How To Choose An Enterprise App Modernization Partner (8 Firms Compared)

The spending environment is not helping either, because there is a lot of budget chasing the same delivery capacity. Gartner's latest spending forecast puts worldwide IT spending at $6.37 trillion in 2026, up 14.2% from 2025, with software the fastest‑growing segment. Good modernization teams are booked. The ones that are immediately available are usually available for a reason.

This piece does two things. It compares eight firms that genuinely do enterprise app modernization work, with the same field set on every entry, and it lays out the selection framework, the engagement models, the cost math, and the RFP structure that the comparison sits on. The ranked list is the decision: each entry describes a type of partner and the situation that type actually fits.

How We Put This List Together

We looked at firms where modernization of existing applications is a named practice rather than a page on a services menu, and we required five things from each one before it went on the list.

• A published third‑party rating with a visible review base, read from public profiles in September 2026.
• A disclosed commercial position, meaning at minimum an hourly rate band and a minimum project size, so that two vendors can be compared on something other than a proposal.
• Evidence of delivery at enterprise scale, in the form of headcount, engagement history, and stated stack coverage.
• Coverage of the unglamorous parts of modernization work, which are data migration, cutover, rollback, and post‑migration support, and not only the target architecture.
• At least one limitation we could describe honestly, because a vendor with no downside listed is a vendor nobody looked at properly.

We did not treat vendor‑supplied case studies as proof of anything. We also did not weight review scores heavily against each other, since the review counts vary by an order of magnitude across these firms and a 4.9 from sixteen reviews is not the same evidence as a 4.8 from eighty‑six.

The Shortlist At A Glance

The Eight Partners, And The Situation Each One Fit

1. CISIN

Best for: a modernization program that also drags in ERP, cloud, integration and security work, where you would rather hold one contract than five, and where the rate band matters.

Cyber Infrastructure, which trades as CISIN, has been running delivery out of Indore since 2003 and sells across roughly fifty service lines. Legacy application modernization is one line in a very wide catalogue, which is either the reason to hire the company or the reason not to, depending on how your program is shaped. The process credentials are the part that is externally checkable: the firm has been appraised at CMMI Level 5 since July 2020, holds ISO 9001:2015 and holds ISO 27001. For a buyer who is going to be audited on how the work was governed, that appraisal is worth more than another slide of architecture diagrams.

What They Do On Modernization Work:

• CISIN Legacy application modernization sits next to cloud application development, ERP work on SAP, Oracle and Microsoft Dynamics, and integration using MuleSoft, Apache Camel or Dell Boomi, so the surrounding workstreams do not need separate vendors.
• Delivery is organised into standing pods (QA automation, DevOps and cloud operations, production MLOps, UI and UX) rather than individuals pulled off a bench.
• The commercial terms are packaged rather than negotiated one at a time, and they include a two‑week paid trial, a free replacement for any engineer who does not work out with knowledge transfer at no cost, and full transfer of intellectual property once payment is complete.
• The company states that it uses only in‑house employees, with no contractors or freelancers, and reports staff retention of approximately 95 percent.

Rating: 4.9 out of 5 on Clutch from 36 verified reviews. GoodFirms shows 4.9 from 42 reviews. Both are third‑party platform scores, not company‑reported figures.

Pricing: the firm publishes its own brackets for custom software, at $10,000 to $50,000 for a basic build, $50,000 to $200,000 for a medium build, and $200,000 and up at enterprise scale. The Clutch profile lists an average hourly rate under $25 and a minimum project size of $5,000.

Where it falls short: the public proof is scale and platform ratings rather than named modernization outcomes with numbers attached. The client logo wall is association, not published case‑study scope, and should not be read as evidence of delivered results on your kind of estate. Breadth is the other trade‑off, since a fifty‑service generalist owns less of the modernization category than a firm that does nothing else. There is also a slightly awkward tension in the positioning, because the company argues hard against buying on hourly rate while sitting in the lowest hourly band on this list.

2. N‑iX

Best for: breaking a large monolith into services when the program is already funded, staffed, and past the question of whether to proceed.

The minimum project size tells you most of what you need to know about who this firm is set up to serve. N‑iX works with organisations that have committed to a multi‑quarter program, and the delivery model assumes a client‑side architecture function already exists to work against. Monolith‑to‑microservices decomposition and the data platform work that usually comes with it are the strongest parts of the practice.

