Start with
a question.
Something familiar, something unexpected. Find an explanation that makes you want to look closer.
Find your question ↗Complex things. Clearer pictures.
Explore the parts, follow the connections,
and see the whole thing.

From a tap at checkout to a drop of rain.
There is a whole system hiding in plain sight.

Follow a payment from checkout to confirmation—and see why “processing” is not the same as “paid”.

From a familiar address to a server: meet the lookup that gets you to the right place.

Follow water through the atmosphere, across the land, and below the surface.

Connect your pedals, chain, and wheels—and see how a gear change changes the effort.

Read the journey behind a tracking status, from a printed label to the final handoff.

Explore the decision between waiting, retrying, and a confirmed payment.

See why finding a website does not always start from scratch.
What really happens when you pay online?
Follow six steps, one connection at a time.
A customer chooses how to pay. The payment begins with an amount and a currency; collecting payment details does not mean it has succeeded.
A customer chooses how to pay. The payment begins with an amount and a currency; collecting payment details does not mean it has succeeded.
The payment is confirmed with a payment method. Confirmation asks the payment system to attempt the payment.
Some payments require an additional customer action, such as authentication. Others move on without this step.
Some methods process asynchronously. A processing state means the final outcome is still pending.
A successful payment reaches succeeded. A failed attempt may require another payment method; a cancellation is another possible outcome.
The merchant uses the verified payment result to decide what happens to the order. The illustrated success path omits retries and method-specific branches.
Give every element a role. Know what you are looking at.
Trace an action to its consequence, including the branches.
Move between one detail and the system it belongs to.
Confirmation attempts the payment. After any required action or processing, a verified successful result is the signal to fulfill the order.
Choose a question.
Take it apart. Put it together.
Something familiar, something unexpected. Find an explanation that makes you want to look closer.
Find your question ↗A domain name. A resolver. A server. Put a name to every role before following the connections.
Meet the resolver ↗A familiar name.
An address a computer can use.
See how changing one part changes another. Smaller front chainring, easier pedaling: a relationship you can use.
Follow the chain ↗
Revisit the steps, read the scope, and go to the source. A clear explanation shows you where the model ends, too.
See the whole explanation ↗
Some things need a map.
Others, a path through the possibilities.

Connect the pieces. See how a domain name, a resolver, and a server work together.
Explore this explanation ↗
Put events in order. Follow a payment from checkout to a confirmed outcome.
Explore this explanation ↗
Explore the fork in the road. Understand why a payment can need another action.
Explore this explanation ↗
Build an idea one step at a time. Follow water through a system with many paths.
Explore this explanation ↗