2019, 347 in 2018, 321 in 2017)
  • …and 471 first-time reviewers (408 in 2020, 443 in 2019, 667 in 2018, 556 in 2017)

*A regular reviewer must have left >= 5 comments

The Questions

The questionnaire consisted of 13 questions, which included:

  • How happy were you with progress in Bitcoin Core in 2021? (score 1-5 with comment. 1 = unhappy, 5 = happy). Try to think about what your hopes for this year were at the start of the year and whether that happened.
  • How happy were you with your own contributions? (score 1-5 with comment. 1 = unhappy, 5 = happy). Again, try to think about what you were hoping to achieve at the beginning of the year and whether that happened.
  • What went well in 2021? This can be about the project or process or your individual achievements.
  • Is there anything that frustrated or disappointed you about the Bitcoin Core project or your own contributions in 2021?
  • What do you hope will happen in Bitcoin Core in 2022? Try to rank your priorities.
  • What do you personally hope to achieve with Bitcoin Core in 2022? Try to rank your priorities.
  • Is there anything you’d change about the process/project that would help those things happen?
  • What is one thing would make you happier or more productive?
  • How connected do you feel to the other contributors of the project? Do you have any ideas on how to better sync with them?
  • Would you be willing to mentor another contributor? (Mentoring can mean a lot of different things, this is a rough way to gauge interest)
  • What aspect of Bitcoin or Bitcoin Core would you like to learn more about?
  • What topics would you like to discuss at the next CoreDev event?
  • Anything else?

The responses

24 contributors completed the survey. A word cloud from their comments is posted as a banner at the top.

When asked to rate how happy they were with the project in 2021 (on a scale of 1-5), the mean declined slightly to 3.71 (3.77 in 2020, 4 in 2019), and the median remained at 4 (4 in 2020, 4 in 2019).

Highlights from 2021 included

  • Taproot merged and activated +8
  • Spent more time reviewing work compared to last year +3
  • CoreDev in Zurich +2
  • Personal funding +1
  • GUIX +1
  • Progress on libbitcoinkernel +1
  • CJDNS +1
  • No major bugs found in releases +1
  • Mentorship +1
  • Fanquake doing point releases
  • Hardware wallet progress
  • QML repo
  • OSS-Fuzz
  • I2P, Tor v2/v3

When asked to rate how happy the respondents’ were with their personal 2020 contribution (on a scale of 1-5), the mean rose slightly to 3.54 (3.41 in 2020, 3.55 in 2019), and the median remained at 4 (4 in 2020, 4 in 2019).

Areas of frustration/disappointment in 2021 included

  • Taproot activation +3
  • Review process +3
  • Politics and favoritism seeping into review +3
  • Slow pace +2
  • Decline of regular contributors/ maintainers stepping down +2
  • Lack of progress on meaningful projects
  • More visibility into what others are working on
  • PR review/IRC noisy at times

Regarding Goals/Priorities for 2022

  • Covenants +4
  • Miniscript +3
  • Assumeuxto +3
  • Erlay +2
  • QML-based GUI +2
  • BIP324 +2
  • Another year of no major breakage +1
  • BIP 322 +1
  • libbitcoinkernel +2
  • Apple M1 release binaries
  • Linux release binaries with Wayland support
  • Differential fuzzing
  • Progress with process separation / code organization
  • Introduce Rust in the codebase
  • Multiprocess indexing

Changes to improve the process/project

  • Organizing on-boarding resources and continued investment in educational and on-boarding resources
  • Contributors should be evaluated based on the quality of their contributions
  • Maintainers are per-codebase-area (e.g., build, GUI, mempool, p2p, wallet, fuzzer, RPC) and not “general” maintainers
  • More developers
  • More meetings. Video meetings might be fun
  • A clear set of priorities that would unify contributors


When asked whether they would be willing to mentor:

  • 67% responded, “yes, that is of interest”
  • 33% answered, “no, it wasn’t for them”

Interested in Learning More About

There were a number of topics that contributors would like to learn more about, including:

  • P2P +3
  • Mempool +2
  • Wallet +2
  • Consensus +2
  • Covenants +1
  • Cryptography
  • Process separation
  • Script
  • Validation
  • Taproot

At the next

  • Multiprocess/process separation +1
  • Covenants +1
  • libbitcoinkernel
  • Deprecating the legacy wallet
  • Miniscript
  • Musig2
  • Hardware wallets
  • P2P
  • Script design
  • Fuzz testing
  • Spacechains
  • CPFP / RBF work
  • Policy documentation


Review (again) was a common theme found in the answers. The word ‘review’ was the most popular topic appearing even more times than the word ‘bitcoin.’

There were a few different flavors of problems, starting with a general dissatisfaction with the management of review:

  • “The review process needs to be more streamlined and explicit. There is a tendency for PRs to drag on for much longer than needed because of style changes.”
  • “So I would be happier if the review process of PRs were more predictable or faster. I know there are many good reasons for that. Still it makes me contribute less than I would normally do.”
  • “It’s totally unknown whether anybody will actually review your PR or not. One may get a burst of review comments and then nothing really can happen for weeks or months.”
  • “If a PR gets several ACKs, it can take weeks for the PR to be merged… To me the process is very unpredictable.”

There was also an acknowledgment of the impact of not getting review:

  • “A few people seem to have a sense of entitlement about review of their work”
  • “People also make comments about others’ PRs being merged ‘suspiciously fast,’ interpreting this as favoritism or dishonesty by the authors, without having any substantial criticism of the PR itself.”
  • This was perhaps best summarized by the comment, “In general, I think we all experience a lack of review attention within our group of developers, and perhaps this creates tension. But collaboration, not competition, is what helps make us more productive.”

Others noted they wished that they had done more review:

  • “I wish I had done more reviews more promptly.”
  • “I’ve been getting sucked into projects and not reviewing enough. Or sometimes I get hung up on reviewing a big PR, and neglect other smaller PRs that could be making progress. I need to get better at task switching”
  • “I also thought [important projects] would have moved forward more in 2021, but I was remiss in not reviewing them enough myself.”


While there was frequent mention of celebrating the activation of taproot, frustration around the taproot activation process was also apparent.

Till next year…

Thank you to the contributors that took the time to write up their responses. My hope is that this can be a useful reference for prioritization and process improvements, and I look forward to reporting on a similar survey in early 2023.