Same extensions, either architecture.
Your laptop has an ARM chip. Your servers probably do not — or they are about to, because ARM instances cost less. Either way you end up maintaining two builds of the same thing, and hoping they behave identically. That is the part we take off your plate.
x86_64
The architecture most production servers still run
What almost every hosting plan, CI runner and older on-premise machine gives you. Still the safe default, and still where most PHP applications are deployed today.
aarch64
Apple Silicon, Graviton, Ampere, Raspberry Pi
Your development machine, and increasingly the cheaper option at your cloud provider. Running it locally under emulation works, but it is slow and hides the differences that matter.
One container definition. Pick the architecture from a dropdown and rebuild — same PHP version, same extensions, same layers.
No second Dockerfile.
Cross-building PHP extensions is where multi-arch setups usually go wrong: an extension compiles on one architecture and not the other, and the workarounds pile up. We build each architecture natively, so both sides come from the same definition without a fork in your repository.
Develop where you deploy.
Running an x86 image on an ARM laptop under emulation is slow enough that people stop doing it — and then local and production drift apart. With a native image for each, your machine runs the architecture you actually want to test.
Try the switch cheaply.
Wondering whether your stack survives a move to ARM instances? Build the same definition for aarch64, pull it, run your test suite. If something does not work, you have found it in an afternoon rather than mid-migration.
One dropdown
Build it for the other architecture.
Paste your composer.lock on the start page, choose x86 or ARM, and pull the
result — no account, no build pipeline, no cross-compilation.
Which architectures are offered depends on what our build pipeline currently has ready for a given PHP version and distribution — the dropdowns on the configuration page only ever show combinations that actually exist, so you cannot pick one that has no image behind it.