We migrate SaaS platforms from on-premise to cloud, monolith to microservices, and legacy to modern — with zero-downtime cutovers, data integrity guarantees, and rollback plans that actually work.
SaaS Migration Specialisms — Cloud Migration, Database Migration, Zero-Downtime, Change Data Capture, Blue-Green Deployment
Migration is the only engineering discipline where a successful outcome requires you to land exactly where you started — with every record intact, every integration working, and every user unaware anything changed. There is no room for the iterative improvement cycle that characterises new product development. The legacy system set the bar, and the migrated system must meet or exceed it from the moment of cutover.
The difficulty of migration is usually not the technical work itself — it is the invisible complexity of the legacy system. Undocumented behaviour that applications have come to depend on. Data quality issues that the legacy system masked. Integrations that behave differently in production than in staging. Our migration methodology is designed to surface this complexity before cutover, not during it.
Every migration we deliver runs in parallel with the legacy system until we are confident in parity. We use change data capture to keep both systems synchronised, run comprehensive validation at every checkpoint, and maintain a rollback plan that can be executed in under thirty minutes. Our clients know that migration failure is not a possibility we plan for — it is a contingency we engineer for.
Infrastructure cost
Infrastructure costs fixed regardless of demand — scaling requires new hardware procurement
Infrastructure cost
Infrastructure scales to demand — pay for what you use, scale instantly under load
Maintenance
Manual patching and updates create unplanned maintenance windows and security exposure
Maintenance
Managed services handle patching, updates, and backups — operational overhead reduced dramatically
Disaster recovery
Disaster recovery is expensive and recovery time objectives are measured in hours
Disaster recovery
Multi-AZ deployment and automated snapshots deliver sub-minute recovery time objectives
Developer environment
Developer environment parity with production is impossible — 'works on my machine' is real
Developer environment
Infrastructure as code means every engineer runs an identical environment locally
Talent attraction
Talent attraction suffers — engineers prefer modern cloud-native tooling and workflows
Talent attraction
Modern tooling and CI/CD practices improve developer velocity and talent retention
The economics of legacy infrastructure only improve until they don't. Cloud migration is most economical when planned proactively — before a hardware refresh cycle, before a security incident, or before scaling requirements exceed what on-premise can deliver.
Seven specialist service lines, each built for a specific phase of the migration lifecycle.
We assess your current system — codebase, database, integrations, and infrastructure — and design a migration strategy that matches your risk tolerance, timeline, and budget. We document the migration approach, parallel running plan, validation criteria, and rollback procedure before any implementation begins.
We migrate databases between engines and versions — Oracle to PostgreSQL, MySQL to Aurora, SQL Server to Cloud SQL — handling schema transformation, data type mapping, stored procedure conversion, and validation. We use CDC for zero-downtime migration of active databases.
We re-establish every third-party integration on the new platform — payment gateways, identity providers, ERPs, and external APIs — testing each in staging before cutover and implementing validation checks that confirm parity with the legacy integration behaviour.
We design and provision the target cloud infrastructure using Terraform or Pulumi, including networking, security groups, load balancers, container orchestration, managed databases, and CDN configuration. Infrastructure is version-controlled and reproducible from the first deployment.
We orchestrate the cutover using blue-green deployment — the legacy system remains active until the new system is validated. DNS cutover is a single, reversible step. The rollback plan is tested in staging before production cutover and can be executed in under thirty minutes if required.
We validate migration integrity at three levels: row counts and checksums, business logic query parity, and application-level smoke testing. For financial and healthcare data we implement reconciliation reports that compare legacy and migrated totals at every validation checkpoint.
After cutover we tune the new infrastructure: query optimisation against the production workload, caching configuration based on observed access patterns, auto-scaling policy tuning, and cost optimisation. We hand over documentation covering infrastructure, runbooks, and the monitoring and alerting setup.
A structured six-stage process from free migration discovery through parallel running, cutover, and post-migration optimisation.
We review your current system — codebase, database schema, integrations, and infrastructure — and identify the migration risks and constraints. We recommend a migration approach and produce an initial effort estimate. This session is free.
We conduct a detailed assessment of the legacy system: data volume and complexity, integration inventory, dependency mapping, and data quality audit. We document every dependency that must be recreated in the new system and identify the data quality issues that must be resolved before migration.
We produce the detailed migration plan: infrastructure design, database migration approach, integration re-establishment sequence, parallel running strategy, validation criteria, and rollback procedure. The plan is reviewed and approved before any implementation work begins.
