About Yellows sp. z o.o.
Yellows sp. z o.o. has been in business since 2016, delivering technology projects for clients. The company's main offerings are Mobile App Development. The company operates with a team of 10 - 49 professionals. Projects are generally billed around $50 - $99 / hr/hr. Yellows sp. z o.o. holds a 5.0-star rating across 5 client reviews. Their home base is Warszawa, Poland. This gives a quick snapshot of what to expect when working with Yellows sp. z o.o.
Where We Specialize
Industry Expertise
Typical Project Size
Yellows sp. z o.o. Reviews
Write a ReviewDesign system that brought consistency to a product that had accrued four years of visual debt
Sabrina Vollmer / Chief Innovation Officer - Rheintal Digital AGJun 06, 2026
Project summary: Our actuarial models had outgrown the reporting infrastructure feeding them. Data latency was introducing risk into pricing decisions that the business had decided it could no longer accept.
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.
Delivery timeline that proved achievable rather than optimistic, estimation accuracy that reflected real analysis rather than competitive bidding, scope discipline that prevented the feature creep we had experienced before
Time zone coordination required some deliberate overlap management from both sides in the first couple of sprints, after which we had an efficient async rhythm that worked for the whole project
Questions & Answers
CI/CD pipeline that transformed how our engineering team thinks about release risk
Niamh O'Sullivan / Director of Product - Munster Digital LtdMay 10, 2026
Project summary: Serialisation requirements under new traceability legislation had a compliance deadline. Our supply chain system required targeted development to meet it — generalist knowledge was not sufficient.
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.
Production system that has performed as specified since go-live without remediation work, documentation thorough enough to support internal maintenance, knowledge transfer that left our team genuinely capable
Time zone coordination required some deliberate overlap management from both sides in the first couple of sprints, after which we had an efficient async rhythm that worked for the whole project
Questions & Answers
A partnership that began with a single project and earned a place on our preferred vendor list
Yuki Hashimoto / Head of Product Development - East Asia Commerce KKMay 08, 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.
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.
Production system that has performed as specified since go-live without remediation work, documentation thorough enough to support internal maintenance, knowledge transfer that left our team genuinely capable
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
Project execution that matched the proposal in every dimension that mattered
Zofia Kamińska / CTO - Odra Tech StudioMar 05, 2026
Project summary: An international expansion required multi-currency, multi-language, and multi-warehouse capabilities that our existing platform could not support without a fundamental re-architecture.
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.
Delivery timeline that proved achievable rather than optimistic, estimation accuracy that reflected real analysis rather than competitive bidding, scope discipline that prevented the feature creep we had experienced before
Their discovery process is more rigorous than we were accustomed to and required more preparation from our side than we had initially allocated — but the quality of what followed justified every hour of it
Questions & Answers
End-to-end quality programme that halved our post-release incident rate inside three months
Cameron Aldrich / Head of Digital Operations - Northstar Logistics CorpFeb 28, 2026
Project summary: B2B customer churn was concentrated among accounts that had complained about portal usability. We needed a complete redesign of the self-service experience before the next contract renewal cycle.
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.
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
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
Questions & Answers
Publishing workflow that took our time-to-live from days to under an hour
Adriana Voss / Director of Platform Engineering - Cascadia Digital VenturesFeb 17, 2026
Project summary: Our legacy LMS had been built for a classroom-first world. Hybrid delivery had exposed its limitations and student satisfaction scores had reflected that for two consecutive years.
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.
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
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
AI models that replaced guesswork with evidence in decisions that matter most
Maja Söderström / Head of Product Engineering - Scandia Digital ABFeb 12, 2026
Project summary: Serialisation requirements under new traceability legislation had a compliance deadline. Our supply chain system required targeted development to meet it — generalist knowledge was not sufficient.
The integration layer was the part of the project I was most concerned about going in. Our system landscape is complex, several of the upstream APIs we relied on were poorly documented, and two third-party vendors had a history of unpredictable response times on integration questions. This team managed all of that. They documented what the upstream vendors could not, built resilience into the integration architecture where the upstream behaviour was unreliable, and delivered a solution that works as specified in production. I could not have asked for more.
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
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
User research that uncovered friction we had stopped noticing because it was always there
Abdullah Al-Shehri / Head of Innovation - Desert Tech VenturesJan 29, 2026
Project summary: A previous engagement had delivered something that worked in staging and struggled in production. We approached this project with greater rigour in vendor selection as a result.
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
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