REST, SOAP, GraphQL API development & integration
Webhooks, real-time event processing, queue-based systems
OAuth2.0, JWT, SSO, multi-provider authentication flows
Payment gateway integrations (Stripe, PayPal, SSLCommerz, bKash)
Third-party SaaS integrations (HubSpot, Airtable, ClickUp, Notion, Meta APIs)
Custom API creation for mobile apps, dashboards, external partners
API security hardening (rate limiting, token lifecycle, IP restrictions)
API versioning, documentation, monitoring, analytics