The verdict in three sentences
A clean API integration between your web app, your ERP and your CRM costs in 2026 between 12,000 and 35,000 USD over 4 to 8 weeks, depending on the number of synced objects and real-time vs batch mode. The price depends less on the number of APIs than on data mapping and error handling (rate limits, idempotency, retries). An iPaaS (Make, Zapier, n8n) pays off for simple flows; custom wins as soon as business logic or volume gets serious.
Cost by complexity level
Cost tracks sync complexity, not the ERP brand. Here is an order of magnitude for 2026 (Singapore agency).
| Level | Scope | Cost USD | Timeline |
|---|---|---|---|
| Simple | 1-2 objects, one-way, batch | 12,000 - 16,000 | 4 wk |
| Intermediate | 3-5 objects, bidirectional | 16,000 - 24,000 | 5-6 wk |
| Advanced | Real-time, webhooks, dedup | 24,000 - 35,000 | 6-8 wk |
| Critical | High volume, SLA, monitoring | 35,000 - 55,000 | 8-12 wk |
Add 2,000 to 5,000 USD/year of maintenance to track vendor API changes.
iPaaS vs custom: the real trade-off
Low-code middleware accelerates but caps on volume and conditional logic. Compare on full cost, subscription included.
| Criterion | iPaaS (Make/n8n) | Custom integration |
|---|---|---|
| Upfront cost | 3,000 - 11,000 USD | 12,000 - 35,000 USD |
| Subscription / year | 700 - 8,000 USD | 0 USD (own infra) |
| Volume | Up to ~50k ops/month | Unlimited |
| Complex logic | Limited | Total |
| Idempotency / retries | Basic | Fine-grained, custom |
| Fits if | Simple flows, SME | Core business, high volume |
Mini case study
Wei, IT director of a manufacturing SME in Singapore, connects his quoting web app to the ERP (accounting) and the CRM (sales). Intermediate scope: bidirectional customer + invoice sync, webhooks on quote creation. Quote: 22,000 USD, delivered in 6 weeks. Before, manual re-entry tied up 1.5 FTE re-keying 220 invoices/month; automation frees ~38,000 USD/year of admin time. Payback in 7 months, data-entry errors cut sixfold.
FAQ
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Real-time or batch, which to choose?
Batch (hourly/nightly) is enough for accounting and cheaper. Real-time (webhooks) is justified for sales experience and stock.
Why is idempotency critical?
Without it, a retry after timeout creates duplicates (double invoicing). It is the first checkpoint of a serious integration.
How do you handle API rate limits?
We set up a queue with exponential backoff and quota monitoring; it is included in the advanced pricing.
Are ERP and CRM APIs stable?
Yes, but they evolve: budget a light retainer (2,000-5,000 USD/year) to track version changes.
Can you start small?
Yes: begin with a single critical flow in batch, then add real-time once value is proven.
Let's scope your project. List your systems (ERP, CRM), the objects to sync and the flow direction, and we'll price the integration and its mode (iPaaS or custom). Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
