Webhook lifecycle: GET hub.challenge handshake (constant-time verify-token
compare); POST verifies X-Hub-Signature-256 over the RAW body before any
parse, Zod-parses the envelope, persists inbound rows (partial-unique wamid
= dedupe against Meta's up-to-7-day redelivery), acks 200 fast and defers
media processing via the after() idiom. Rejected and rate-limited content
always acks 200 and lands as skipped/error rows, never a retryable status.
Linking: the settings panel (Installningar -> WhatsApp) mints AC- one-time
codes (sha256 stored, 10 min TTL, single use, ambiguity-free alphabet); the
webhook consumes the code, binds phone to user (HMAC-peppered hash + AES-256-
GCM at rest) and confirms with M3. Keyword commands stopp/start/hjalp;
unknown senders get one throttled M1 greeting (1/h, 3/day) behind the
sender-quota RPC, with no media download and no content persistence.
Intake worker: atomic claim on the message row (the durable job record),
company resolution (default -> sole membership -> M6 fallback, no item),
per-company inbox quota (ack-and-drop, M17 once per 10 min per sender),
MIME allowlist, 10 MB stream-checked media download, exact sha256 duplicate
check, then the shared uploadAndExtract funnel (source 'whatsapp',
channel_context caption, whatsapp_message_id) and the M4 ack with extracted
merchant/total/date. Failures wrap to 'error' + error_message + one M18.
uploadAndExtract widened: source 'whatsapp', optional channelMeta + actorId;
email/upload paths behaviorally unchanged.
Deferred to PR4: burst debounce + combined ack (M5), in-chat company choice
(M6 buttons + 8h pin), clarifying questions M7-M10, interpret-answer LLM
call, sweep cron, retention cron.
Co-authored-by: Jakob Wennberg <jakob.wennberg@gmail.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Jakob Wennberg
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