Over the past two years, I’ve been involved in dozens of negotiations with fintech companies, neobanks, and funds looking to integrate payment, custody, or trading APIs. What I’ve learned is that most API purchase decisions are not made based on polished slides or features — they happen when the client clearly sees how this API solves a specific operational task and saves resources. Sales begin where trust and business value align.
What Are B2B APIs and Why Are They Hard to Sell?
On the surface, it seems simple: APIs automate processes and reduce manual work. But when it comes to implementation, the barriers quickly become clear. As McKinsey noted back in 2023, 85% of B2B fintechs adopted APIs as part of their strategy — but even tech-savvy teams still face concerns, from lack of visible ROI to legacy infrastructure or fear of breaking something in production.
In my experience, there are three main barriers:
- Internal approval complexity (Legal, compliance, and IT teams often raise questions around architecture, data storage, and regulatory risks. In one case, a bank’s CFO demanded an independent API security audit before any technical talks could proceed);
- Lack of immediate ROI (When asked “Why do we need an API?”, we had to manually calculate the time and money spent on manual client verification. Only after quantifying the cost did the fund move forward with a pilot);
- Internal burnout (Even when teams understood the value, they just didn’t have the bandwidth. One neobank’s CTO kept postponing sandbox testing for weeks, citing endless firefighting. The solution was to bring in an external pre-sale team to offload their core engineers).
Personal Experience: 3 API Integration Cases and Sector Examples
Case 1: Central European Neobank
Faced with strict internal security policies, the client rejected standard SDKs. We provided a custom sandbox, conducted a code audit, and implemented IP whitelisting. As a result, they successfully expanded API usage across their onboarding and payment layers within four months.
Case 2: Institutional Brokerage Firm
This client struggled to integrate trading APIs due to OMS limitations and internal latency issues. A tailored load simulation helped benchmark their environment, while hands-on support enabled them to deploy a stable interface. This led to a multi-year agreement and additional API adoption in reporting.
Case 3: Fintech Fund in Emerging Market
The client required a KYB module adapted to regional regulations. Legal alignment and modular documentation helped localize the integration. Within six months, two more components were added, including real-time risk scoring and automated compliance checks.
These cases show that API sales typically begin with a sandbox, evolve through targeted support, and deepen with time through product expansion.
In parallel, sector-wide adoption is gaining traction. Payment gateways — including examples like Whitepay, CoinPayments, NOWPayments, and BitPay — are actively used by merchants and platforms across regions to handle crypto invoicing, settlement, and reconciliation. These examples reinforce the idea that successful API integration relies on both technical alignment and trust across teams.
API Infrastructure: Observations Across Leading Platforms
To better understand how the market operates, I examined the integration practices of five large-scale crypto platforms. While each has its unique architecture and documentation style, several patterns emerged:
Some prioritize REST/WebSocket interfaces for high-frequency or institutional clients, while others focus on developer experience, sandbox availability, and integration speed. A few platforms offer extensive customization and fast onboarding but operate within smaller ecosystems. Others trade flexibility for high compliance standards and robust audit trails.
For teams evaluating a platform, the most relevant indicators tend to be: onboarding time, support responsiveness, API clarity, and long-term adaptability. No platform is perfect — the key is alignment between internal architecture and external tooling.
What Works: A Framework for Successful API Sales
An important perspective also comes from Vincent Liu, CIO at Kronos Research, who shared how they internally evaluate API efficiency beyond the usual surface metrics:
“When we evaluate API integrations, we care less about vanity metrics like raw call volume and more about real impact cutting latency, reducing ops overhead, and scaling developer adoption. ROI isn’t always immediate, so we focus on KPIs like time-to-deploy, error rates, uptime, and usage growth over rolling 30-day periods. It’s all about aligning tech performance with business outcomes.”
Here’s the formula that has worked for me:
- Show value, not features. Don’t say “WebSocket API,” say “40% less manual work.” In one case, an investment app provider cut client order handling time from 6 hours a day to just 2, thanks to automatic mapping of order limits and execution statuses.
- Pre-sale + sandbox. Trust is built on a technical level. Without a dedicated sales engineer, deals often stall. In one fintech case, bringing in a pre-sale engineer by the second call helped clarify security architecture and win over a skeptical CTO. Sandbox testing with API keys fast-tracked the final contract.
- Timed upsell. Two to three months after go-live is ideal for revisiting the client with adjacent APIs. In one case, the client first integrated a payment gateway and came back proactively 8 weeks later to discuss custody APIs. Regular post-integration communication and performance insights made that conversation possible.
Conclusion
Selling B2B APIs isn’t about documentation or SLAs. It’s about solving real problems, speaking the language of multiple stakeholders, and staying involved beyond the initial sale.
If you’re selling APIs, don’t rush to highlight features. First, demonstrate what your API automates, who it helps, and how it saves money. The rest is trust, support — and timing.