About 21CN
Businesses looking for a reliable technology partner often consider 21CN. 21CN focuses on Web Development and Mobile App Development. 21CN employs 10 - 49 people. 21CN operates out of Chorzów, Poland. These details offer a useful starting point when evaluating 21CN.
Where We Specialize
Industry Expertise
Typical Project Size
21CN Reviews
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Adriana Voss / Director of Platform Engineering - Cascadia Digital VenturesJun 10, 2026
Project summary: Our trading platform had been extended incrementally for seven years. Latency was degrading, technical debt was compounding, and a clean rebuild was no longer optional.
Six months after go-live our platform is processing three times the transaction volume we specified in the original brief. The architecture choices made during discovery accommodated that growth without remediation work. That is the difference between a team that designs for what you tell them and a team that designs for what you are likely to need. We are in conversation about a Phase 2 engagement and I expect to be using this partnership for several years.
Commercially transparent throughout — no hidden assumptions, no bill shock at the end, change requests that were fair and clearly explained rather than used as a margin-recovery mechanism
Pipeline availability for kickoff required a few weeks of lead time — in hindsight that selection pressure means you are working with a team that is in demand for the right reasons
Questions & Answers
Observability stack that caught three production issues before any user reported them
Elliot Thorne / Managing Director, Tech - Redwood Capital AdvisorsApr 10, 2026
Project summary: Our audience data was fragmented across eight tools with no single identity layer. Personalisation had become impossible without first solving the data foundation.
The technical quality of the final deliverable is the easiest thing to point to. The automated test coverage is thorough, the deployment pipeline is reliable, the documentation is genuinely useful rather than ceremonially produced. But the metric I keep returning to is the number of post-launch conversations we have not had to have. No incident calls at two in the morning. No emergency patches. No retrospective discussions about what went wrong. The absence of those events is the evidence I would show to someone considering this vendor.
Architectural decisions designed for longevity rather than just the current brief, thorough automated test coverage, post-launch stability that validated every technical choice made during discovery
The quality of documentation they produce means our team needed to set aside dedicated review time to do it justice — a minor scheduling point rather than a genuine criticism
Questions & Answers
A platform our sales team adopted within the first week without a single complaint
Sabrina Vollmer / Chief Innovation Officer - Rheintal Digital AGMar 07, 2026
Project summary: Our engineering capacity was committed to maintaining existing systems and could not absorb a net-new build of this complexity. An external partner with the right skills was the only viable option.
The project brief was ambitious and we had received proposals ranging from two to five times our eventual budget from other vendors. This team came back with a proposal that was commercially realistic and technically credible — and then delivered against it. That alignment between proposal and outcome is not something I take for granted. I have been on the other side of it enough times to know it requires both honesty in the sales process and discipline in delivery. We experienced both.
Collaborative culture that made the team feel like a genuine extension of our organisation, strong asynchronous communication across time zones, zero-drama handling of the inevitable mid-project changes
The engagement was priced at the quality level rather than the budget level. We evaluated the alternatives and concluded that the delta was a reasonable premium for the reduction in delivery risk
Questions & Answers
Gameplay feel that matched the design intent precisely — a harder achievement than most realise
Declan Hartley / Chief Digital Officer - Southern Cross TechnologyFeb 11, 2026
Project summary: Our engineering capacity was committed to maintaining existing systems and could not absorb a net-new build of this complexity. An external partner with the right skills was the only viable option.
What made the most difference in practice was the quality of the engineering judgment on this team. Not the ability to execute a specification — that is a baseline expectation. The ability to recognise when a specification was suboptimal, explain why, propose an alternative, and support the client in making a decision about it. That consultative dimension elevated the output beyond what the brief described and resulted in a product that is more fit for purpose than the one we had originally specified.