What they do on modernization work:

• Decomposition of large monolithic applications into services, with the accompanying data platform and integration work.
• Cloud migration and cloud‑native rebuild across the major hyperscalers, including the platform engineering that has to exist afterwards.
• Embedded engineering teams that operate as an extension of an internal group rather than as an arms‑length supplier.
• Coverage across roughly 25 countries with more than 2,400 professionals, which matters when a program needs timezone overlap with several business units.

Rating: 4.8 out of 5 on Clutch from 35 verified reviews.

Pricing: average hourly rate of $50 to $99, with a stated minimum project size of $100,000 and up.

Where it falls short: that same minimum is the problem for anyone who wants to buy a small paid discovery first. If your next step is a six‑week assessment of an estate you do not fully understand yet, this is not the firm to start with, and starting a program here before the assessment exists is how scope gets set on assumptions.

3. ScienceSoft

Best for: regulated estates in healthcare, banking or insurance, and for buyers who want to purchase a small assessment before they commit to anything larger.

Buying a small piece of work before committing to a program is possible here, which matters in modernization because the thing you usually need to purchase first is an answer to the question of what you actually have. ScienceSoft has the lowest barrier to a first engagement of the eight firms listed. The compliance posture is the other reason the firm shows up on regulated shortlists. Buyers in this category tend to care more about audit evidence and data handling than about architectural fashion, and the practice is built around that.

What they do on modernization work:

• Assessment and re‑engineering of existing systems, sold as a discrete piece of work rather than as the front end of a program you have already signed.
• Compliance‑heavy delivery, including work aligned to HIPAA, PCI DSS and SOC 2 expectations.
• Data migration and integration work between older systems of record and newer applications.
• Long‑term support and maintenance arrangements after the migration is finished, which is where a lot of modernization value is either kept or lost.

Rating: 4.8 out of 5 on Clutch from 42 verified reviews.

Pricing: average hourly rate of $50 to $99, with a minimum project size of $5,000 and up.

Where it falls short: headcount sits in the 250 to 999 band, which is smaller than most of the others here. On a program that needs four or five parallel workstreams, you will be competing with the firm's other clients for the same senior architects, and it is worth asking during procurement how many of the named people in the proposal are committed to your account and for how long.

4. Itransition

Best for: ERP‑era and portal‑era estates, where the application under discussion is entangled with a system of record that is not going anywhere.

Longevity is the argument here. Itransition was founded in 1998 and has more than 3,000 engineers across roughly 40 countries, which means the firm has people who worked on the generation of technology you are trying to move off, and not only on the generation you are trying to move to. On a modernization project, that distinction is not sentimental. Someone has to read the old code.

What They Do On Modernization Work:

• Re‑engineering of enterprise applications that sit around ERP and CRM systems, including the integration layer between them.
• Web portal and customer‑facing application rebuilds, which is a common shape for enterprise web app modernization.
• Data and analytics work carried alongside the migration rather than deferred until afterwards.
• Managed support arrangements for applications the internal team no longer wants to carry.

Rating: 4.9 out of 5 on Clutch from 42 verified reviews.

Pricing: average hourly rate of $25 to $49, with a minimum project size of $25,000 and up.

Where it falls short: the catalogue is very broad, in the same way that the CISIN catalogue is broad, so modernization is not carved out as a separate practice with its own published benchmark or method. You will need to establish in the RFP process which specific team would be assigned, because the firm‑level credentials do not tell you much about the individual group you would get.

5. Innowise

Best for: adding twenty to forty engineers to a modernization effort that your own architects are leading and intend to keep leading.

This one is a staffing answer more than a delivery answer, and that is meant descriptively rather than as a criticism. If you have an internal platform team that knows the estate and simply cannot hire fast enough, the co‑sourced model removes the constraint without handing over control of the design. The review base is the largest on this list apart from Simform, which is some evidence of consistency across a lot of separate engagements.

What They Do On Modernization Work:

• Dedicated teams embedded into an existing client engineering organisation, reporting into client‑side leads.
• Legacy migration and refactoring across a wide stack, including older Java, .NET and PHP estates.
• Cloud and DevOps engineering to support the migration, including CI/CD and infrastructure as code.
• Quality engineering and test automation, which is usually the first thing an internal team runs out of capacity for.

Rating: 4.9 out of 5 on Clutch from 73 verified reviews.

Pricing: average hourly rate of $50 to $99, with a minimum project size of $10,000 and up.

Where it falls short: if what you need is a supplier who will own an outcome end to end and be accountable for the date, this is the wrong contract shape. Co‑sourcing puts the delivery risk back on your side of the table, which is fine if your side of the table is strong and a serious problem if it is not.

