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# Plain-text mirror. Same words as the human page, minus everything a browser needed.
All ten companies below are still trading and still advertise mobile app development. That is a better result than I expected and a less useful one than it sounds, because the count was never the point. Two of the ten carry real staleness signals, and one sits behind a bot wall that no research tool can see past.
A disclosure first. I run Pixel Street, a web design and branding studio in Salt Lake, Kolkata. We design and build for Coca-Cola, ITC and Marico. Every company on this page sells into the same market I do, mostly from the same few square kilometres of Sector V and Rajarhat. A roundup of local agencies published on a local agency's own blog is not a neutral directory, and pretending it is would be the least credible thing on the page.
So I am not going to rank anybody. I have no basis for telling you that one of these teams writes better Kotlin than another, and neither does any other list on this subject. The numbers those lists quote are copied off the agencies' own marketing pages, and repeating a company's self-description on somebody else's blog does not turn it into a fact, it launders it. What I can check is the thing that actually wastes your afternoon: whether these companies still exist, still build mobile apps, and still trade where they say they do. I opened every one of their websites on 30 July 2026, and everything below is what that company's own site said on that date. Anything I could not check against a primary source is not on this page.
All ten companies below are still trading and still advertise mobile app development. That is a better result than I expected and a less useful one than it sounds, because the count was never the point. Two of the ten carry real staleness signals, and one sits behind a bot wall that no research tool can see past.
The shortest honest advice I can give: shortlist on whoever has shipped an app in your category, ask to see it live in the App Store or Play Store under the client's name, and then work through the questions worth asking any agency before you sign. No list on the internet, including this one, substitutes for that.
Listed alphabetically. The order carries no judgement and is not a ranking. "Footer year" is the copyright date the company's own site displays, the cheapest available proxy for whether anyone is still maintaining it.
| Company | Where its own site puts it | Footer year | What the fetch showed |
|---|---|---|---|
| Brainium Information Technologies | Salt Lake, Sector V (not confirmable from the site) | Not readable | Homepage blocks automated requests; server files show active maintenance in June 2026 |
| Capital Numbers Infotech | West Bengal registration; two development centres | 2012 – 2026 | Live; a listed public company on the BSE |
| CodeBuzzers Technologies | Sector V, Kolkata, plus Dubai and Amman | 2017 – 2024 | Live; footer two years behind |
| Digital Aptech | Block EN, Sector V, Salt Lake | 2026 | Live; blog current to January 2026 |
| Excellis IT | Kolkata; no street address published | 2025 | Live; media files uploaded June 2026 |
| Innofied | Ecospace Business Park, Rajarhat, Newtown | 2023 | Live and hiring, but the footer is three years stale and the blog stopped in December 2025 |
| Kazma Technology | 40 Weston Street, Kolkata 700013 | 2024 | Live; registered office in central Kolkata rather than the IT corridor |
| Red Apple Technologies | Mani Casadona, New Town | 2026 | Live; blog posts dated June 2026 |
| Unified Infotech | DN 53, Salt Lake Sector V, and New York | 2026 | Live; the most current site of the ten |
| Webskitters | Eco Intelligent Park, Salt Lake Sector V | 2026 | Live; award list runs to 2026 |
The screenshots below were taken in 2022, and several of these sites have been redesigned since. Read them as an archive rather than a preview.
[IMG: brainium app development agency]
Brainium is the one company here I could not read directly. Its homepage, service pages and sitemap all return a Cloudflare challenge to any automated request. That is a legitimate thing to do, and it also means no research tool, mine or yours or a language model's, can see what it sells. That matters more than it used to.
What the server does hand over is its robots.txt, and that file is informative. It was last modified on 6 June 2026, so somebody is maintaining the site. It disallows a backup directory named for 20 May 2026, and it lists hiring pages for app, AI/ML and Shopify developers. An operating company with an app practice, established from its own origin rather than a directory listing.
Website: www.brainiuminfotech.com. Expect to visit it in a browser rather than reach it any other way. I could not verify a phone number or postal address from the site itself, so I am not printing one.
