SMBs do not need Fortune 500 AI infrastructure. They need a practical stack combining bought tools, custom-built components, and integrations. A well-designed SMB stack costs €15,000-€50,000 in custom work, €200-€1,500/month in SaaS, and starts paying back in 3-6 months.
The three-layer model
Think of the stack as three concentric rings:
- Buy: off-the-shelf SaaS for standard functions - low cost, fast deployment.
- Build: custom software for the workflows that make your business different - your competitive edge.
- Integrate: APIs and pipelines that connect the first two layers so data flows automatically. Without this, you still have silos.
Layer 1: What to buy
These functions are well-served by existing SaaS. Do not build them:
- Accounting (Minimax, Xero, QuickBooks) - €20-€60/month
- Email and calendar (Google Workspace, Microsoft 365) - €6-€20/user
- CRM (HubSpot, Pipedrive) - €0-€50/user
- Project management (Asana, Linear, ClickUp) - €0-€15/user
- Communication (Slack, Teams) - €0-€12/user
- E-commerce (Shopify, WooCommerce) - €30-€300/month
Rule of thumb: if the function is the same for every business in your industry, buy it. If it is specific to yours, build it.
Layer 2: What to build
Custom components are where your operational edge lives. Typical SMB targets:
- Workflow engines for approvals, order processing, and rules SaaS cannot accommodate
- Business dashboards combining data from multiple sources - see from spreadsheets to BI
- AI document processing for invoices and contracts (80-90% handled automatically)
- Customer portals for self-service tracking and account management
Cost range: €5,000-€25,000 per component.
Layer 3: What to integrate
The integration layer turns separate tools into a cohesive system. Common patterns:
- E-commerce → Accounting (auto-invoicing)
- CRM → Dashboard (pipeline visibility)
- Email → Support (auto-classification and routing)
- HR tool → Onboarding workflow
Cost: €1,000-€5,000 per integration. See API integrations.
The AI layer
AI sits on top of the three layers. Practical SMB applications: document processing (€5,000-€15,000), support chatbot (€3,000-€10,000), predictive analytics (€8,000-€20,000). Start with one, prove ROI, then expand. For broader context, see AI in business: practical examples and RAG knowledge bases.
Phased rollout: months 1-2 set up SaaS and connect accounting/CRM (€2,000-€5,000); months 3-4 build the first custom tool (€8,000-€20,000); months 5-6 integrate and add one AI application (€5,000-€15,000).
Frequently asked questions
Do I need a full-time developer to maintain this? No. A retainer of €500-€1,500/month covers monitoring, small changes, and fixes. You do not need to hire until the stack grows significantly.
What if my existing tools do not talk to each other? That is the most common starting point. Phase 1 is connecting what you have via APIs before building anything new.
Is this overkill for a 10-person company? Layer 1 applies to every business. Layer 2 starts making sense at 15-20 employees. Layer 3 is valuable whenever you have more than three tools sharing data.
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