How to Build a Clean Architecture SaaS in .NET 8 (with Multi-Tenancy & Docker)

Whenever starting a new SaaS in .NET 8, developers often waste dozens of hours rewiring the exact same baseline plumbing before building core business features.

Here is a breakdown of the production architecture patterns needed to get a scalable boilerplate running.

Whenever starting a new SaaS in .NET 8, developers often waste dozens of hours rewiring the exact same baseline plumbing before building core business features.

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techlock.dev

Here is a breakdown of the production architecture patterns needed to get a scalable boilerplate running.

1. Clean Architecture Separation

Keep domain rules isolated from frameworks:

• Core Layer: Pure domain entities (Tenant, User) and interfaces. No external dependencies.
• Infrastructure Layer: Database context (AppDbContext), token generation, and third-party integrations (Stripe, Dodo Payments, OpenAI).
• API Layer: Controllers, Swagger configurations, and dependency injection pipelines.

2. Multi-Tenancy via EF Core Query Filters

Avoid leaking tenant data across requests. Configure automated query filtering inside your DbContext:

csharp
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    // Automatically applies to all queries for entities implementing ITenantEntity
    modelBuilder.Entity<CustomerRecord>()
        .HasQueryFilter(e => e.TenantId == _currentTenantService.TenantId);
}

3. Webhook Cryptographic Verification

Never trust unverified payloads from payment gateways. Always verify request signatures using constant-time HMAC-SHA256 comparison to prevent replay and timing attacks.

4. Command Local Containerization

Ship a clean ⁠docker-compose.yml⁠ that provisions PostgreSQL, applies Entity Framework migrations, and runs your API locally in seconds.
I packaged this exact structure into a ready-to-run template called TechLock: [https://techlock.dev]
What tenant isolation strategies do you prefer in EF Core? Would love your feedback in the comments!