The verdict in three sentences
A desynchronized ERP and CRM produce inconsistent data that costs sales and billing errors. A well-designed connector syncs key entities (clients, orders, stock) with explicit conflict handling and a clear source of truth. In 2026, budget 8,000 to 30,000 EUR depending on entity count, sync direction and real-time needs.
What a connector must guarantee
The core problem isn't copying data from one system to another: it's deciding what to do when the two systems diverge. If a salesperson edits a client address in the CRM while accounting corrects it in the ERP, which wins? A serious connector answers this for every field, otherwise it creates duplicates and silent overwrites.
The three pillars of a reliable connector: a source of truth defined per entity, explicit conflict handling, and idempotence (replaying a message doesn't create a duplicate). Without these three, synchronization degrades data quality instead of improving it.
Cost by sync scope
Price depends on the number of synced entities, direction (one-way or two-way) and mode (nightly batch or real time).
| Scope | Entities & mode | Project cost | Timeline |
|---|---|---|---|
| Basic | Clients, one-way, batch | 8,000-12,000 EUR | 4-6 weeks |
| Standard | + Orders, two-way | 13,000-19,000 EUR | 6-9 weeks |
| Advanced | + Stock, real time | 20,000-26,000 EUR | 9-12 weeks |
| Critical | Multi-entity, high availability | 26,000-30,000 EUR+ | 12-16 weeks |
Recurring costs: connector hosting, monitoring and maintenance, i.e. 150 to 500 EUR per month in 2026. An unmonitored connector is a risk: it can stop syncing without alert and let data diverge for days.
Real time or batch: the right trade-off
Not everything needs real time. Real time costs more to build and operate; nightly batch is often enough. The choice is made entity by entity based on criticality.
| Entity | Recommended mode | Rationale |
|---|---|---|
| Client record | Batch (nightly) | Low change frequency |
| Order | Real time | Direct logistics impact |
| Stock | Real/near-real time | Prevents overselling |
| Pricing | Batch | Planned changes |
| Invoice | Event-driven | Triggered on issuance |
Rule: reserve real time for entities where lag is costly (stock, orders). For the rest, a reliable, monitored batch offers the best cost/robustness ratio.
Mini case study
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Nadia is CIO of a 60-person distribution SME in Strasbourg. Her ERP and CRM don't communicate: salespeople see day-old stock and promise already-sold products, generating 5 to 6 cancellations a week. Kolonell builds a two-way connector: clients in nightly batch, orders and stock in near-real time via webhooks, with the ERP as the source of truth on stock. Cost: 22,000 EUR, maintenance 350 EUR/month. Result: near-elimination of overselling (from ~5/week to under one a month), around 4,500 EUR of margin saved per month and restored sales confidence. The connector pays back in a little over 4 months.
FAQ
Isn't an off-the-shelf connector enough?
Sometimes, if your systems are standard and rules simple. As soon as conflict or mapping logic becomes specific, a custom connector avoids the compromises and duplicates generic tools impose.
Does everything need real-time sync?
No. Real time is justified for stock and orders; clients and pricing are fine with nightly batch. Over-provisioning real time needlessly inflates cost and complexity.
How do you avoid duplicates?
Through idempotence and stable identity keys: each record has a shared unique identifier, and replaying a message never creates a second record. This is a non-negotiable prerequisite.
What happens if a system goes down?
A good connector queues messages and replays on recovery, without loss. Monitoring alerts immediately to prevent silent data divergence.
How long to go live?
A basic scope (clients, batch) is delivered in 4 to 6 weeks. We deploy entity by entity, starting with the least risky, to validate reliability before adding real time.
Let's scope your project. Specify your two systems, the entities to sync and your desired source of truth: we'll quote a reliable ERP-CRM connector (8,000-30,000 EUR) with conflict handling. 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.
