The verdict in three sentences
In Miami in 2026, a custom REST API costs 20 000-60 000 USD and each connector to an existing system (payments, ERP, billing) 8 000-25 000 USD. The budget depends less on code than on the number of systems to connect and the quality of their source APIs. The most underestimated item is the run: OpenAPI documentation, monitoring and error handling often make up 20-30% of total cost over time.
Cost per integration in 2026
| Integration | Complexity | Timeline | 2026 cost (USD) |
|---|---|---|---|
| Core REST API (documented) | High | 4-8 wks | 20 000 - 60 000 |
| Payment connector (Stripe/ACH) | Medium | 2-4 wks | 10 000 - 20 000 |
| ERP connector (SAP/NetSuite) | High | 3-6 wks | 12 000 - 25 000 |
| CRM connector | Medium | 2-4 wks | 8 000 - 18 000 |
| Webhook + queue | Low-medium | 1-3 wks | 5 000 - 12 000 |
| OpenAPI docs + portal | Low | 1-2 wks | 4 000 - 10 000 |
A typical integration project combines a core API and 2-3 connectors, i.e. a total budget of 45 000-110 000 USD depending on the IT landscape.
iPaaS vs custom: which model to choose
| Criterion | iPaaS (Zapier/Make/Boomi) | Custom |
|---|---|---|
| Entry cost | Low, subscription | High, capitalised |
| Monthly subscription | 100 - 1 200 USD/mo | Run 300 - 900 USD/mo |
| High flow volume | Costly (per task) | Low marginal cost |
| Local/legacy systems | Often unsupported | Fully handled |
| Control and security | Limited | Full |
| Time to launch | Days | 6-14 weeks |
| Reversibility | Vendor-dependent | You own it |
iPaaS is ideal for standard, low-volume flows. As soon as you connect legacy systems or high transaction volumes, custom becomes more reliable and cheaper at scale.
Mini case study
Aminata, IT director of a distribution firm in Miami, must connect billing, her NetSuite ERP and Stripe/ACH collections. Custom quote: core API 30 000 USD + payment connector 15 000 + ERP connector 20 000 = 65 000 USD, over 10 weeks, with a run of 600 USD/month.
Before integration, manual re-keying of payments tied up 2 half-time staff, roughly 58 000 USD/year, with a 6% reconciliation error rate. After automation: re-keying eliminated, errors near zero, monthly close 4 days faster. The labour and error savings pay back the payment connector in well under a year, before counting the reliability gained.
FAQ
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Why does a custom API cost so much?
The price covers endpoint design, security (auth, quotas), error handling, OpenAPI documentation and testing. A poorly designed API costs far more in incidents and technical debt.
Can iPaaS be enough to save money?
Yes for simple, low-volume flows, between 100 and 1 200 USD/month. But legacy systems and high volumes eventually make custom more economical.
How much is a payment connector?
Budget 10 000-20 000 USD depending on complexity (confirmation webhooks, timeout handling, automatic reconciliation).
What budget for monitoring and run?
Between 300 and 900 USD/month for hosting, flow supervision, alerting and corrective maintenance.
How long for a full integration?
Expect 6-14 weeks for a core API and 2-3 connectors, depending on the availability and quality of the source systems' APIs.
Let's scope your project. List the systems to connect (ERP, payments, billing) and your volumes: we will scope the API and connectors. 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.
