CI/CD

What it means

CI means every code change triggers an automatic build and test run. CD adds automatic deployment, first to staging and, once approved, to production.

The gain is not speed but that a defect surfaces minutes after the change, while its author still holds the context. Without automation it surfaces a week later, buried under twenty other changes.

The D in the abbreviation stands for two different things. With continuous delivery every version is ready to deploy, but a person releases it to production. With continuous deployment every change that passes the tests goes to production automatically. For systems wired into accounting software or invoicing, the first option with a manual approval step is usually the safer one.

How it works in practice

On bespoke work such as a custom CRM or an API integration it is what keeps the project maintainable. One developer can live without it; a team of three cannot.

Automatic dependency and vulnerability checks usually ride along. They cost less than penetration testing and catch most ordinary problems before they reach production.

For integrations with an accounting system, such as exporting invoices from an online store, the automated tests should include real-world cases: a credit note, an invoice in a foreign currency, several VAT rates on one document, rounding. Otherwise a fault in one of them surfaces only at the monthly close, when totals do not agree and someone has to hunt for the version that caused it.

What to watch out for

Deploying automatically without tests is worse than deploying by hand: the bug reaches customers faster. And once a team habitually clicks past red tests, those tests stop being a signal and become technical debt.

Automatic deployment needs a way back as well. If a new version corrupts data, rolling back the code is not enough; the database must be restorable too. That takes data backup before every change to the database structure, and a restore procedure that has actually been tried at least once, not just written down.