Assess coverage breadth, data freshness, webhook reliability, and documentation depth. Probe rate limits, pagination shapes, and historical backfill policies. Ask for real examples of corporate actions, complex option positions, and multi-currency handling. Evaluate security attestations and roadmap alignment. A strong partner reduces hidden integration taxes, ensures maintainability, and accelerates your team’s focus on differentiating product work rather than plumbing.
Clarity beats complexity. Use simple language, recognize institutions quickly, and preview what will be shared and why. Offer helpful retries, resilient progress indicators, and post-link confirmations that immediately reward success with tangible value. Thoughtful UX reduces abandonment, stabilizes conversion across mobile and desktop, and sets the tone that your app is both secure and meaningfully helpful from the first connection.