[IMG: capital numbers web developer agency]
Capital Numbers is the only company here whose claims you can check against something other than its own marketing, because it is a listed public company: BSE scrip code 544343, security ID CNINFOTECH, classified under Information Technology. Audited accounts, mandatory disclosures and a share price mean a level of external scrutiny nobody else on this page is subject to, which is genuinely useful to know before you hand over a budget.
Its site lists mobile app development among custom software, web development, AI and machine learning, cloud engineering, e-commerce, UI/UX and QA. Footer 2012 to 2026, with current events and recent posts.
Website: www.capitalnumbers.com
Verify independently: BSE scrip code 544343 (CNINFOTECH)
[IMG: codebuzzers app development agency]
CodeBuzzers is a Kolkata company. Its own about page begins "Based in Kolkata", and the three offices it lists are Kolkata, Dubai and Amman.
The site is live and sells mobile app development (iOS, Android, native, hybrid and web) alongside web development, UI/UX, SEO and chatbot work. Worth flagging: the footer still reads 2017 to 2024. Two years behind is not evidence of a dead company, but it is the sort of thing a firm that maintains its own site fixes.
Address: Net Guru Building, 5th Floor, E 2-4, Bidhannagar, GP Block, Sector V, Kolkata 700091, West Bengal
Website: www.codebuzzers.com
[IMG: digital aptech moblie app agencyagency]
Digital Aptech's site is one of the better-maintained ones here: footer copyright 2026, blog posts dated January 2026, and a service list covering iOS and Android app development, web applications, custom software, AI and machine learning, staff augmentation, digital marketing and e-commerce. It publishes a full Salt Lake street address, which not every firm below does.
Address: EN-34, 9th Floor, Block EN, Sector V, Salt Lake City, Kolkata 700091, West Bengal
Website: www.digitalaptech.com
[IMG: excellist mobile app development agency]
Excellis IT is the youngest firm on this list. Its about page gives 2019 as the founding year, which is worth knowing if length of track record matters to you. Mobile application development sits in a service list alongside web development, e-commerce, cloud and DevOps, QA, UI/UX, AI/ML, blockchain and team extension.
The footer reads 2025. Against that, its media files carry a June 2026 upload path, so the site is being worked on even if the copyright line has not been touched.
Phone: (+91) 861 772 4646
Email: info@excellisit.com
Website: www.excellisit.com
The site publishes no street address, so I have none to give you. Ask for it before you sign anything.
[IMG: innofied app development agency]
Innofied needs a caveat, and it is the most interesting entry on the page for that reason. The company is clearly operating: the site is live, the Kolkata office at Ecospace Business Park is listed alongside San Francisco, Sydney, London and Pune, and the careers page carries eight open roles in Kolkata, one of them a Flutter developer. App development is plainly still on offer.
But the footer has read "Copyrights 2023" for three years, and the newest post on the blog is dated 3 December 2025. Neither is proof of anything. Both are exactly the pattern you see when a company's marketing site stops being anybody's job. If you shortlist Innofied, ask directly what they shipped in the last twelve months, which is a fair question to ask any of these firms, and the one this list cannot answer for you.
Address: Block 3B, 2nd Floor, Unit 204, Ecospace Business Park, Rajarhat, Newtown, Kolkata 700160, West Bengal
Website: www.innofied.com
[IMG: kazma technology app develop agency]
Kazma's site describes native mobile app development for iOS and Android, plus web development, AI and machine learning, chatbots, business intelligence, cloud support and packaged ERP, HRMS and CRM products. Footer 2024.
Worth noting where it actually sits. The registered office it publishes is 40 Weston Street, Kolkata 700013, which is central Kolkata rather than the Sector V and Rajarhat corridor most of this list works out of.
Registered office: 40 Weston Street, Kolkata 700013
Website: www.kazmatechnology.com
[IMG: redappletech app agency agency]
Red Apple Technologies Pvt. Ltd. runs a mobile and game development practice: iOS, Android, Flutter, React Native, plus game development, iGaming, art and design, and cloud work. Its footer reads 2026 and its blog carries posts dated June 2026, making it one of the more actively maintained sites here.