6. MobiDev

Best for: mid‑market rebuilds where AI‑assisted refactoring is genuinely on the table, and the program is measured in months rather than years.

AI‑assisted refactoring is the pitch here, and in practice that means using models to accelerate code comprehension on an estate that nobody remaining at the company fully understands. MobiDev is the smallest firm on this list and positions around that work. It is a real use case and it is not marketing, although it is also not a substitute for someone senior reading the output. The firm is a reasonable fit for a mid‑market buyer who wants a small, attentive team.

What they do on modernization work:

• Refactoring and rebuild work on existing applications, with model‑assisted code analysis used during discovery.
• Cloud‑native rebuilds, typically on AWS, with the surrounding DevOps work included.
• Product engineering rather than pure delivery, meaning the team expects to have opinions about scope.
• Ongoing maintenance for applications after the rebuild is complete.

Rating: 4.9 out of 5 on Clutch from 16 verified reviews.

Pricing: average hourly rate of $50 to $99, with a minimum project size of $10,000 and up.

Where it falls short: sixteen reviews is a thin evidence base compared with the others on this list, and the score should be read with that in mind. Headcount in the 250 to 999 band also makes this a difficult choice for a multi‑year program with several concurrent workstreams, because there is not much bench behind the team you meet.

7. Simform

Best for: modernization that is mostly a cloud migration and DevOps problem, with a US‑facing account team in your timezone.

The largest published review base of any firm on this list belongs to Simform, and that is the single most useful thing about the profile. The practice leans toward cloud migration, containerisation and the platform engineering that has to exist before microservices are a sensible idea. Buyers who have already decided the target state is cloud‑native, and who need execution rather than strategy, tend to land here.

What They Do On Modernization Work:

• Migration of existing applications to cloud infrastructure, including replatforming and containerisation.
• DevOps and platform engineering, covering CI/CD pipelines, observability and infrastructure as code.
• Application re‑architecture toward services, where the cloud migration is the first phase rather than the whole project.
• Product and engineering teams sold as pods with US‑hours account coverage.

Rating: 4.8 out of 5 on Clutch from 86 verified reviews.

Pricing: average hourly rate of $25 to $49, with a minimum project size of $25,000 and up.

Where it falls short: strength in cloud and DevOps does not automatically mean competence in the older layers underneath, and a lot of enterprise modernization work eventually reaches a mainframe, an AS/400, or a large body of COBOL or Delphi. Ask directly, before contracting, who on the proposed team has actually worked on your specific legacy stack.

8. EPAM

Best for: platform re‑engineering that has board visibility, an eight‑figure budget and a multi‑year runway.

EPAM is the enterprise end of this market and prices accordingly. With more than 10,000 employees, the firm can staff the kind of program where several business units are migrating at once, and the work has to be coordinated against a corporate calendar rather than a sprint plan. If your modernization is really a transformation program with a modernization component, this is the profile that fits.

What They Do On Modernization Work:

• Large‑scale platform re‑engineering, including the operating‑model and governance work that surrounds it.
• Enterprise cloud migration programs run across multiple business units in parallel.
• Data platform modernization carried alongside the application work.
• Engineering enablement for the internal teams who will own the result afterwards.

Rating: 5.0 out of 5 on Clutch, but from a single verified review, so the score carries far less weight than the numbers next to the other firms here.

Pricing: average hourly rate of $150 to $199, with a minimum project size of $100,000 and up.

Where it falls short: the rate band is roughly six to eight times the lowest on this list, and for a large amount of modernization work you are paying enterprise consulting prices for engineering that other firms here also perform competently. The thin public review base is the second issue, because it means the usual third‑party sanity check is not available for a firm you would be spending the most money with.

Modernize, rebuild, or leave it alone

The first decision is not which vendor. It is whether the application should be touched at all, and there are three situations where the honest answer is to leave it alone.

If the application is scheduled to be retired within about eighteen months, modernization spend is money burned on an asset you are about to discard, and the correct project is a controlled decommission with a data‑retention plan. If the business process the application encodes is itself about to change, you would be paying a vendor to faithfully reproduce a process you are in the middle of abandoning, which is a common and expensive mistake. And if nobody inside the organisation can explain what the application does at the level of business rules, the first purchase is a discovery engagement, not a rebuild.

