If your challenger bank is built on composable core platforms like Mambu or Temenos, this one’s for you.
Composable platforms enable API-first integration with modular services, letting you launch, adapt, and grow products quickly. That makes API health a top priority — and it shows in our State of API Reliability Report 2025 (we’ve pulled out the key fintech findings for APAC below).
In a nutshell, fintechs in APAC lead in API uptime and mean time to resolution (MTTR) compared to other markets. But what happens when an API from a third-party provider has an issue that impacts your own services?
Why do your third-party APIs matter?
As you embed more third-party APIs into your workflows, you become responsible for managing more risk. Why?
Because in the eyes of your end users, you’re still accountable for any failed or delayed payment initiated through your bank.
In the eyes of regulators, you’re expected to maintain oversight of third-party dependencies and demonstrate that critical services (like real-time payments via FPS) meet performance and reliability standards.
This level of accountability is global regulatory norm.
To meet these expectations and mitigate risk, let’s go into those API reliability insights and explore how to advance resilience — for all the APIs your services depend on.
Focus on real outcomes, not just API uptime
APAC fintechs lead in API availability with uptime sitting at 99.86%, but that still allows for over one hour of downtime each month.
If your workflow relies on a third-party API, its downtime becomes your downtime. And when a single workflow spans multiple third-party APIs, those risks multiply fast.
There are two key challenges here. First, third-party APIs can impact your own SLAs, so consistently monitoring external dependencies is important. Second, uptime alone doesn’t guarantee payment success. You need to know whether full workflows function as intended.
Each dependency introduces a potential point of failure, making it harder to deliver the reliability both users and regulators expect. Even minor issues, like gateway timeouts or delayed callbacks, can break a payment flow.
That’s why full visibility is necessary. By accurately simulating real API workflows end-to-end, you check more than individual availability. You check the end results, too.
Third-party APIs compound performance volatility risk
Fintech APIs outperform their traditional Financial Services counterparts with median response times almost twice as fast (393.8 ms vs. 816.6 ms).
The 25th and 75th percentiles (the lower and upper edges of the boxes on the boxplot below) also demonstrate that most fintech APIs not only respond faster, but perform more consistently in typical scenarios too.
However, fintech APIs show a wider max-min variation (56.1 – 4832.6 ms) compared to Financial Services (59.5 – 4763.2 ms), indicating greater volatility.
It’s essential to stabilize your own APIs first, so that third-party variability doesn’t compound the issue. Third-party APIs are less predictable because you don’t control their infrastructure, usage by others, or the network and geographic factors that impact performance.
This matters in user-facing transactions, where any spike in latency (regardless of where it originates) can disrupt the flow. Gaining insight into how each dependency behaves under real conditions helps you proactively pinpoint the weakest link in the chain.
Start by identifying and optimizing internal outliers, then extend visibility across third-party dependencies to build resilient end-to-end performance.
APAC fintechs are MTTR trailblazers: Apply it to third-party APIs
Fintechs in APAC resolve 94% of API incidents in under 5 minutes and this rapid remediation reflects strong troubleshooting processes.
To maintain resilience as API dependencies grow, that same speed and discipline must extend to third-party APIs even though your direct control over issue remediation is more limited.
End-to-end visibility of API workflows, enabled by synthetic monitoring, alerts you when third-party APIs encounter issues — and before end users feel the impact. It also equips you with actionable insights, so you can initiate more productive conversations with external providers and accelerate troubleshooting.
You’ll know exactly which step failed, under what conditions, and how it impacted the full transaction, giving you the evidence to escalate issues and reduce back-and-forth delays.
How to validate API workflows end-to-end
Synthetic API monitoring replicates real-world workflows by chaining multiple API requests together in sequence. Unlike availability checks, these monitors simulate actual transactions, passing dynamic data between steps and validating both the response and the outcome.
For example, you might:
- Authenticate via a token API
- Initiate a payment via the gateway
- Poll for transaction status
- Query the ledger for confirmation
Synthetic API monitoring allows you to check not only whether individual APIs are up, but whether entire business-critical transactions succeed.
By taking this approach, DevOps, SRE, and platform teams gain full visibility into where failures occur. You can proactively detect broken logic, missing callbacks, or timeouts from external providers, which single-step monitoring isn’t likely to catch.
As challenger banks progress their API monitoring approach, industry leaders will take these insights beyond issue detection and resolution.
They’ll use it to support a broader reliability strategy. Here’s how.
API Monitoring Maturity Framework
For challenger banks advancing their API monitoring, progress will look like this:
| Stage | What you’re doing | What that means in practice |
|---|---|---|
| 1 | Uptime checks for owned APIs | API monitoring confirms that your own APIs respond to pings. |
| 2 | Comprehensive checks for owned APIs | Monitoring gives you actionable insights into availability, performance, and functionality issues. It lets you verify fixes and helps validate MTTR improvements. |
| 3 | Comprehensive checks for full API workflows | Simulating full workflows with chained API calls across your own and third-party APIs. Insights inform monitoring optimizations and collaborative action with internal teams, reducing MTTR. |
| 4 | Insight-driven remediation with third parties | Synthetic API monitoring insights drive conversations with external providers to accelerate proactive remediation. |
| 5 | Insight-driven decisions for provider management | Monitoring insights inform decisions on external providers and how to ensure third-party accountability. |
Whether you’re building full internal visibility or starting to collaborate more closely with partners, synthetic API monitoring puts you in control of your composable core platform.
When reliability is only as strong as your weakest API dependency, visibility isn’t optional.
It’s your safety net.
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