From June 2023 to July 2024, APIContext, in partnership with tomato pay, conducted approximately eight million API test calls across 29 UK banks to assess the quality of their open banking APIs. These APIs are essential for key digital services like payment processing and transfers, and their performance is regulated by the UK’s Financial Conduct Authority (FCA), which sees open banking as a priority for keeping the UK’s financial sector globally competitive.
While API performance overall improved, it’s still not where it needs to be for the UK to continue leading open banking across the globe. The benefits of healthy APIs extend beyond cost savings; poor-performing APIs cost millions in extra engineering costs, and regulators expect to see improvements in reliability. Although the largest banks (CMA9) and traditional banks saw improvements, neobanks started to lag behind, leading to the CMA9 almost matching the challengers’ performance, a significant reversal from our last report. Smaller, traditional banks continued to show the weakest results.
Infrastructure choices also play a big role, with fintech solutions deployed on the Microsoft Azure cloud significantly underperforming compared to other cloud providers – and even to its own results from the previous year. Here is a summary of the key findings from the report.
1. Cloud providers’ variability has increased
a. All the clouds experienced a slight decline from the numbers measured in our last reports
b. Azure’s performance declines further: Azure cloud locations, especially in Northern Europe (Norway, Sweden, Finland), experienced the highest latency in 2023-2024. This marks an 80% increase in DNS lookup times compared to the previous year. Latency in Azure’s data centres regularly exceeds 2,000 milliseconds, making it a significant bottleneck for banks using Azure.
c. Amazon Web Services (AWS) and IBM dominate: AWS and IBM continue to outperform Azure and Google Cloud Platform, offering p99 times under 600 milliseconds for most bank types, making them reliable choices for hosting critical open banking APIs.
2. Bank type roles have changed slightly
a. Neobanks lead in both availability and speed: Digital-first banks like
Tide and Monzo continue to outperform traditional banks and even some CMA9 banks. With near-perfect availability (up to 100%) and fast response times, they offer a superior user experience.
b. CMA9 banks remain stable: The performance of CMA9 banks remained relatively unchanged from the previous year, with most banks offering consistent service but struggling to match the speed and agility of neobanks.
c. Traditional banks continue to lag: Traditional banks, particularly those using Azure cloud infrastructure, are far behind in terms of API performance. We saw latencies of up to 4500 milliseconds, severely affecting user experience and contributing to increased operational costs, especially when a transaction may require three to 10 individual API calls.
3. Data centre continues to matter for banking and fintech apps
a. Akamai Connected Cloud (ACC) UK and AWS UK provide best performance: The fastest locations for open banking applications were ACC UK data centre and AWS UK, with p99 times averaging around 1084 milliseconds and 1150 milliseconds respectively. These locations are ideal for hosting critical services.
b. Azure and Google laggards: Within the UK and Ireland, when applications were called from Azure locations, they were consistently among the slowest performers. Google locations also showed higher-than-expected latency, especially in Northern and Eastern Europe.
These insights reinforce the need for ongoing investment in infrastructure, cloud optimization, and continuous monitoring to ensure the UK retains its leadership beyond open banking and into open finance. Read the report here.