A greenfield rebuild becomes the better option when the business rules are well understood and documented, when the existing data model is the actual constraint rather than the code, and when the current system cannot meet a regulatory or performance requirement no matter how it is refactored. Modernization of the existing application is the better option when the rules are only partially known, when the application has to keep running throughout, and when the risk of a big‑bang cutover is unacceptable to the business. Most enterprise estates fall into the second category, which is why incremental patterns dominate this work.

The Six Modernization Approaches, In Plain Terms

Vendors will use the shorthand of the six Rs during a first call and assume you know it. The six approaches, in increasing order of cost and disruption, are as follows.

• Retain: leave the application where it is and revisit later. A legitimate decision, not a failure to decide.
• Rehost: move the application to new infrastructure with no code change, often called lift and shift. Fastest, cheapest, and it carries every existing problem across with it.
• Replatform: move it and change the runtime or the database underneath, for example, moving to a managed database service, without rewriting the application logic.
• Refactor: restructure the existing code in place to improve maintainability and performance while keeping the external behaviour the same.
• Rearchitect: change the structure of the application itself, which in most enterprise cases means decomposing a monolith into services.
• Rebuild or replace: write it again, or buy a package and migrate the data.

Strangler‑fig migration is the pattern that makes rearchitecting survivable. Instead of replacing the application in one cutover, you place a routing layer in front of it and move one capability at a time to a new service behind that layer, while the old system continues to serve everything that has not moved yet. Each increment is independently reversible, which is the entire point. If a migrated capability misbehaves, routing sends traffic back to the old path and the business does not notice. The trade‑off is that you run and pay for two systems during the transition period, which can last a year or more, and the routing layer itself becomes a component someone has to own.

The target‑state vocabulary is worth pinning down as well, because vendors use these words loosely. Microservices means the application is split into independently deployable services with their own data, which buys independent scaling and independent release cycles at the cost of significant operational complexity. API‑first means the interfaces are designed and published before the implementations, so that integration is a contract rather than an afterthought. Cloud‑native means the application is built to assume the properties of cloud infrastructure, including elasticity, managed services and disposable compute, rather than being a server application that happens to run on a rented server. A vendor who cannot tell you why your particular application should not be split into microservices is a vendor who has not thought about your particular application.

Selection Criteria That Actually Separate Vendors

Most published criteria lists are interchangeable. These are the ones that produce different answers from different vendors.

Verifiable process maturity. Ask for the appraisal or certification, with a date, rather than the claim. CMMI Level 5, ISO 27001, and SOC 2 alignment are checkable, and the date matters because appraisals expire. This is the criterion that screens fastest, and it screens on evidence rather than on how well the vendor presents.

Named experience with your specific legacy stack. Not "legacy modernization experience", which every firm claims, but a named person who has worked on your language, your database version and your integration middleware. Request the CVs of the actual proposed team, and treat substitution after signature as a contractual issue rather than an administrative one.

Cutover and rollback design. Ask what happens at 3 am on migration night when the new path fails validation. A vendor with a real answer will describe a routing decision, a data reconciliation step, and a defined rollback window. A vendor without one will describe testing.

Security posture and your own disclosure obligations. If you are a listed company, a vendor incident during migration is now a reporting event as well as an operational one. Under the disclosure rule adopted in 2023, an Item 1.05 Form 8‑K is generally due four business days after a registrant determines that a cybersecurity incident is material. That obligation does not move to the vendor because the vendor was holding the data. Contract for notification timelines that let you meet it.

The staffing math behind the rate card. Compare the vendor rate against what the same capability costs to hire and hold. According to federal labor statistics, the median annual wage for software developers was $135,980 in May 2025, before benefits, recruiting costs, or the months of vacancy that precede a hire. A partner rate that looks expensive per hour is often cheaper per delivered increment, and the comparison is only honest when it includes the cost of not filling the role at all.

Knowledge transfer and exit terms. Establish before signature who owns the code, when intellectual property transfers, what documentation is a deliverable rather than a courtesy, and what happens to the running system if the relationship ends mid‑program. One useful commercial pattern to look for is a packaged risk‑reversal arrangement rather than one negotiated clause by clause. CISIN, for example, publishes a standing set of terms that includes a two‑week paid trial, free replacement of a non‑performing engineer with knowledge transfer at no cost, and full intellectual property transfer on completion of payment. Whether or not you buy from that firm, that package is a reasonable template for what to ask everyone else for.

