Mobile App Modernization Services
FISTA Solutions modernizes and rescues existing mobile apps: auditing the codebase, crash data, and store standing, fixing what is costing you users now, then either refactoring incrementally or re-platforming — with the risks of each path written down rather than asserted.
- 150+
- projects delivered
- 50+
- companies served
- 99.9%
- verified uptime
- 47%
- efficiency gains
- 12+
- countries reached
What we build
What does mobile app modernization include?
Modernization engagements begin with an audit and stabilization of the worst user-facing problems, then proceed through dependency and OS compatibility work, architectural refactoring or migration, test coverage, and a maintainable release process your team can run.
- 01
Codebase and data audit
Written assessment of code, architecture, crash and performance data, dependencies, and store standing.
Audit - 02
Stabilization
Fixing the crashes and performance problems costing users now, before any architectural work begins.
Rescue - 03
Dependency and OS compatibility
Bringing dependencies and platform targets current so the app keeps working through OS releases.
Currency - 04
Refactor or migration
Incremental re-architecture or framework migration, chosen against risk rather than preference.
Modernization - 05
Test coverage and release process
Tests and CI so future changes are safe, plus a release process your team can operate.
Sustainability
Requirements
Which requirements shape mobile app modernization?
Modernization decisions turn on evidence rather than taste: what the crash and performance data show, how much the codebase resists change, whether the platform targets are still supported, and whether a rewrite's risk is justified by the current app's actual problems.
| Requirement | Why it matters | How FISTA builds to it |
|---|---|---|
| Evidence first | Rewrite decisions are often made on feeling. | Audit with crash, performance, and store data, and a written recommendation with the risks of each path. |
| User-facing first | Users do not care about your architecture. | Stabilization of crashes and performance before architectural work, so value arrives in the first weeks. |
| Incremental safety | Big-bang rewrites frequently fail. | Strangler-style incremental migration where feasible, with the old app shipping throughout. |
| Platform currency | OS releases break unmaintained apps annually. | Dependency and target updates with regression testing, and a maintenance cadence going forward. |
| Knowledge transfer | Apps lose teams. | Documentation, tests, and working sessions so your team or the next one can maintain it. |
Where AI fits
Where does AI fit in mobile app modernization?
AI fits modernization work itself: agents run mechanical migrations across many files, generate tests to build the safety net a legacy app lacks, and document code with no living author — all behind human review and CI verification.
- 01
Automated migration
Mechanical framework and API migrations across many files, verified by tests and human review.
- 02
Test generation
Building the coverage a legacy app lacks, so later changes can be verified rather than hoped.
- 03
Code documentation
Documenting behavior and interfaces of code whose authors have long gone.
- 04
Crash triage
Grouping and prioritizing crash clusters by user impact with the stack context assembled.
Cost and timeline
How much does mobile app modernization cost, and how long does it take?
Cost is driven by codebase condition and the path chosen; timeline by store release cycles and regression risk. FISTA does not quote blind: the audit produces a written recommendation with options and estimates for each.
The audit comes first and is a small, bounded engagement. Committing to a rewrite before understanding the codebase is how modernization budgets double, so FISTA produces evidence and options before recommending a path.
Incremental usually beats rewriting. A rewrite restarts years of accumulated edge-case handling, and FISTA recommends it only when the evidence shows the existing codebase genuinely cannot be moved forward.
Send the scope you have, even if it is a paragraph. You get a written brief, an architecture sketch, and a phased estimate before any commitment.
Get a scoped quoteDelivery
How does FISTA deliver a mobile app?
FISTA delivers apps in four phases: product discovery that produces the MVP specification and clickable flows, architecture for app and backend with the store-compliance checklist, two-week builds demoed on TestFlight and Play internal tracks, and a monitored release with analytics, crash reporting, and a post-launch iteration plan.
- 1
Discover the product
User and business goals, competitive review, feature prioritization, and a written MVP specification with acceptance criteria.
OutputMVP spec, user flows, estimate
- 2
Design app and backend
Platform decision, architecture, data model, API contracts, design system, and the store-compliance checklist.
OutputArchitecture, API contracts, designs
- 3
Build in sprints
Two-week increments shipped to TestFlight and Play internal testing, with automated UI and API tests.
OutputTestable builds every sprint
- 4
Launch and iterate
Store submission, monitoring, crash and analytics dashboards, and a prioritized post-launch backlog.
OutputLive app, dashboards, roadmap
Why FISTA
Why choose FISTA Solutions for mobile app modernization?
FISTA starts with a written audit, fixes what users feel first, and recommends rewriting only when the evidence supports it. Work is contracted through a US entity with full IP assignment.
App Modernization specifics
- The engagement starts with a bounded audit producing evidence and options, not a predetermined rewrite.
- Crashes and performance problems users feel today are fixed before architectural work begins.
- Migration is incremental wherever feasible, with the app shipping throughout rather than going dark for months.
- Tests, documentation, and a runnable release process are delivered so your team can maintain the result.
How FISTA engineers
- Spec-Driven Development: every deliverable starts as a written specification with acceptance criteria, so scope is testable before it is built.
- AI-native delivery: engineers direct coding agents under review gates and evaluation harnesses, compressing build time without loosening verification.
- Official Anthropic partner, with production experience across Claude, OpenAI, Google, and open-weight models, chosen per workload rather than by default.
- One accountable delivery lead, weekly demos on your environment, and code in your repositories from week one.
What you get as a client
- 150+ projects delivered for 50+ companies across 12+ countries since 2017, with 99.9% verified uptime on systems we operate.
- A US entity (FISTA Solutions Inc., Wilmington, Delaware) for contracting, invoicing, and IP assignment, with an engineering center in Faisalabad, Pakistan for cost-efficient senior capacity.
- US business-hours overlap for standups and reviews; written decision logs so nothing depends on a meeting you missed.
- Flexible engagement: fixed-scope build, embedded forward deployed engineers, or a dedicated team that you can scale month to month.
Clear answers
What app buyers ask before they commit.
Straightforward guidance for evaluating scope, fit, and the next step.
01Should we rewrite or refactor our app?
Usually refactor. A rewrite discards years of accumulated edge-case handling and carries schedule risk. FISTA recommends a rewrite only when the audit shows the codebase genuinely cannot be moved forward safely, and states the risks either way.
02Can you take over an app built by another team?
Yes. That starts with an audit covering code, architecture, crash and performance data, dependencies, and store standing, followed by stabilization of what is hurting users now.
03Our app breaks with every OS release. Can that be fixed?
Yes, by bringing dependencies and platform targets current and establishing a maintenance cadence, so annual OS releases become routine updates rather than emergencies.
04Can you improve performance without a rewrite?
Often substantially. Profiling usually finds a small number of causes behind most user-visible slowness, and fixing those delivers value long before any architectural work.
05How long does modernization take?
The audit takes weeks; stabilization follows immediately; deeper refactoring or migration is phased so the app keeps shipping. The audit produces the plan and estimates.
Scoped in writing before you commit
Rescue the app before you rebuild it.
Bring the repository, the crash data, and the store listing. The audit returns a written assessment, options, and estimates for each path.