The MX you must not publish yet
An MX pointing at a server that does not know your domain bounces mail permanently. The ordering rule, and the DNS records the platform keeps.
The day Thursday meant Thurgau
Six locales, one of them the source language. gettext fuzzy-matched 2327 entries in it. No symptom, until a flag went missing.
Buying a domain from Django
A 1990s XML protocol, an MD5-of-MD5 signature, a DOCTYPE you must not parse naively, and calls that debit an account. What the wrapper has to get right.
The flag that was written and never read
A Stripe webhook set is_active to False and nothing on the request path read it. The middleware that fixed it, and the four exemptions it needs.
Certificates for domains that do not exist yet
Caddy issues a certificate at the first handshake for a name it has never seen. Without the right ask endpoint, that is a free certificate mint for anyone.
A DNS zone you can only write whole
SET_DNS_ZONE replaces everything. That one constraint decides where truth lives, how you delete a record, and why the mail block is published late.
Configuring django-tenants properly
Schema per tenant is the easy part. This is the configuration that decides whether your image builds, whether a Postgres blip takes the fleet down, and whether migrations run.