A cloud migration is one of the few enterprise IT projects where a mistake can simultaneously blow the budget and take production systems offline. Choosing the right migration partner is the single biggest lever you have to prevent that.
Every cloud migration company will tell you they can move your workloads to AWS, Azure, or Google Cloud. That is table stakes; the tooling to lift and shift a virtual machine is not the differentiator it was a decade ago. What actually separates a good migration partner from a mediocre one is judgment: knowing which workloads should be re-hosted as-is, which should be re-platformed to take advantage of managed services, and which should be left alone entirely because the cost of migrating them exceeds any plausible benefit for years to come.
We have inherited migration projects that were technically completed by a previous vendor and still cost the client more, and worked worse, than the on-premises environment they replaced. The pattern is almost always the same: a partner optimized for migration velocity rather than post-migration outcomes, moved workloads without re-architecting them, and left the client with a cloud bill that grew faster than anyone expected. Before you sign with a cloud migration company, these are the questions worth asking directly.
A competent migration partner does not default to "lift and shift" for every workload, nor do they insist on a full refactor when a simple rehost would serve you just as well. Ask them to walk through their assessment methodology in detail: how do they categorize your application portfolio, what criteria determine whether a workload is refactored versus rehosted, and how do they weigh migration cost and risk against the long-term operating cost of each approach? A vendor who cannot articulate this decision framework clearly, or who proposes the same approach for your entire estate regardless of workload characteristics, is optimizing for a fast, uniform project rather than the right outcome for each system.
It is also worth asking how they handle the workloads that genuinely should not move yet — legacy applications tightly coupled to on-premises hardware, systems awaiting a broader modernization effort, or applications with licensing terms that make cloud hosting economically unattractive. A trustworthy partner will tell you plainly when migration is not the right move for a given system, rather than migrating everything because that is what the contract was scoped to deliver.
Cloud cost overruns are the most common source of buyer's remorse after a migration, and they are almost always preventable with proper upfront modeling. Ask for a detailed total cost of ownership comparison — not a vendor-supplied estimate based on list pricing, but a model that accounts for your actual usage patterns, reserved capacity opportunities, data egress costs, and the operational overhead of managing the new environment. If a vendor's cost projection looks suspiciously clean and round, press for the underlying assumptions.
Equally important is what happens after go-live. Ask specifically whether cost optimization is included as an ongoing service or billed separately, and request examples of how the vendor has right-sized infrastructure, implemented auto-scaling, or renegotiated reserved instance commitments for past clients once real usage data was available. Migrations that stop the moment workloads are technically running in the cloud routinely leave 20 to 40% of avoidable cost on the table. This is exactly the discipline we build into every migration engagement, because a successful cutover is the beginning of the cost management relationship, not the end of it.
No migration plan survives contact with production without contingencies. Ask precisely what the rollback procedure looks like if a critical workload fails validation after cutover, how long that rollback takes, and who has the authority to trigger it. A vendor without a clear, tested rollback plan is implicitly asking you to accept the risk of an extended outage on a business-critical system.
Finally, clarify ownership during the cutover window itself. Enterprises frequently assume the migration vendor is fully accountable for production stability during the transition, only to discover contractually that responsibility was more limited than expected. Get explicit, written agreement on escalation paths, on-call coverage, and decision rights during the cutover period, and make sure key stakeholders on both sides know exactly who to call at 2 a.m. if something goes wrong. Migrations that go smoothly are rarely lucky; they are the product of a partner who planned for the scenario where things do not go according to plan.
A cloud migration is a multi-month, sometimes multi-year commitment with a vendor who will, for a period, have deep access to your production environment. Evaluate them with the same rigor you would apply to any critical infrastructure decision, and do not let a compelling timeline or price substitute for a clear answer on architecture judgment, cost discipline, and cutover risk management.