Multi-vendor projects multiply complexity. Each vendor has their own methodology, incentives, communication style.
Common configurations:
- Big SI (lead) + niche SI (Mulesoft, etc.).
- Onshore (consulting) + offshore (development).
- Two SIs in competition — sometimes a customer hires two for de-risking.
- Customer + 2-3 vendors — customer's internal team plus partners.
Critical practices:
1. Single integration manager (often the customer's PM or a dedicated coordinator). Without one, vendors point fingers when things break. The IM owns the cross-vendor handoffs and dependencies.
2. Joint working sessions. Don't ping-pong across emails; bring vendors together for live decisions. Reduces ambiguity.
3. Shared project plan. Every vendor sees the unified plan, not their own slice. Dependencies visible.
4. Shared issue/risk register. One source of truth.
5. Communication channels. Slack channel per project including all vendors; weekly cross-vendor sync; monthly steering committee with leadership.
6. Clear interface ownership. "Mulesoft team owns integration A; Salesforce team owns Salesforce side." Document what each delivers and what they expect from others.
7. Schedule alignment. Different vendors have different cadences; align sprint timing where dependencies cross.
8. Defect routing. Defect found in production: who triages first? Who fixes which? Document.
9. Joint UAT. All vendors present during UAT to address issues together.
10. Cultural sensitivity. Offshore teams may have different communication norms; create space for asynchronous handoffs without losing speed.
Common pitfalls:
- Ambiguous interface boundaries — both vendors think the other owns it; nobody builds it.
- Independent timelines — Vendor A finishes; Vendor B is 4 weeks late; project slips.
- Multiple sources of truth — different vendors have their own plans; updates don't propagate.
- Vendor finger-pointing — when issues arise, "not my fault" becomes the norm.
- Customer dependency on the lead vendor — they coordinate but also dictate; conflicts.
Senior consultant role: when you're the lead, your job is partly herding cats. When you're a niche vendor, your job is to be predictable and over-communicate so the lead doesn't worry.
The more vendors, the more important explicit governance becomes. Three vendors = exponentially more complexity than one.