Weekly Check-in: Week of 2026-06-01

[payjoin-bot]

Weekly standup — each contributor has a thread below with auto-gathered activity.

Reply to your thread by end-of-day Monday (your timezone). Copy the template below and fill it in:

### Shipped
<!-- Add anything the bot missed: design work, specs, conversations, off-GitHub contributions. Correct any mistakes. Skip if the bot covered everything. -->

### Focus
What are you working on this week?

### Bottleneck
What is the single biggest bottleneck in progress toward your greater goal?
Name your goal. Name the constraint. Name who or what can unblock it.

Participated: @benalleng, @zealsham, @Mshehu5, @0xZaddyy

[payjoin-bot]

DanGould

@DanGould

Shipped

PRs reviewed:

• docs(typo): oblivous -> oblivious
• chore: add lcov.info to root .gitignore

Issues opened:

• RelayManager does not completely manage relays

Last Week

Review your previous thread: Last week's thread

[payjoin-bot]

spacebear21

@spacebear21

Shipped

PRs merged:

• chore: update flake.lock

PRs reviewed:

• Register recursive type helpers
• Complete callback interface followups
• Fix resume succeding prematurely

Last Week

Review your previous thread: Last week's thread

[payjoin-bot]

arminsabouri

@arminsabouri

Shipped

PRs merged:

• Scrubber crate skeleton

PRs reviewed:

• Join and PartialJoin traits
• scrub: some left over fixes
• nix: deny unused lint group in dedicated flake check
• scrub: HEAD detection for colocated jj repos
• scrub: report VCS errors instead of silent swallow
• nix: cargo doc check
• nix: crane check improvements
• cargo workspace layout
• Add radix-ness classifier as first step of the radix lower-bound path
• Light refactor to v2 receiver for readability
• scrub: skip flake checks for conflicted commits
• prop-tests and unit-tests feature flags
• scrub: require -- argument separator
• forbid(unsafe_code)

Last Week

Review your previous thread: Last week's thread

Auto-detected signals:

• PR awaiting review: WIP - Scurbber crate
• PR has requested changes: Add honest overview

[payjoin-bot]

benalleng

@benalleng

Shipped

PRs merged:

• Nixify ffi CI

PRs reviewed:

• FFI: Refactor Javascript integration test
• docs(cli): update relay url
• FFI dev shell follow-ups
• Add tests for OriginalPayload and PsbtContext
• fix(cli): v1 config rejecting endpoints without explicit port
• Light refactor to v2 receiver for readability
• Bump idna from 3.10 to 3.15 in /payjoin-ffi/python
• chore: update flake.lock

Issues opened:

• How should the payjoin-cli handle the latest payjoin-mailroom behavior

Last Week

Review your previous thread: Last week's thread

[benalleng]

Shipped

Focus

• Going to try and take some guidance ownership of the payjoin-cli relay refactor as there are several PRs and issues that while not blocked by each other I think could use some merge coordination so they don't all sit in limbo. starting with my Split resume session relays #1399 PR
• Still waiting on in writing liana feedback but have received some out of band feedback already so we are making progress

Bottleneck

• Review cycles could be a little slow with spacebear out of town but I will try to do my best to keep everything moving.

[payjoin-bot]

chavic

@chavic

Shipped

PRs merged:

• FFI dev shell follow-ups
• Register recursive type helpers
• Complete callback interface followups

PRs reviewed:

• Nixify ffi CI

Last Week

Review your previous thread: Last week's thread

[chavic]

Shipped

Merged BTCPay Payjoin plugin:

• Align plugin with renamed FFI bitcoin types and units. Align plugin with renamed FFI bitcoin types and units ValeraFinebits/btcpayserver-payjoin-plugin#32
• Handle initialized Payjoin poll timeouts quietly. Handle initialized Payjoin poll timeouts quietly ValeraFinebits/btcpayserver-payjoin-plugin#30
• Remove template database scaffolding. Remove template database scaffolding ValeraFinebits/btcpayserver-payjoin-plugin#31
• Add release mode for FFI package generation. Add release mode for FFI package generation ValeraFinebits/btcpayserver-payjoin-plugin#33
• Add restart replay integration coverage. Add restart replay integration coverage ValeraFinebits/btcpayserver-payjoin-plugin#34

Merged uniffi-dart:

• Complete callback interface follow-ups. Complete callback interface followups Uniffi-Dart/uniffi-dart#137
• Register recursive type helpers. Register recursive type helpers Uniffi-Dart/uniffi-dart#138

Merged rust-payjoin:

• FFI dev shell follow-ups. FFI dev shell follow-ups #1587

Reviews:

