API Integration for SMEs: Connecting Systems Without the Chaos

"Our systems don't talk to each other" - one of the most common sentences we hear from mid-size businesses. The CRM knows nothing about the ERP, the shop knows nothing about the warehouse, and in between: Excel and copy-paste.

API integration solves this - if you do it right.

Table of Contents

1. What Is an API (Simply Explained)
2. The 3 Integration Approaches
3. Which Approach for Which Problem?
4. The Most Common Integrations
5. Typical Pitfalls
6. Costs and Effort
7. Checklist: How to Proceed

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What Is an API (Simply Explained)

The Waiter Analogy

Imagine a restaurant:

• You (System A): Want to order food
• Kitchen (System B): Can make food
• Waiter (API): Takes your order and brings the food

The API is the standardised way for two systems to communicate - without you needing to know how the kitchen works.

What APIs Do Technically

Your CRM                           Your ERP
    │                                  │
    └──── "Give me customer #123" ─────┤
    │                                  │
    ├──── { name: "Smith Ltd",    ◄────┘
    │       revenue: 50000 }
    │

API Call (Request): "Give me data for customer 123" API Response: The requested data in structured format

Why APIs Matter

Without API:

• Manual data entry in every system
• Excel as "integration tool"
• Errors, duplicates, outdated data
• Hours wasted

With API:

• Automatic data exchange
• Real-time synchronisation possible
• Single source of truth
• Time for more important things

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The 3 Integration Approaches

Approach 1: iPaaS (Zapier, Make & Co.)

What is it? Integration Platform as a Service - ready-made platforms that connect systems.

Examples:

• Zapier (market leader, easiest)
• Make (formerly Integromat, more powerful)
• n8n (open source, self-hosted possible)
• Microsoft Power Automate

How it works:

Trigger: New contact in HubSpot
         ↓
Action 1: Create entry in Pipedrive
         ↓
Action 2: Add to Mailchimp list
         ↓
Action 3: Send Slack notification

Advantages:

• ✅ No programming needed
• ✅ Quick to set up (minutes to hours)
• ✅ Many pre-built connections
• ✅ Cheap to start

Disadvantages:

• ❌ Limited logic options
• ❌ Performance with large data volumes
• ❌ Costs scale with usage
• ❌ Vendor dependency

Costs:

Platform	Free	Starter	Pro
Zapier	100 tasks	€24/mo (750)	€61/mo (2k)
Make	1000 ops	€9/mo (10k)	€16/mo (40k)
n8n (Cloud)	-	€24/mo	€60/mo

Approach 2: Native Integrations

What is it? Connections built by the software vendor themselves.

Examples:

• HubSpot ↔ Salesforce (native)
• Shopify ↔ Mailchimp (native)
• Slack ↔ Google Drive (native)

How it works:

• Activate in settings menu
• Connect once (OAuth)
• Data flows automatically

Advantages:

• ✅ Supported by vendor
• ✅ Often included free
• ✅ Deep integration possible
• ✅ Little maintenance

Disadvantages:

• ❌ Only predefined functions
• ❌ Not all systems available
• ❌ Limited customisability
• ❌ Sometimes only in expensive plans

Approach 3: Custom API Integration

What is it? Tailor-made development that directly addresses APIs.

How it works:

# Example: Sync customer from CRM to ERP
customer = crm_api.get_customer(123)
erp_api.create_or_update_customer({
    "name": customer.name,
    "email": customer.email,
    "revenue": calculate_revenue(customer.orders)
})

Advantages:

• ✅ Full flexibility
• ✅ Complex logic possible
• ✅ Performance optimisable
• ✅ No dependency on third parties

Disadvantages:

• ❌ Development costs
• ❌ Maintenance effort
• ❌ Needs technical know-how
• ❌ Longer implementation time

Costs:

• Simple integration: €2,000-€5,000
• Medium complexity: €5,000-€15,000
• Complex (multiple systems): €15,000-€50,000+

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Which Approach for Which Problem?

Decision Tree

Is there a native integration?
    │
    ├─ Yes → Use native (if sufficient)
    │
    └─ No
        │
        ├─ Is there a Zapier/Make connector?
        │   │
        │   ├─ Yes → Does the logic fit?
        │   │       │
        │   │       ├─ Yes → Use iPaaS
        │   │       │
        │   │       └─ No → Check custom
        │   │
        │   └─ No → Custom development
        │
        └─ No API available?
            │
            └─ Legacy system → Check middleware/scraping

Comparison Matrix

Criterion	iPaaS	Native	Custom
Setup time	Hours	Minutes	Weeks
Cost (start)	€	€-€€	€€€
Cost (scaling)	€€€	€-€€	€
Flexibility	Medium	Low	High
Maintenance	Low	None	Medium
Performance	Medium	High	High
Complex logic	Limited	No	Yes

Typical Scenarios

Scenario 1: CRM ↔ Email Marketing

• Solution: Native (usually available) or Zapier
• Effort: 1-4 hours
• Cost: €0-€50/month

Scenario 2: Shop ↔ ERP (Orders)

• Solution: Native (if available) or Custom
• Effort: 1-4 weeks
• Cost: €5,000-€20,000 (one-time)

Scenario 3: Keep Multiple Systems in Sync

• Solution: Custom (hub architecture)
• Effort: 2-6 months
• Cost: €30,000-€100,000

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The Most Common Integrations

1. CRM ↔ Email Marketing

Use Case: Automatically add contacts to newsletter lists.