Architectural decisions designed for longevity rather than just the current brief, thorough automated test coverage, post-launch stability that validated every technical choice made during discovery
Pipeline availability for kickoff required a few weeks of lead time — in hindsight that selection pressure means you are working with a team that is in demand for the right reasons
Questions & Answers
Automation that freed our team from repetitive analysis and let them focus on strategy
Ji-Woo Park / VP of Engineering - Seoul Digital CorpFeb 09, 2026
Project summary: Track-and-trace capability had gone from a differentiator to a table-stakes requirement and our platform had neither. We needed to close the gap before our next enterprise tender cycle.
We gave this team an aggressive timeline, a technically complex scope, and a client-side project team that was stretched thin and not always available at the speed the engagement required. They absorbed all of that gracefully. Where they needed input they were precise about what they needed and when. Where they could proceed independently they did. The result was a delivery that landed on time despite the constraints on our side, which I regard as evidence of genuine professional maturity.
Architectural decisions designed for longevity rather than just the current brief, thorough automated test coverage, post-launch stability that validated every technical choice made during discovery
Pipeline availability for kickoff required a few weeks of lead time — in hindsight that selection pressure means you are working with a team that is in demand for the right reasons
Questions & Answers
IT partner embedded deeply enough to understand our business, not just our ticket queue
Jia Hui Tan / VP of Engineering - RedDot Technologies Pte LtdFeb 04, 2026
Project summary: Customer expectations had reset and our conversion funnel data showed precisely where we were losing them. We needed a commerce platform capable of delivering the experience our competitors already had.
The thing that retrospectively seems most significant is how little drama there was. Complex technology projects tend to accumulate incidents, escalations, and tense conversations. This one did not. Problems were surfaced before they became incidents. Scope changes were handled with process rather than conflict. Risks were managed rather than avoided. That level of maturity is rare in my experience and it made the delivery feel almost effortless from our side, which I know it was not from theirs.
Senior-level engineering presence throughout the entire project, not just during the pitch, honest and commercially fair handling of scope changes, codebase that our internal team praised on review
The quality of documentation they produce means our team needed to set aside dedicated review time to do it justice — a minor scheduling point rather than a genuine criticism
Questions & Answers
A studio team who played the game obsessively and built it accordingly
Beatriz Cavalcanti / Chief Digital Officer - Cerrado Tech SAJan 31, 2026
Project summary: Lean manufacturing initiatives required real-time OEE data at the line level. Our existing systems could not provide it without significant manual aggregation.
The technical quality of the final deliverable is the easiest thing to point to. The automated test coverage is thorough, the deployment pipeline is reliable, the documentation is genuinely useful rather than ceremonially produced. But the metric I keep returning to is the number of post-launch conversations we have not had to have. No incident calls at two in the morning. No emergency patches. No retrospective discussions about what went wrong. The absence of those events is the evidence I would show to someone considering this vendor.
Senior-level engineering presence throughout the entire project, not just during the pitch, honest and commercially fair handling of scope changes, codebase that our internal team praised on review
Their insistence on a detailed functional specification before development began felt like friction at the time. In retrospect, it was the reason the development phase ran without the ambiguity that has derailed similar projects for us previously
Questions & Answers
Custom platform that our engineering team is still proud to maintain two years later
Priya Chandrasekaran / VP of Data & AI - Wavefront Analytics IncJan 17, 2026
Project summary: The project had a board-facing delivery date tied to a strategic initiative. We needed a partner who would treat that date as their own, not ours.
We had worked with three agencies before this engagement. The comparison is not flattering to the others. What distinguished this team was a systematic approach to understanding the problem before proposing a solution — something that sounds obvious and is practiced far less often than it should be. The delivery phase ran to schedule, the codebase is clean enough that our internal engineers made positive comments during handover review, and we have not logged a critical incident in five months of live operation. We intend to use them for our next phase of work.
Collaborative culture that made the team feel like a genuine extension of our organisation, strong asynchronous communication across time zones, zero-drama handling of the inevitable mid-project changes
We underestimated the input required from our subject matter experts during the requirements phase. The team flagged this early but our resource planning did not fully reflect it — our responsibility, not theirs