One detail worth catching: the company's CIN is registered in Delhi, not West Bengal, even though the office it publishes is Mani Casadona in New Town. Not a problem, but knowing which entity you are contracting with is basic diligence.
Address: Mani Casadona, West Tower, Unit 6WS1, 6th Floor, New Town, Kolkata 700156
Phone: +91 80177 79602
Email: info@redappletech.com
Website: www.redappletech.com
[IMG: unified infotech app developer agency]
Unified Infotech runs from New York and Kolkata, and its site was the most current of the ten: footer copyright 2026, press releases dated into 2026, live job postings. Mobile app development sits under its software engineering practice alongside website and custom software development.
The New York office is published openly rather than implied. If a US-facing engagement matters, that is the one here set up for it.
India: DN 53, Salt Lake, Sector V, Kolkata 700091
USA: 135 Madison Ave, New York, NY 10016
Website: www.unifiedinfotech.net
[IMG: webskitters web development agency]
Webskitters sells app development across hybrid, native, React Native, Flutter, Swift, Kotlin, Java and Objective-C, footer 2026. The award list on its about page runs continuously from 2013 to 2026, which at minimum tells you somebody updates that page.
Address: Eco Intelligent Park, Unit 7E, 7th Floor, Block EM, Plot 3, Salt Lake Sector V, Kolkata 700091
Website: www.webskitters.com
The standard advice in this genre is to check experience, read reviews, get a free quote, compare prices, check the portfolio and ask for references. That is six items, it is really two, and one of the two is close to useless. Here is what I would actually do, having sat on the other side of this conversation for years.
A case study is a designed artefact. A store listing is not. Ask for the link, check who the developer of record is, read the recent one-star reviews, and look at the last update date. An app that has not shipped an update in two years tells you how that relationship ended.
This separates a supplier from a landlord, and almost nobody asks it before signing. Whose Apple Developer account will your app live in? Whose Play Console? Who holds the repository, the signing keys, the push certificates? If the answer is the agency, you do not own your app. You are renting it, and the rent gets renegotiated the day you try to leave. I lost two companies before Pixel Street, and the lesson that survived both is that you never build your main asset on ground somebody else controls.
A quote produced before anybody has scoped your data model is a sales document, not an estimate, and comparing several of them mostly tells you who is most willing to guess low. For why the numbers in this city vary so wildly, see what web design costs in Kolkata. The same logic applies to apps.
For a single well-defined app with a fixed scope, a good freelancer can be the better answer; for anything needing sustained maintenance an agency usually is. Freelancer versus agency covers that trade-off properly, and it is worth settling before you start taking meetings.
No. They are listed alphabetically and I have deliberately made no quality judgement between them. I run a competing studio in the same city; any ranking I published would be worth exactly nothing to you, and every ranking you see elsewhere on this subject is built from the agencies' own marketing copy.
Because we do not build mobile apps. We do web design, branding and digital marketing. Adding ourselves to a list of app developers to catch the traffic would be the obvious move and also a lie.
Not on its own. A stale copyright year means the marketing site is not anybody's priority, which is common at firms whose work all arrives by referral. It becomes a real signal when it stacks with others: an abandoned blog, no recent releases, a careers page frozen in time. Two companies here show that stacking, and I have said which.
Every company on it was fetched on 30 July 2026. Local agency lists rot faster than almost any other kind, so if you are reading this long after that date, open the sites yourself first. Four minutes, and it is the most useful thing you can do with this post.
Different job, different shortlist. We keep a separately verified list of SEO companies in Kolkata, and Pixel Street itself does web design and eCommerce work from Salt Lake.
Ten companies, ten sites opened on 30 July 2026, ten still trading. No rankings, no borrowed client logos, and no project counts I cannot stand behind. That gives you a verified starting point and nothing more, which is honestly all a list like this can be.
Every figure in this article traces to one of the following. Publisher and publication date are recorded so a claim can be checked against its origin, and re-checked when the origin changes.