• Reviewed and approved Valera's accounting bridge / unify receiver outputs. feat: Add accounting bridge and unify receiver outputs ValeraFinebits/btcpayserver-payjoin-plugin#41
• Reviewed Nixify ffi CI. Nixify ffi CI #1574

Cleanup uniffi-dart:

• Filed uniffi-dart beta readiness roadmap. Beta readiness roadmap Uniffi-Dart/uniffi-dart#141
• Stale-issue triage pass across uniffi-dart closed: Implement HashMap/Map Type Support Uniffi-Dart/uniffi-dart#63 Implement Sequence/List Collection Types Uniffi-Dart/uniffi-dart#67 Add Dictionary Default Values Support Uniffi-Dart/uniffi-dart#68 Add Missing Build Dependencies Uniffi-Dart/uniffi-dart#74 Fix flaky async tests Uniffi-Dart/uniffi-dart#105 Follow-up: finish callback compound-type coverage and CI integration Uniffi-Dart/uniffi-dart#118 dart_async sleep timing test is too strict and fails on clean runs Uniffi-Dart/uniffi-dart#123

Focus

BTCPay Plugin:

• Progress demo video (snapshot).
• Code, process and UX review clarified, after a snapshot of what's working so far (and anticipating feedback). These tasks split into UX-side work and refactors/correctness issues. This week correctness takes priority; I'll update todos and issue trackers with findings before I begin. Ideally after [PR #41](feat: Add accounting bridge and unify receiver outputs ValeraFinebits/btcpayserver-payjoin-plugin#41).

Clearing past backlog:

• Technical article, apply insights from comments.
• uniffi-dart callback interface coverage — rewrite the callbacks-test fixture to be generic. Implement Callback Interface Support Uniffi-Dart/uniffi-dart#65
• Convert payjoin-cli E2E into a default CI-covered sender/receiver loop.

Blockers

• [uniffi-dart #136](Test Nix dev shell setup Uniffi-Dart/uniffi-dart#136) needs approval on benalleng's requested formatter changes.
• [BTCPay plugin #41](feat: Add accounting bridge and unify receiver outputs ValeraFinebits/btcpayserver-payjoin-plugin#41) also waiting — needs re-ack after squashed commits.

[payjoin-bot]

zealsham

@zealsham

Shipped

No activity found.

Last Week

Review your previous thread: Last week's thread

Auto-detected signals:

• PR awaiting review: Delegate http tracing to tower middleware
• PR has requested changes: Fix resume succeding prematurely
• PR has requested changes: OHTTP keys should be rotated

[zealsham]

Hello @nothingmuch ,@xstoicunicornx and @benalleng , your opinion on this would be really appreciated

[va-an]

Are there other consumers of payjoin::io::fetch_ohttp_keys asking for cache headers? Would rather avoid a breaking change for the sake of one caller.

Third option - add a new function returning a small typed subset of cache headers alongside the keys, like:

pub async fn fetch_ohttp_keys_with_cache(
    ohttp_relay: impl IntoUrl,
    payjoin_directory: impl IntoUrl,
) -> Result<(OhttpKeys, CacheHeaders), Error>

No breaking change, no leaking the full HeaderMap, and payjoin-cli gets what it needs.

This slightly bloats the API, but as a follow-up we could mark the old function #[deprecated] and give consumers a path to migrate to the new variant.

[xstoicunicornx]

Does payjoin-mailroom support configurable key expiry and sending accurate cache headers? If not I would think this needs to be implemented first? Otherwise we are just updating payjoin-cli to employ non-existent or non-intentional cache headers (and recommending this behavior to others).

[zealsham]

@xstoicunicornx, For now the mail-room does not support key-expiry and caching but #1449 is implementing that. We won't merge this untill key-rotation PR goes in. This PR is even older than the key-rotation one and i was updating it to fit how caching should behave from a client side if we the mail-room eventually start supporting that.

[xstoicunicornx]

Then I would likely go with @va-an 's suggestion, though maybe just return Some(expiry in unix time) instead of the cache headers.

In general I kinda consider #1449 to be a blocker of #1035 though.

[payjoin-bot]

Mshehu5

@Mshehu5

Shipped

PRs reviewed:

• forbid(unsafe_code)

Issues opened:

• Investigate whether unwrap_relay_or_else_fetch is still useful.

Last Week

Review your previous thread: Last week's thread

[Mshehu5]

Shipped :
Addressed comments and reviews in bitcoindevkit/bdk-cli#242,
Added another commit for test related to the PR

Focus :
Continue work on #1514.
Next step: open a series of smaller PRs by cherry-picking focused pieces from the larger PR so each change is easier to review.
The original PR will remain open as the “big picture” reference so reviewers can see how the smaller PRs fit together.

