Let’s be honest. We have all passed the stage where «make on React» meant just assembling a beautiful SPA with order form. Now everything is different. Any serious project has the same set of problems: how to prevent a browser from collapsing with 100k+ lines with twenty columns in each? How to organize instant search and filtering on these data without eight-second lags? How do you finally make a custom feature like online editing or drag-n’drop lines not turn into a month-long marathon of rewrite optimization?
If you are reading this material, you surely already know this pain on your skin. Your software development is beyond the standard tables of antd or mui. You need real «monsters» to work with data – AG Grid, Tanstack Table, complex links with D3.js for visualization. And most importantly, you need a team that does not think about components, but about data flows and performance.
The problem is that 90% of the studios in the portfolio will show you stylish landings and corporate sites. But when it comes to high-load enterprise-grids, real-time management panels or complex B2B systems, their expertise ends with the words «we use Redux». This is no longer about frontend, it’s about architecture, about the ability to work with Web Workers, virtualization, effective caching and deep integration with backend.
That’s why we didn’t just put together another list of outsourcing React developers. We seeded the market through a sieve of specific, hard criteria focused solely on complex data tasks. We were looking for those who are not afraid of the words «million records», «competitive access» and «nano-optimization». In this shortlist are companies that have proven they can not draw an interface, but implement a complex data-intensive logic on which your company’s business processes depend directly.
How we looked for a needle in the data stack: our selection principles
Hello, colleagues. Make another list of the first companies React with beautiful sites – not our method. When it comes to choosing a partner for complex enterprise data solutions on React, the stakes are too high: performance, security and ultimately the reputation of your product.
So we approached this shortlist as a real technical investigation. We didn’t just Google and read the brochures. We have been working hard on how to objectively evaluate the expertise that companies demonstrate in words.
Here are the three whales on which our selection was based:
1. Depth, not portfolio width.
We were not interested in the number of «tacky» online shops. We purposely searched in the cases for references to work with complex data: customized admin panels, real-time analytics systems, trading dashboards, complex CRMs with thousands of entities. The key words for us were: AG-Grid, Tanstack Table, D3.js, WebSocket, real-time updates, large datasets, data visualization. If in the projects of the company this was – it got into shortlist.
2. «Social evidence» and reputation.
Reviews on Clutch and GoodFirms – it’s good, but we dug deeper. We looked:
- Who did they really work for? Mentioning well-known development enterprise brands in the FinTech, HealthTech or Logistics niche is a big plus.
- What do the reviews of former clients say? We did not search for general phrases, but for specifics: «solved the problem with productivity when loading 100k+ rows», «integrated the custom filters into the grid», «helped to optimize the rendering». This speaks of real, not declarative, expertise.
- Technical blog and Open-Source contribution. A company that thinks by categories of industry, shares knowledge. We gave preference to those who write about React optimization, work with virtualization or share cases by customizing libraries.
3. Technological shell and code culture.
React is just the beginning. We looked at related technologies in the company’s shell that are critical for working with data:
- State Management: Use of modern Redux Toolkit, MobX, Zustand instead of outdated approaches.
- TypeScript: Not an option, but a must-have for any serious enterprise React project. We considered its use to be a strict requirement.
- Backend expertise: It is important to understand that a company can not only draw an interface, but also skillfully design API-contract with backend for efficient paining, data streaming and caching (knowledge of React Query, Apollo GraphQL, SWR – big plus).
In the end, our list is not a random set of names. It is the result of a multi-step filter that dozens of applicants have passed through. We rejected those who speak in common phrases, and left those who can prove their level of case and complicated, non-trivial cases.
11 data companies: From Talented Performers To Strategic Leaders
1. Celadonsoft
This is our favorite and, according to many in the industry, the hidden champion for complex data grids. Unlike giants like EPAM, the Celadon React experts don’t spray. They focus on one thing: creating high-performance, intuitive and insanely complex React interfaces for the B2B sector. They are not just coders – they are partners who dive deep into your subject area.
Their technical stack is impressive: they virtuously own AG-Grid and Tanstack Table, customizing them to exotic requirements, fight for performance with React Query and virtualization, and know how to correctly place the most complex business logic on the client. In their portfolio – customized CRM for finance with thousands of fields, real-time dashboards for trading platforms and analytical systems where the data is not just shown but can be operated flexibly.
They do not take the scale, but the depth of dive and expertise in this very narrow area. You get not a contractor, but an extension of your team – senior developers who think like architects and understand that behind every line in the grid is a specific business operation. This is the rare case where quality, approach and technological depth put a company above more established names.
2. ScienceSoft
ScienceSoft has a key advantage – a powerful data science unit. So their approach to interfaces is different: they think not as cells, but as insiders. They don’t just draw you a table, but embed predictive analytics, anomaly detection algorithms or script analysis tools directly on the client. It’s not just a display of data anymore, it’s the intelligence layer on top of it. Ideal for products where data is not an auxiliary tool, but a main product.
3. Innovyts
These guys are obsessed with performance. While others sell chips, they sell 60 FPS on a table with a million lines. If your application starts to slow down, as soon as the user adds a fifth filter column and the scroll turns into a slide show – call Innovyts. They perform a deep code audit, maximize virtualization, Web Workers and optimize each operation. It’s pure engineering, solving problems, not creating them.