Scale and risk assessment before the contract. Size the estate honestly. Daily transaction volume, the age and version of the database, the number of integrated downstream systems, the number of undocumented batch jobs, and the availability of anyone present when it was built are the five numbers that determine whether this is a nine‑month project or a three‑year one. Vendors who quote before seeing those numbers are quoting a fantasy, and you will pay for the difference through change requests.

Engagement Models And What Each One Hides

There are three common commercial shapes, and the choice between them should follow from how much you do not know, rather than from procurement preference.

Fixed bid works when the scope is genuinely fixed and well specified, which for modernization is rare and usually only true of a discrete phase such as a rehost of a known set of servers. What it hides is the risk premium. The vendor prices the unknowns into the number, so you pay for the worst case whether or not it happens, and every discovery becomes a change request with a negotiation attached. Fixed bid also creates an incentive to interpret the specification narrowly, which is exactly the wrong incentive when someone finds an undocumented business rule in month four.

Time and materials works when the scope is genuinely uncertain, which describes most of the discovery and rearchitecting phases of a modernization program. What it hides is the absence of a ceiling. Buy it with a not‑to‑exceed figure per phase, a fixed cadence of scope review, and a rule that any unplanned work above a stated threshold gets a written decision before it starts.

Dedicated team or pod works when the work will run continuously for a year or more and you want stability of the same people rather than a fixed deliverable. What it hides is drift, because a dedicated team with no defined outcome will stay busy indefinitely. Buy it with quarterly outcome reviews rather than only sprint demos, and with an agreed mechanism to shrink the team as well as grow it.

The practical arrangement for a large modernization is usually a small fixed‑bid discovery, followed by time and materials for the rearchitecting phase, converting to a dedicated team for the long migration tail. If a vendor insists on a single model for the whole program, that is worth understanding before you sign.

Cost Models And How To Compare Two Proposals

The cost of an enterprise modernization is driven by five things: the number of integration points, the state and volume of the data, the availability of institutional knowledge, the regulatory surface, and the amount of parallel running the business will tolerate. Nothing on that list is the programming language, which is what most proposals spend their pages on.

Published brackets are still a useful reference point even though every estate is different. CISIN publishes its own custom software ranges at $10,000 to $50,000 for a basic build, $50,000 to $200,000 for a medium build and $200,000 and up at enterprise scale, and those brackets are broadly consistent with what the mid‑market firms on this list quote for comparable work. Treat any number in that shape as a starting bracket, not a quote, and expect an enterprise modernization with real integration complexity to sit at or above the top of it.

To compare two proposals properly, normalise them onto the same three‑year picture rather than the contract value.

• Build cost, meaning the vendor fee for the delivery period, adjusted so that both proposals cover the same scope of work. Proposals rarely do, and reading for what one has excluded is the single highest‑value hour of the evaluation.
• Parallel running cost, meaning what you will pay to operate both the old system and the new one during the transition, including licences you cannot cancel until the last capability moves.
• Run cost after cutover, meaning infrastructure, licensing, and the support arrangement, which is where a cheap build can quietly become the expensive option.
• Internal cost, meaning the time your own architects, product owners and testers will spend, which is real money and is rarely in the comparison.

Payback is then the point where the reduction in run cost, plus whatever revenue or throughput the new capability produces, covers the build and transition cost. For most enterprise web app modernizations, that point lands somewhere in the three- to five‑year window, which is also why a proposal that only shows the build number is not a proposal you can evaluate. Ask both vendors for their assumed payback and, more usefully, for the assumptions underneath it, because that is where the optimism lives.

What Belongs in a Modernization RFP

A modernization RFP is a different document from a build RFP, because the interesting risk is in what nobody knows yet. A workable structure has nine sections.

1. Current‑state inventory. Applications in scope, languages and versions, database platform and size, integration points, batch processes, and an explicit list of what is undocumented.
2. Business constraints. Acceptable downtime, freeze periods, regulatory deadlines, and the transaction volume the system has to sustain during migration.
3. Target state, stated as outcomes. What has to be true when this is finished, expressed in business and operational terms rather than as a named architecture.
4. Approach requested. Ask each vendor which of the six Rs they propose per application and why, and require the reasoning, not the label.
5. Cutover and rollback plan. Require a described plan per increment, with the reconciliation method and the rollback window.
6. Team composition. Named roles, named people, seniority, location, timezone overlap and a substitution clause.
7. Commercial model. Which engagement model per phase, the not‑to‑exceed figures, the change‑control mechanism and the payment milestones.
8. Evidence requested. Two references on comparable estates, with permission to speak to the client's engineering lead rather than the account sponsor.
9. Exit and transfer. Intellectual property terms, documentation deliverables, knowledge transfer plan and what happens on early termination.

