Where checkout keys belong: browser, shop backend, and payoutsA checkout integration needs credentials with different exposure rules. The browser needs enough access to open checkout; your server needs to create invoices; the process handling withdrawals needs a17h ago · 4 min readpaymos-engineering.hashnode.dev
Your webhook sender is an SSRF gadgetMost writing about webhook security is about the receiving end. Verify the signature, compare in constant time, reject a stale timestamp. All correct, all about the wrong direction for the problem I wAug 23 · 5 min readpaymos-engineering.hashnode.dev
Duplicate webhooks are the contract, not the bugA payment webhook is not a message. It is a delivery attempt. Paymos makes 11 of them per event: one initial call and ten retries, spaced 1m, 2m, 4m, 8m, 16m, 32m, 1h, 2h, 4h, and 8h, for a window of Aug 16 · 7 min readpaymos-engineering.hashnode.dev
