A solid cloud migration checklist covers seven stages: assessing current infrastructure, choosing a migration strategy, selecting the right provider, planning data migration and security, running a pilot, migrating in phases, and validating and optimizing after cutover. Skipping the early stages to move faster is the single most common reason migrations run over budget or cause unplanned downtime.

Cloud migration gets talked about like a single event, “we moved to the cloud,” when in practice it’s a multi-stage project with real risk at nearly every stage if it’s rushed. Businesses that treat it as a checklist to work through deliberately consistently have smoother migrations than those that treat it as a weekend project, and the difference between those two outcomes usually traces back to which stages got skipped under time pressure rather than any fundamental technical difficulty. This guide walks through that checklist in the order that actually reduces risk, as part of the same DevOps and cloud solutions planning that should underpin any migration from the start.

What Is Cloud Migration?

Cloud migration is the process of moving applications, data, and infrastructure from on-premises servers, or from one cloud environment to another, into a cloud provider’s infrastructure. It covers everything from a simple lift-and-shift of an existing server to a full rearchitecture of an application to take advantage of cloud-native capabilities, and the right approach depends heavily on what’s actually being moved and why.

Why Growing Businesses Need a Structured Cloud Migration Checklist

A business outgrowing on-premises infrastructure, or moving off an aging hosting setup, faces real stakes if migration goes wrong: extended downtime, data loss, or a bill that turns out far higher than the on-premises costs it was meant to replace. According to AWS’s own Cloud Adoption Framework, organizations that migrate to AWS following structured benchmarking practices see meaningful gains, roughly a 27 percent reduction in cost per user and a 57 percent decrease in downtime compared to less structured approaches, numbers worth taking with the understanding that they come from AWS’s own published benchmarking, but directionally consistent with what a disciplined, checklist-driven migration should produce versus an ad hoc one.

The businesses that struggle most with migration aren’t usually the ones facing genuinely difficult technical challenges, they’re the ones that treated a multi-stage project as if it were a single weekend task, skipping the assessment and planning stages entirely in favor of getting started as fast as possible. That instinct is understandable, migration projects often get greenlit under real time pressure, a lease ending, a contract expiring, a system that’s already failing, but the stages that feel like they’re slowing things down are exactly the ones that prevent the expensive problems a rushed migration tends to create.

The 6 R’s of Cloud Migration Strategy

Before touching infrastructure, every application being migrated needs a strategy decision, and the industry-standard framework for this, detailed in AWS’s official guide to cloud migration strategy and now widely used across the industry regardless of which provider is chosen, breaks down into six approaches.

Most real migrations use a mix of these across an application portfolio rather than applying one strategy uniformly, a legacy internal tool might get rehosted quickly while a customer-facing application gets refactored properly, and a genuinely obsolete system gets retired rather than migrated at all.

The Cloud Migration Checklist: Step by Step

Step 1: Assess Current Infrastructure and Readiness

Inventory every application, dependency, and data source that might be affected, along with their current performance baselines, so you have something concrete to compare against once migration is complete.

Step 2: Choose a Migration Strategy for Each Workload

Apply the 6R framework above to each application individually rather than deciding on a single approach for the entire migration, since different applications genuinely warrant different strategies.

Step 3: Select the Right Cloud Provider

Evaluate providers against your specific workload needs, existing team expertise, and budget, rather than defaulting to whichever provider is most talked about, the same evaluation covered in more depth in our comparison of major cloud providers.

Step 4: Plan Data Migration and Security

Map out how data will move, in what order, with what validation steps, and ensure encryption and access controls are configured before any data actually transfers, not added afterward as a follow-up task.

Step 5: Run a Pilot Migration

Migrate a single, lower-risk application first to validate the process end to end, surfacing problems with a contained blast radius before committing the rest of the portfolio to the same approach.

Step 6: Migrate Remaining Workloads in Phases

Move applications in planned batches rather than all at once, prioritizing by risk and dependency, so any issue that surfaces affects a limited, manageable slice of the business rather than everything simultaneously.

Step 7: Validate, Optimize, and Decommission Legacy Systems

Confirm each migrated application performs at or above its pre-migration baseline, rightsize resources based on real post-migration usage data, and only decommission legacy infrastructure once the new environment has proven stable over a real operating period, not immediately after cutover.

