Third-party API
Maps, SMS, payments, AI, tax filing: services run by other companies that your product calls over the internet and usually pays for per call.
Updated October 2026 · with examples from our own builds
What does Third-party API mean in practice?
Few products build their own maps, SMS gateway or tax filing. They call a third-party API and pay per request. That buys months of work for a small fee, and it also hands part of your product's behaviour, uptime and cost to someone else.
It helps to know which calls are billed, how many each user action makes, and what the product does when the supplier is down or returns nonsense. A missing input passed to a weather or maps service can produce a confident wrong answer rather than an error, and nothing on screen looks broken.
Good practice is to keep each supplier behind one adapter in the code, log every call and its cost, and show users a clear status when an outside system fails.
Third-party API at a glance
- Billing
- Usually per request, so volume and bugs both reach the bill
- Main risks
- Outages, price changes and silent bad answers
- Design rule
- One adapter per supplier, with logs and retries
Where has Third-party API come up in our builds?
Google Maps is ₹7.45 of the ₹7.86 third-party cost of a consumer trip, while driver matching costs nothing because it runs on a MongoDB geo query and local distance maths, never on Google.
A review found that none of the nine watering call sites passed a location to the weather service, so every schedule had used a fixed 31°C, 28% humidity placeholder. One resolver now feeds every call site, and the forecast falls back in four steps with the source sent to the app.
The proposal puts each outside system behind an adapter with a request log, retries and a status users can see: a GST Suvidha Provider for e-invoices and e-way bills, Tally export, container and flight tracking, email and WhatsApp. Proposed, not built.
Common questions about Third-party API
What happens to my app when a supplier's API goes down?
That depends on the design. A good one shows a clear status, retries or queues the work and falls back where it can: LeafRanger's forecast drops from a live reading to today's forecast, then the last known reading, then unknown, and tells the app which one it used.
How do I stop a supplier's API bill from surprising me?
Log every billable call with its approximate cost, count calls per user action, and alert on the count rather than waiting for the monthly total.
Related terms
Planning a product and not sure where Third-party API fits? Ask us, or browse all 116 terms in the glossary.