A zap answered over NWC waits on far fewer round trips, and a phone with Coinos behind another app answers from its worker. "I'm on V3 … I find nwc zaps a lot more slower than usual" (398ja, 2026-11-10). Measured from the notifier's wakes and the ASP's log over four days: a closed app took about six seconds from the push to its cosign (the Lightning part after that is one and a half), an Android phone fifteen at the median, up to thirty. Where it went: every call to the ASP and the notifier was two round trips (no Access-Control-Max-Age, so Chrome re-asked the CORS preflight after five seconds; a Cloudflare response-header rule now sets 7200 on OPTIONS for ark.coinos.io, ark-staging and nwcpush), and the worker made them one after another: answered?, GetArkInfo, Handshake, claim, a save, the chain tip, then the payment, then status ("pending"), the tip again, the held status call, and status once more for the preimage it had just been handed. Now: what the mirror alone decides (invoice, network, budgets, coins, keys) comes first with no network; the claim (which now also says "already answered", coinosv3-server 3c5e9c3) goes out beside the manager's start, whose info call, handshake and tip run together (init, warmTip/_tipFresh); a send just initiated returns to its caller instead of asking at once, and awaitLnPay settles from the held call's own answer. A worker-style send on regtest: eight calls, six in sequence, where there were thirteen. The app's own answer no longer waits a second on a phone that is on screen (only one behind another app holds back for a computer).

Android freezes an app behind another one, and the worker's nudge to it sat unread until it was opened: on a phone the worker now hands a request only to a window on screen (as it already did on iOS), nudges a hidden one in case it is awake, and answers itself; the request's lock decides between them. For that the mirror is no longer written over the worker's hand: the worker stamps its writes (workerAt), the app writes under the worker's own lock (nwc-bg-work) and folds the worker's state in first (never mid-payment), carries the stamp, absorbs it when it comes back on screen (arkBgAbsorb), and refreshes the mirror as it goes behind another app.
Tests: ln-pay-double-wake (the one held call settles; a failed or mismatched answer doesn't), sw-push-quota (an Android phone's hidden window), nwc-sw-test's notifier stand-in answers /claim as the real one; tools/ark/ln-e2e-test's pay half against regtest captaind 0.8 + CLN

Co-Authored-By: Claude Fable 5.2 <[email protected]>

1 files changed, 4 insertions, 1 deletions

diff --git a/tools/nwc-sw-test.js b/tools/nwc-sw-test.js
index 7e85ee1..18528a2 100644
--- a/tools/nwc-sw-test.js
+++ b/tools/nwc-sw-test.js
@@ -58,7 +58,10 @@ function harness({ rec = baseRec(), recs = null, answered = false } = {}) {
       return { ok: true, json: async () => ({ ok: true, scheduled: true }) };
     }
     if (url.includes('/claim')) {
-      return { ok: true, json: async () => ({ ok: true }) };
+      // as the notifier does: a request already replied to can't be claimed
+      const was = typeof answered === 'function' ? answered() : answered;
+      if (JSON.parse(opts.body).release) return { ok: true, json: async () => ({ ok: true, released: true }) };
+      return { ok: true, json: async () => (was ? { ok: false, answered: true } : { ok: true }) };
     }
     if (url.includes('/answered')) {
       return { ok: true, json: async () => ({ answered: typeof answered === 'function' ? answered() : answered }) };