Stripe webhook returns 200 on DB write failures

The code that's running in prod

# webhook_handler.py
# Receives charge.succeeded events from Stripe.

processed = set()

def handle_webhook(event, db):
    """Returns (status_code, body). Stripe retries on non-2xx."""
    if event["id"] in processed:
        return (200, "already processed")

    # Mark this event as processed so duplicate webhooks no-op.
    processed.add(event["id"])

    try:
        db.write(event["id"], event["data"])
        return (200, "OK")
    except IOError as e:
        print(f"[ERROR] write failed for {event['id']}: {e}")
        return (200, "OK")    # avoid retry storm

Log dashboard (last 60 seconds)

Pick the root cause

Four candidates. Three are plausible but mistake symptom for cause. Pick what you'd write in the postmortem timeline.