Multi-tenant CRM SaaS API
CRM System
ASP.NET Core 8 Clean Architecture CRM backend—HotChocolate GraphQL for contacts, leads, opportunities, and accounts, plus tenant/subscription management on SQL Server.
The challenge
Teams needed a multi-tenant CRM API foundation—identity, pipeline objects, and subscription plans—without shipping an unfinished full CRM suite or inventing a frontend that the repo does not contain. Without a coherent multi-tenant crm saas api foundation, CRM System stakeholders faced fragmented tools, slow handoffs, and limited visibility—classic failure modes Tekvers designs against.
The solution
CRM System: ASP.NET Core 8 Clean Architecture CRM backend—HotChocolate GraphQL for contacts, leads, opportunities, and accounts, plus tenant/subscription management on SQL Server. Production-shaped CRM + identity + subscription API cores without a fake frontend claim. Tekvers delivered a maintainable multi-tenant crm saas api system for CRM System using ASP.NET Core 8, HotChocolate GraphQL, EF Core, Dapper, with phased rollout, operator workflows, and documentation suited to long-term ownership.
Approach
Clean Architecture + dual data access
Domain contracts in Core; services in Application; EF + Dapper repositories in Infrastructure; HotChocolate types/queries/mutations as the API edge—filtering, sorting, and projections enabled on the GraphQL server.
Ship the CRM + SaaS cores first
End-to-end Identity, CRM pipeline (including lead qualify/convert and opportunity stage/close aggregates), and Subscription (tenants, plans, tenant users, feature gates) before expanding scaffold-only modules.
Tenant context at the host edge
`TenantContextMiddleware` resolves multi-part hostnames to `HttpContext.Items["TenantId"]`; Serilog logs to console and rolling files; Swagger is available in Development.
Deliverables
- ▸ASP.NET Core 8 Clean Architecture Web API (`net8.0`)
- ▸HotChocolate GraphQL API at `/graphql` (CRM + auth + subscription operations)
- ▸Contact, Lead, Opportunity, and Account CRUD/query/mutation surfaces via ~46 SQL stored procedures
- ▸Lead qualify/disqualify/convert and opportunity stage/close + pipeline value aggregates
- ▸JWT Bearer auth with BCrypt password hashes; user/role GraphQL mutations
- ▸Multi-tenant tenants, subscription plans, subscribe/cancel/upgrade/downgrade via EF Core
- ▸Subdomain tenant middleware and plan feature-flag helpers
- ▸Serilog structured logging and Development Swagger UI
Outcomes
- ▸Production-shaped CRM + identity + subscription API cores without a fake frontend claim
- ▸GraphQL-first contract suitable for future web/mobile clients
- ▸Clear backlog: wire Activities/Helpdesk/Sales scaffolds and Stripe DI only when ready
- ▸Documented gaps (hardcoded user id, refresh tokens, limit enforcement) for honest handoff
Impact
Organizations get a real SaaS CRM backend to extend—pipeline objects and tenancy completed—while Tekvers refuses to market scaffold entities or Stripe helpers as finished product modules.
Tech stack
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