Integration
You can have at-most-once or at-least-once. Exactly-once delivery is not available over a network that can drop packets — but at-least-once plus an idempotent handler gets you the thing people actually mean.
Integration
An HMAC over the request body proves the sender holds your secret. The verification is four lines — the failures are re-serialising the body, comparing with ===, and forgetting that a valid signature never expires.
Integration
Answer 200 in under a second, write the event down, and process it later. The three failures everyone hits are slow handlers, duplicate deliveries and a 500 that silently drops the event forever.
Infrastructure
If the customer has Docker, they have the product. The build is the easy half — the rest is drawing a clear line between what you ship and what stays theirs, so support does not become the business.
Infrastructure
A named volume hides your data inside Docker, where one wrong flag deletes it and ordinary tools cannot see it. Moving Postgres to a bind mount takes about a minute — here is the order that keeps a rollback available the whole time.
Infrastructure
Caddy issues and renews certificates itself, so the entire TLS setup is a hostname. Here is the config running a site, a blog and an app on one domain — plus the certificate failure that had nothing to do with Caddy.
Infrastructure
No git remote, no scp, no keys — just a command channel. Base64 in chunks works, but two silent failures will corrupt the file first: protected /tmp writes, and a pty rewriting your bytes.
Infrastructure
A shared token in a header is the right amount of auth for a machine, not a user. The three things that make it safe: fail closed when unset, compare in constant time, and scope the token to one job.
Infrastructure
Two words of SQL turn a Postgres table into a job queue that many workers can pull from safely. Measured: 0.05s to claim past a locked row, versus 4.01s of blocking without them.