Communicating the Migration to Your Team

A cloud migration checklist focused purely on technical steps misses a real, practical risk: a migration that surprises end users or internal teams creates its own kind of damage, regardless of how technically smooth the underlying process was. Employees who show up to find a familiar internal tool behaving differently, or slower, without warning tend to lose confidence in the migration even if the change was ultimately an improvement. A brief, honest communication plan, what’s changing, when, and who to contact if something breaks, costs very little to put together and meaningfully reduces the support burden and internal friction during the cutover window. This matters more for customer-facing applications specifically, where an unannounced maintenance window or unexpected behavior change can visibly affect people outside the organization, not just internal staff who have more context and patience for a planned transition.

Common Cloud Migration Risks and How to Avoid Them

Downtime During Cutover

Minimizing downtime starts with the phased approach covered above, moving in planned batches with a clear rollback plan for each phase rather than a single high-risk cutover event where any problem affects the entire business at once.

Data Loss or Corruption

Data integrity validation, checksums, record counts, and spot-checks comparing source and destination, should be a required step before any legacy system is decommissioned, not an assumption that the migration tooling handled it correctly.

Unexpected Cost Overruns

Rightsizing After Migration

A workload migrated as-is from on-premises hardware is frequently over-provisioned in the cloud, since on-premises sizing decisions were often made years earlier under very different constraints than cloud infrastructure actually requires.

Avoiding Lift-and-Shift Cost Traps

Rehosting quickly is often the right first move for speed, but treating it as the final state rather than a starting point is where cost overruns tend to originate, since the infrastructure was never actually re-evaluated for its new environment. Microsoft’s Azure Cloud Adoption Framework makes a similar point regardless of which provider you’re evaluating, framing cost optimization as an ongoing operational methodology rather than a one-time step during the migration itself.

Example: An Over-Provisioned Rehosted Server

A server rehosted with the same CPU and memory allocation it had on-premises, without ever being rightsized against actual cloud usage metrics, can end up costing meaningfully more than necessary indefinitely, exactly the kind of gap a dedicated post-migration cost review is meant to catch before it becomes a recurring, unnoticed expense.

Common Mistakes Businesses Make During Cloud Migration

Businesses frequently skip the assessment stage entirely, migrating without a clear inventory of dependencies, which surfaces as unexpected breakage when an overlooked integration or data dependency turns out to matter more than anyone remembered. Security gets treated as a post-migration task rather than something configured from the first data transfer, leaving a window where data sits in a less protected state than either the original on-premises environment or the final intended cloud configuration.

Many organizations also underestimate the security implications of a migration specifically, access controls and encryption that were correctly configured on-premises don’t automatically carry over to a new cloud environment and need to be deliberately rebuilt, not assumed. And a large share of migrations skip the pilot stage entirely, going straight to a full-portfolio migration, which means the first real problem encountered affects everything at once rather than a single, contained application. A related mistake is applying the same migration strategy uniformly across an entire application portfolio, treating every workload as if it warrants the same approach, when in reality a mix of rehosting, refactoring, and retiring across different applications almost always produces a better outcome than forcing one strategy to fit everything.

How The Apps Developers Approaches Cloud Migration

Every migration we plan starts with the assessment and strategy stages covered above, treated as real project phases rather than steps to rush past, as part of the same API and backend development discipline that shapes how we handle any infrastructure-dependent project.

This connects directly to how we think about web app architecture more broadly, since an application built with reasonable portability in mind from the start is considerably easier and less risky to migrate later than one deeply tangled with a single environment’s specific configuration, a principle worth keeping in mind even for businesses not currently planning a migration.

This is the same portability discipline covered in our SaaS web app architecture guide, where avoiding unnecessary dependence on any single provider’s specific, non-portable services is one of the clearer ways to keep a future migration cheap and low-risk rather than a major rearchitecture project.

If your business is evaluating a cloud migration, or one already in progress feels riskier or more expensive than expected, that’s worth a direct conversation. You’re welcome to talk to our team about what a properly planned migration would look like for your specific infrastructure.

Frequently Asked Questions