[payjoin-bot]

0xZaddyy

@0xZaddyy

Shipped

PRs reviewed:

• scrub: HEAD detection for colocated jj repos
• nix: crane check improvements

Last Week

Review your previous thread: Last week's thread

[0xZaddyy]

Shipped

• Add linked mailbox test for directory service. In this Poc, we tried to demonstrate that multiple parties can use deterministically linked mailboxes derived from a shared secret, with minimal changes to the directory itself. Armin helped refactor here Linked mailboxes refactor

Focus

• got some reviews from Yuval & Armin on the PR and on a call which led to a plan of working on a poc single-writer append-only mailbox and maybe creating a demo
• review PRs

Bottleneck

none

[ValeraFinebits]

Shipped

PRs opened:

• feat: Enable Payjoin v2 by default ValeraFinebits/btcpayserver-payjoin-plugin#43
• feat: Add Payjoin V2 overview page ValeraFinebits/btcpayserver-payjoin-plugin#44

PRs reviewed:

• Handle initialized Payjoin poll timeouts quietly ValeraFinebits/btcpayserver-payjoin-plugin#30
• Remove template database scaffolding ValeraFinebits/btcpayserver-payjoin-plugin#31
• Align plugin with renamed FFI bitcoin types and units ValeraFinebits/btcpayserver-payjoin-plugin#32
• Add release mode for FFI package generation ValeraFinebits/btcpayserver-payjoin-plugin#33
• Add restart replay integration coverage ValeraFinebits/btcpayserver-payjoin-plugin#34

Focus

• Continue working on the plugin.

[caarloshenriq]

/check-in

[payjoin-bot]

Shipped

PRs reviewed:

• FFI: Refactor Javascript integration test
• fix(cli): v1 config rejecting endpoints without explicit port
• Light refactor to v2 receiver for readability

[caarloshenriq]

Focus

• finish no_std implementation
• Review PRs

Bottleneck

I'm traveling, I'll be back on June 2nd.

[bc1cindy]

@bc1cindy

Shipped

Issues:

• Tracking: relay-observable behavioral fingerprinting #1586
• Add radix-based lower bound for sub-transaction mappings tx-indexer#84

PRs opened:

• (not-to-merge) kicking the tires: dense subset sum in btsim tx-indexer#86
• Add radix-ness classifier as first step of the radix lower-bound path tx-indexer#85
• Document ohttp relay best practice #1547

PR reviewed:

• Add Payjoin Receiver Support (BIP 77) lightningdevkit/ldk-node#746
• [WIP] Add AS-aware relay selection #1514
• forbid(unsafe_code) concurrent-psbt#17
• prop-tests and unit-tests feature flags concurrent-psbt#18
• Join and PartialJoin traits concurrent-psbt#20
• scrub: skip flake checks for conflicted commits concurrent-psbt#21
• scrub: report VCS errors instead of silent swallow concurrent-psbt#22
• nix: crane check improvements concurrent-psbt#23
• scrub: HEAD detection for colocated jj repos concurrent-psbt#24
• more treefmt formatters & cargo sort concurrent-psbt#27
• nix: cargo-mutants flake check concurrent-psbt#29
• scrub: some left over fixes concurrent-psbt#31

Focus

• review concurrent-psbt
• review more in payjoin
• ohttp-relay fingerprinting
• radix integration to tx-indexer

[va-an]

/check-in

[payjoin-bot]

Shipped

PRs merged:

• docs(cli): update relay url
• fix(cli): v1 config rejecting endpoints without explicit port
• docs(typo): oblivous -> oblivious

[va-an]

Focus

• RelayManager does not completely manage relays #1582

Bottleneck

• RelayManager does not completely manage relays #1582 is blocked by Split resume session relays #1399
• Awaiting comments / concept ACK from @DanGould:
  • Update "Receive Payjoin V2" tutorial to current API payjoin.org#139
  • Keep tutorial code in sync with rust-payjoin payjoin.org#140

[xstoicunicornx]

/check-in

[payjoin-bot]

Shipped

PRs merged:

• Light refactor to v2 receiver for readability
• FFI: Refactor Javascript integration test
• Add tests for OriginalPayload and PsbtContext

PRs reviewed:

• Document BIP77 v1 fallback behavior in create_post_request
• Add max_fee_rate() method to Config to encapsulate default
• Delegate http tracing to tower middleware
• Fix resume succeding prematurely
• Receiver fallback typestate

Focus

• Review Not --all-features test suite #1038
• Rename Reference and TaggedReference entities in Non-blocking Interface for Payjoin State Machine  #1446
• Organize follow up for General question on receiver's ProvisionalProposal and Monitor typestates #1548

Bottleneck

None