We build and test the new system alongside the legacy system, with CDC synchronising database writes between them. We run the validation suite at regular checkpoints, resolving any parity issues before cutover is scheduled.
We execute the cutover — DNS transition from legacy to new system — in a controlled window with the rollback plan confirmed working. We monitor the new system intensively in the hours following cutover and resolve any production issues immediately.
We tune the new infrastructure based on production load, optimise queries and caching, and hand over documentation covering the new architecture, runbooks, and monitoring setup. We decommission the legacy system only after the new system has operated stably for an agreed period.
We review your current system — codebase, database schema, integrations, and infrastructure — and identify the migration risks and constraints. We recommend a migration approach and produce an initial effort estimate. This session is free.
We conduct a detailed assessment of the legacy system: data volume and complexity, integration inventory, dependency mapping, and data quality audit. We document every dependency that must be recreated in the new system and identify the data quality issues that must be resolved before migration.
We produce the detailed migration plan: infrastructure design, database migration approach, integration re-establishment sequence, parallel running strategy, validation criteria, and rollback procedure. The plan is reviewed and approved before any implementation work begins.
We build and test the new system alongside the legacy system, with CDC synchronising database writes between them. We run the validation suite at regular checkpoints, resolving any parity issues before cutover is scheduled.
We execute the cutover — DNS transition from legacy to new system — in a controlled window with the rollback plan confirmed working. We monitor the new system intensively in the hours following cutover and resolve any production issues immediately.
We tune the new infrastructure based on production load, optimise queries and caching, and hand over documentation covering the new architecture, runbooks, and monitoring setup. We decommission the legacy system only after the new system has operated stably for an agreed period.
Select an industry to see how we manage SaaS migrations for your sector's specific data integrity and compliance requirements.
Financial services migrations require zero data loss, continuous audit trail integrity, and strict compliance validation at every stage of the cutover — often with regulatory notification obligations.
Financial services migrations require zero data loss, continuous audit trail integrity, and strict compliance validation at every stage of the cutover — often with regulatory notification obligations.
Healthcare platform migrations must maintain HIPAA compliance throughout, preserve clinical audit trails, and ensure zero interruption to patient-facing services during cutover.
E-commerce platform migrations must handle large product catalogues, order history, customer data, and third-party integrations with zero revenue impact during cutover.
Logistics platform migrations must maintain continuous carrier connectivity, real-time tracking data integrity, and integration with shipper and warehouse systems throughout the transition.
HR platform migrations must preserve employee data history, maintain payroll continuity, and re-establish SSO and identity provider integrations without disrupting HR operations.
Legal platform migrations require chain-of-custody documentation for all matter data, strict access control preservation, and legal hold integrity throughout the migration process.
Perimattic's work resulted in stable production systems. The team was helpful, easily accessible, and communicative through email. Their professionalism was impressive.
Quality
4.5
Schedule
5.0
Cost
5.0
Willing to Refer
4.5
DevOps Managed Services · Oct 2023 – Aug 2024
24/7 monitoring and support for production environments plus Linux server administration for a leasing automation company.
The new architecture is scalable and highly efficient, saving a lot of money in fees. Perimattic provides high-quality IT consulting and cloud development work promptly and at great value. The team remains involved from the planning stage to providing support, showing diligence and proactiveness.
Quality
5.0
Schedule
5.0
Cost
4.5
Willing to Refer
5.0
AWS Migration (Legacy → Microservices) · Nov 2018 – Ongoing
Transitioned a travel systems company's legacy server system to an AWS-based microservices architecture with ongoing maintenance.
Four structural advantages that separate risk-managed migration delivery from hoping it works.
We have delivered zero-downtime cutovers for financial, healthcare, and logistics platforms where every minute of unplanned downtime has a measurable revenue or regulatory cost. Our blue-green deployment and CDC-based synchronisation approach is the same methodology used by the world's highest-availability systems.
We treat data integrity as a non-negotiable, not a best-effort target. We run three levels of validation — row counts, business logic parity, and application smoke tests — at every checkpoint and do not proceed to cutover until all criteria are met.
Every migration we deliver includes a documented rollback plan that is tested in staging before the production cutover. We do not take the legacy system offline until the new system is confirmed working and the rollback mechanism is confirmed executable. Migration failure is a contingency we engineer for.
Cloud migration is an investment with a measurable return. We document the expected infrastructure cost reduction, operational overhead reduction, and developer velocity improvement before the migration begins, and we measure actual outcomes against those projections after cutover.