Typical Flow:

New lead in CRM
    ↓
Segment assignment (by criteria)
    ↓
Add to appropriate email list
    ↓
Start welcome sequence

Recommendation: Native or Zapier

2. Shop ↔ Warehouse/ERP

Use Case: Automatically report orders to warehouse, sync inventory.

Typical Flow:

New order in shop
    ↓
Create order in ERP
    ↓
Reserve inventory
    ↓
Update shop availability
    ↓
On shipment: Tracking info to shop

Recommendation: Custom (too critical for Zapier)

3. Website Forms ↔ CRM

Use Case: Leads automatically to CRM.

Typical Flow:

Form submitted
    ↓
Create lead in CRM
    ↓
Calculate lead score
    ↓
Notify sales

Recommendation: Zapier/Make (perfect use case)

4. Accounting ↔ Bank

Use Case: Automatically import transactions.

Typical Flow:

New bank transaction
    ↓
Automatic matching with invoices
    ↓
Create booking suggestion
    ↓
Mark for review

Recommendation: Native (most accounting software has this)

5. Helpdesk ↔ CRM

Use Case: Enrich support tickets with customer context.

Typical Flow:

New ticket
    ↓
Identify customer in CRM
    ↓
Display customer history
    ↓
On escalation: Inform account manager

Recommendation: Native (Zendesk ↔ Salesforce) or Zapier

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Typical Pitfalls

Pitfall 1: Duplicates

The Problem: System A creates customer. System B creates same customer. Now you have them twice.

The Solution:

• Use unique IDs (not name/email)
• "Upsert" logic (update if exists, insert if not)
• Define master system (single source of truth)

Pitfall 2: Data Conflicts

The Problem: Customer data is changed in both systems. Who wins?

The Solution:

• Clear rules: "CRM is master for contact data"
• Compare timestamps (newest wins)
• Or: Bidirectional sync only for certain fields

Pitfall 3: API Rate Limits

The Problem: Too many requests → API blocks.

Typical Limits:

System	Limit
HubSpot	100/10 sec
Shopify	2/sec
Salesforce	100k/day

The Solution:

• Batch processing (multiple records per call)
• Queues and retry logic
• Sync during low-traffic times

Pitfall 4: Missing Error Handling

The Problem: Integration works - until it doesn't. And nobody notices.

The Solution:

• Set up monitoring
• Alerts on errors (Slack, email)
• Regular check of sync status
• Logging for debugging

Pitfall 5: Over-complicated Architecture

The Problem: Every system connected to every other = maintenance hell.

Bad:
CRM ←→ ERP
 ↕      ↕
Shop ←→ Marketing
 ↕
Warehouse

The Solution: Hub-and-spoke architecture:

Better:
         CRM
          ↕
ERP ←→ [HUB] ←→ Marketing
          ↕
        Shop
          ↕
      Warehouse

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Costs and Effort

Cost Overview by Approach

iPaaS (Zapier/Make):

Complexity	Setup	Monthly
Simple (2 systems)	€0-€500	€20-€100
Medium (3-5 systems)	€500-€2,000	€100-€300
Complex (many systems)	€2,000-€5,000	€300-€1,000

Custom Development:

Complexity	One-time	Maintenance/Year
Simple	€3,000-€8,000	€1,000-€2,000
Medium	€8,000-€25,000	€3,000-€5,000
Complex	€25,000-€80,000	€5,000-€15,000

ROI Example

Starting Situation:

• Manual data transfer: 2h/day
• Employee cost: €30/h
• Error rate: 5% → €500/month correction effort

Manual Costs:

• 2h × €30 × 22 days = €1,320/month
• Plus error correction: €500/month
• Total: €1,820/month

Costs with Integration:

• Setup (custom): €15,000 (one-time)
• Maintenance: €300/month

Break-Even: 10 months Savings after 3 years: €50,000+

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Checklist: How to Proceed

Phase 1: Inventory

• List all systems
• Document data flows (who needs what from whom?)
• Identify manual processes
• Prioritise pain points

Phase 2: Solution Selection

• Check native integrations
• Evaluate iPaaS options
• Get custom effort estimate
• Compare costs over 3 years

Phase 3: Implementation

• Start with one use case (not everything at once)
• Use test environment
• Build in error handling
• Set up monitoring

Phase 4: Operations

• Create documentation
• Clarify responsibilities
• Plan regular reviews
• Prepare for scaling

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Conclusion

API integration isn't rocket science - but it's not automatic either. The right strategy:

1. Start simple: Zapier/Make for first automations
2. Use native: If available and sufficient
3. Invest in custom: For business-critical processes
4. Think long-term: Hub architecture instead of spaghetti

The biggest mistake? Waiting too long and continuing to work manually.

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Next Steps

Want to finally connect your systems sensibly?

At Balane Tech, we analyse your system landscape and find the right integration strategy - whether Zapier, custom, or hybrid. Free consultation