4. EPAM Systems
EPAM is an aircraft carrier in the outsourcing market. They can do anything. Do you need to design a data lake from scratch, write microservices on it, scale everything on Kubernetes and then attach to this all super-complicated React frontend with data visualization? They will do this with their internal teams, without using external contractors. It is the choice for the largest and most complex projects, where the single management and full control over all stages is more important than the flexibility and speed of a small player.
5. Toptal
Toptal is not a company in the classical sense. It is an elite exchange where you can hire a real «rockstar» from the development. Do you need someone who will write in two weeks a custom filter plugin for AG-Grid that your team couldn’t handle? Or guru D3.js for the most complex visualization? Here you will find it. This is expensive and not suitable for a full-fledged project, but ideal for solving a specific complex technical problem by one super-special.
6. Sirin Software
If your data doesn’t come from PostgreSQL, but from machine-tool sensors in the factory, medical equipment or trackers – you don’t just need a React developer, but an engineer with an understanding of hardware. This is where Sirin Software is strong. They specialize in interfaces for IoT, embedded and medicine, where data is not an API request but a constant flow with which you need to work in a special way. Their portfolio is proof that they can make the browser talk on low-level protocols.
7. Intellectsoft
Intellectsoft are the guys who come to the office to the top managers from Fortune 500 and speak with them in the same language – the language of business metrics, KPI and compliance. Their technical expertise in React is only a tool for solving global business challenges in the field of engineering, healthcare or telecom. They will build you not just a grid, but an entire ecosystem that meets all industry standards and regulations. You are not paying for a line of code, but for the certainty that you will not be fined.
8. BairesDev
BairesDev is, in fact, a huge reservoir of pre-vetted senior engineers. Their main value is the moment when your project, written in React, suddenly takes off and you need to quickly scale-triple the team. Need an expert to optimize huge lists? Senior DevOps under your infrastructure? Architect? They will find them quickly and without your involvement. This is a talent factory that solves the problem of shortage of hands, not an agency with unique creative handwriting.
9. Innovecs
These guys understand that data is not just numbers in a table. Especially in their niche – AdTech, Gaming and Logistics. They specialize in turning dry metrics into interactive, almost gaming dashboards that are enjoyable to work with for 8 hours a day. If you need to not just paint AG-Grid, but make it show real-time RTB auctions or track eSports matches – Innovecs has real and quite cool experience in building such high-load and engaging interfaces.
10. Iflexion
Iflexion – classic «heavy weights» outsourcing. They will not shock you using ultra-hot-new libraries, but will bring the project exactly on time and with respect to all T3. Their highlight is the integration of your gorgeous new React-grid with a Java-based legacy system from 2010. It is not a choice for start-ups that are eager to innovate, but for large enterprises where the key factors are predictability, security and lack of surprises. If your lead says «we need stability, not experiments» – you are in the right place.
11. Steelkiwi
The guys from Steelkiwi are a reliable option when you need to launch a project quickly and without unnecessary bureaucracy with complex business logic under the hood. They are not the architects of your global IT landscape, but in the prototyping stage or creating the first serious MVP show themselves brilliantly. Their strength is in the ability to build an admin or dashboard on pure React and TypeScript, which will not disintegrate at the first attempt to add a new feature. Look in their direction if you need a quality performer for a pointed but complex project.
How to make a choice? (Tips from inside)
Here is the whole sheet. But chasing tops, it’s easy to drown in beautiful sites and loud cases. Let’s be honest: there is no perfect company for everyone. Can be perfect – for your specific task, budget and corporate culture.
The choice is not on who is «cooler», but on who suits you. Here’s what you should focus on when conducting casting:
1. Understand that you are in pain right now. This is the most important point.
- Do you have a performance that «puts» on big data? Then you need not just a React developer, but an engineer who will have a pencil in his hand to understand the rendering, memorialization and device of your data. Look at Innovyts or Celadonsoft – their portfolio says they can do it.
- You need to embed the AI/ML model directly into the interface and make it work? This immediately narrows the circle to those who speak data science. Here ScienceSoft is almost a no-brainer.
- You have a legacy backend that needs to be kept alive, but with a modern React interface? This is the task of integration and patience. Iflexion and EPAM have done this hundreds of times.
- You need to quickly grow a team of 2-3 senior engineers for a specific module? Platforms like Toptal are designed for this.
2. Technical debt is for a long time. Who will give it to you?
Remember: any of the 10 columns can be made in a week. But a grid of 100+ columns with filtering, sorting, lazy loading and custom cells is already an architectural task. Ask the candidates not «What did you use?» but «Why did you choose AG-Grid instead of Tanstack Table? How did you solve the problem with virtualization during streaming?». The answers will show whether the architect thought about scaling or just hammered the nail with a hammer.
3. The price is not only hourly rate.
Yes, a developer from Celadonsoft or BairesDev may cost more on paper. But if it understands TA the first time, writes a clean code and does not create a techdebt that you will be scrapping the next two years – you are already saving. A cheap performer who will do «and that’s it» will cost tens of times more in the support phase.