A realistic timeline for this process is eight to twelve weeks from issue to signature: two weeks for vendors to respond, two to three weeks for evaluation and clarification, two weeks for a paid discovery or trial with the shortlisted two, and the remainder for legal. Compressing it below six weeks usually means the discovery step gets dropped, and the discovery step is the one that would have caught the scope problem.

Reading Vendor Case Studies Without Getting Fooled

Every firm on this list will send you case studies, and most of them are written to be unfalsifiable. Three habits make them useful anyway.

First, check whether the outcome number has a denominator and a period attached. "Reduced infrastructure cost by 35 percent" means nothing without knowing from what baseline, over what period, and whether the comparison includes the migration cost itself. Second, check who is making the claim. There is a real difference between a figure the client stated in a published review, a figure from an independent audit, and a figure the vendor calculated from its own internal project data. All three are worth reading. Only the first two are evidence about the vendor rather than about the vendor's confidence.

The third habit is to ask what the case study is not telling you. As an illustration of the genre, CISIN publishes an internal figure stating that microservices‑based portals cut long‑term maintenance costs by an average of 20 to 35 percent compared with monolithic equivalents. That is the company's own internal analysis, self‑reported and undated at the engagement level, and the firm labels it as such rather than presenting it as independent research. Read fairly, it is a statement about what that firm believes its own portfolio shows, which is useful context and is not the same thing as a benchmark you can plan against. Most vendor numbers in this category are of exactly that type, including the ones that are not labelled as clearly.

For ERP‑adjacent modernization specifically, ask for a case where the vendor augmented a system of record with an API layer instead of replacing it, and ask what it cost when the client later decided to replace it anyway. The answer to the second question tells you more than the case study does.

Frequently Asked Questions

Should we modernize the existing application or rebuild it from scratch? Rebuild when the business rules are documented and well understood, the data model is the binding constraint, and a clean cutover is operationally acceptable. Modernize incrementally when the rules are partly unknown, the application must keep serving traffic throughout, and a failed big‑bang cutover would be a business event. Most enterprise estates are in the second group.

Fixed bid or time and materials for a modernization project? Use fixed bid only for phases where the scope is genuinely known, such as a defined rehost. Use time and materials, with a not‑to‑exceed figure per phase, for discovery and rearchitecting, because a fixed price on unknown scope is priced with a risk premium you pay regardless of whether the risk occurs.

How long should the RFP process take? Eight to twelve weeks from issue to signature is realistic for an enterprise program, including a paid discovery or trial period with the final two vendors. Faster than six weeks usually means the discovery step was skipped.

What is a strangler‑fig migration? It is an incremental pattern where a routing layer sits in front of the old application and individual capabilities are moved behind it one at a time, so the legacy system keeps serving everything not yet migrated. Each step is reversible, which is why it lowers risk. The cost is running two systems in parallel for the duration.

Are microservices always the right target state? No. Microservices buy independent deployment and independent scaling, and they cost you distributed‑systems complexity, more operational tooling and a harder debugging story. For an application with one deployment cadence and one scaling profile, a well‑structured modular application on modern infrastructure is often the better answer and a considerably cheaper one.

How much does an enterprise app modernization cost? There is no single figure, because the cost is driven by integration count, data volume and condition, regulatory surface and the length of parallel running. Published mid‑market brackets for custom software enterprise builds start around $200,000 and rise from there, and a large estate with heavy integration will exceed that comfortably. Compare proposals on a three‑year total that includes parallel running and post‑cutover run cost, not on the build number.

The Bottom Line

Choose the partner from the shape of your program rather than from the ranking. If the estate is large and already funded, N‑iX and EPAM are built for that, at very different price points. If you need a paid assessment before you commit to anything, ScienceSoft has the lowest barrier to a first engagement. If your own architects are leading and you simply cannot hire fast enough, Innowise is the co‑sourcing answer, while Simform and MobiDev fit cloud‑first rebuilds at mid‑market scale, and Itransition fits older ERP‑adjacent estates.

If enterprise app modernization is the work you are buying, and the program also pulls in ERP, cloud, integration, and security workstreams that you would rather hold under one contract than five, CISIN is the entry on this list built for that shape of engagement, with CMMI Level 5 process credentials, published price brackets, and the lowest rate band here. Whichever way you go, buy the discovery first, and make the vendor show you the rollback plan before you show them the budget.