Teamleader

Teamleader API provides comprehensive CRM, project management, and invoicing with OAuth 2.0 authentication. Supports 110 endpoints covering contacts, companies, deals, projects, invoices, quotations, time tracking, and task management with RESTful JSON architecture.

CRM functionality includes contact and company management with custom fields support. Deals pipeline with stages and workflow management. Project management with milestones, tasks, and time tracking. Invoice and quotation generation with payment tracking and PDF download capabilities. Product catalog management with pricing and categories.

Sideloading support for retrieving related items in single requests. Pagination with meta information. Custom fields for extending data models. Document templates for branded invoicing. Work types for time tracking categorization. User and team management with department organization.

Official SDKs for JavaScript, PHP, and Python with community-supported Ruby libraries. Developer portal with OpenAPI specification. Marketplace for publishing integrations. Free trial available with paid account required. Production environment only. Ideal for SME business management, client relationship tracking, project billing, time tracking automation, and financial workflow integration.