Calling external APIs directly feels clean... until your system hits real traffic.
When I first started integrating external APIs into my projects, my approach was simple:
Need data?
Call the API.
It felt clean, logical, and completely fine.
Until real usage hit.
The naive approach (what I did first)
The initial setup looked like this:
Client
↓
API Gateway
↓
External API
Every request triggered:
- a fresh API call
- a network round-trip
- dependency on someone else’s uptime
For low traffic, this felt clean and straightforward.
But real usage exposed the cracks very quickly.
What went wrong
1. Cost scales faster than traffic
Many APIs charge per request.
What looks cheap at first becomes expensive once background jobs, retries, and traffic spikes enter the picture.
2. Rate limits become architecture limits
Once you hit rate limits:
- features fail
- errors propagate
- defensive code spreads everywhere
Your system starts being shaped by someone else’s rules.
3. Latency adds up
Even fast external APIs are:
- network-bound
- unpredictable
- outside your control
The shift: treat APIs as data sources, not live dependencies
Instead of calling the external API on demand, I switched to this model:
Worker / Cron
↓
External API
↓
Database
Client
↓
API Gateway
↓
Backend Service
↓
Database
External APIs are called periodically.
The application reads from the database.("not the API")
What I gained
1. Predictable costs
No surprise bills. No hidden usage spikes. Just controlled API consumption.
2. Faster responses
Database reads are faster and easier to optimize.
3. Isolation from external failures
If the API goes down, my system keeps working with the last known good data.
But doesn’t data get stale?
Yes... and that’s the point.
The real question is not “Is the data fresh?”
It’s “How fresh does it need to be?”
Freshness is a business decision, not a reflex.
When direct API calls actually make sense
Since then, I’ve been much more intentional about when an external API is part of the request path and when it shouldn’t be.
That single change has simplified more architectural decisions than any framework ever did.
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