“Migration is not a project that can be retried easily. We engineer for success the first time — with parallel running, data validation, and a rollback plan that is tested, not assumed.”
SaaS migration is the process of moving a software platform from one technical environment or architecture to another — typically from on-premise infrastructure to cloud hosting, from a legacy monolithic application to a modern microservices architecture, or from one cloud provider to another. Migration projects range from lift-and-shift re-hosting, which moves the existing application to cloud infrastructure with minimal code changes, to re-platforming, which refactors the application to take advantage of managed cloud services, to re-architecture, which redesigns the application around modern patterns such as microservices and event-driven design.
Lift-and-shift, also called re-hosting, moves an existing application to cloud infrastructure with minimal changes to the application itself — you are essentially running the same software in a different data centre. It is the fastest and lowest-risk migration approach but does not capture the full economic and operational benefits of cloud-native design. Re-platforming makes targeted changes to take advantage of managed cloud services — replacing a self-managed database with RDS, or a self-managed message queue with SQS — without redesigning the application architecture. Re-architecture — the deepest migration — redesigns the application around microservices, serverless, or event-driven patterns, capturing the full cloud-native benefit but at the highest cost and risk.
Zero-downtime migration uses a pattern called blue-green or strangler fig deployment. We run the legacy system (blue) and the new system (green) in parallel, gradually shifting traffic from blue to green as confidence grows. For database migrations, we use change data capture (CDC) tools like Debezium to continuously replicate writes from the legacy database to the new one, keeping both in sync during the parallel run. When parity is confirmed, we cut DNS over to the new system in a single, reversible step. If anything goes wrong, we roll traffic back to the legacy system within minutes.
Data integrity is the most critical risk in any migration. We validate at three levels: row counts and checksums to confirm all records migrated; business logic validation to confirm that queries against the migrated data produce the same results as the legacy system; and application-level smoke tests that exercise every data path in the migrated application. For financial and healthcare data we implement reconciliation reports that compare legacy and migrated totals at every validation checkpoint. We do not declare migration complete until all validation criteria are met.
Change data capture (CDC) is a technique that monitors a database's transaction log and emits a stream of events for every insert, update, and delete. During a migration, CDC allows us to run the legacy and new databases in parallel: the legacy system continues to accept writes, and CDC replicates every change to the new database in near real-time. This means the migration window — the period of elevated risk — is a single DNS cutover rather than a lengthy data export and import that requires the system to be offline.
Third-party integrations — payment gateways, identity providers, ERPs, and external APIs — are one of the most complex aspects of migration. We map every integration before the migration begins, identify the authentication mechanism and data contract for each, and test each integration against the new system in a staging environment before cutover. For integrations that cannot be tested in staging — such as payment providers with production-only webhooks — we design a post-cutover validation plan with rollback procedures.
The primary migration risks are: data loss or corruption during transfer; integration failures when the new system behaves differently from the legacy; performance regressions if the new infrastructure is under-provisioned or not optimised; and extended downtime if the cutover does not go as planned. We mitigate these through parallel running, CDC-based synchronisation, comprehensive pre-cutover validation, load testing of the new environment, and a detailed rollback plan that can be executed in under thirty minutes if the cutover fails.
A focused lift-and-shift migration of a mid-complexity platform typically takes eight to sixteen weeks including assessment, infrastructure setup, data migration, integration testing, parallel running, and cutover. A re-platforming engagement that makes targeted changes to leverage managed cloud services typically takes twelve to twenty-four weeks. A full re-architecture — redesigning the application around microservices or event-driven patterns — is typically a six to eighteen month programme depending on the size of the codebase and team.
A lift-and-shift migration assessment and plan starts from around USD 10,000. A full lift-and-shift migration delivery — including infrastructure setup, data migration, integration testing, and cutover — typically ranges from USD 25,000 to USD 80,000 depending on complexity. Re-platforming projects range from USD 50,000 to USD 150,000. Re-architecture programmes are quoted as phased programmes. We scope every engagement before quoting.
Every migration we deliver includes a documented rollback plan that can be executed within thirty minutes of cutover. Because we use blue-green deployment with parallel running, the legacy system remains operational until the migration is validated — it is never taken offline until we are confident the new system is functioning correctly. If a critical issue is discovered post-cutover, we roll traffic back to the legacy system immediately and investigate before attempting the cutover again. We do not cut legacy systems over until validation criteria are met and the rollback mechanism is confirmed working.
Tell us about your current platform and target architecture and we will scope a migration plan with a realistic timeline, a clear validation criteria, and a rollback procedure you can trust. Free discovery call — no obligation.