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Marketing
RevEngine Referral Platform
UX/UI DesignFull-stack Development+3
Design Key
We become your product team
A senior squad and a named US product lead, embedded in your business. For companies that need software built and kept running, not a project delivered and dropped.
- Reply in 1 Business Day
- NDA on request
- US-led, senior only
Trusted by 50+ Companies
Industry leaders choose Design Key
6+Industries
18moAvg. Partnership
98%Client Satisfaction
About Us
Not a vendor. Your product team.
Design Key builds the software a business actually runs on, and then keeps running it. Most of our work is not a project with an end date. It is an embedded team inside a company that has product work every month, led by someone who owns the outcome rather than the ticket.
That shape is deliberate. The engagements that have lasted longest here are the ones where we took responsibility for a founder's most important product rather than delivering a scope and leaving. It is also why we say what we would do differently before we start, including the parts of a plan we would drop.
We are US-led, senior only, and we work inside your process rather than beside it. If you have been burned by a vendor before, that combination is usually what you were missing.
75%of clients stay with us long term rather than leaving at launch
50+web and mobile applications shipped to production since 2022
15+years the founder has spent building software and product teams
Case Studies
From SaaS startups to business software - we find the right technology for every case.
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Education & Non-Profit
Building a Digital Bridge for Educational Empowerment
UI/UX DesignWeb Development+3
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Entertainment
Building a Platform for the Acting Community
UX/UI DesignSaaS Design+3
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Finance
Crafting a Personal Brand in the Digital Space
UI/UX DesignWeb Development+3
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Sport
Sport Scheduling Platform
UX/UI DesignWeb & Mobile Development+3
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Healthcare
Doctor Joyce's Kids Weight Loss Program
UX/UI DesignFull-stack Development+3
Testimonials
Read what clients and partners say about our work
“Design Key delivered quality solutions to the problems the business uncovered not only were they helpful and knowledgeable but the entire process was well thought out.”
Brittany
Co-Founder of FocusVue
“I've had the pleasure of working with the Design Key that delivered quality solutions to the problems the business uncovered. The team was able to balance keeping pace with technology and delivering what was needed on time. I know this team will continue to do great things.”
Ryan Hoke
Product Delivery Manager at BeerBoard
“Daniel and his team have worked on several infrastructure development projects for me. They are excellent experts with exceptional client service and communication skills. Able to dig through complex project requirements and produce an end product that exceeds expectations.”
Lori Barao
Manager of Operations at MMI Direct
“Design Key did an excellent job by turning a concept into a working MVP. They know how to make the development process look easy, highlight underground stones, and suggest features and enhancements. Though I had a complex product, it was delivered on time and to spec.”
Ryan Wynch
Program Lead at Google
“DesignKey is spectacular and they do consistently exceptional work. There hasn't been anything they've told me they can't do… And I've asked for a lot over the years! I could not recommend them more highly.”
Henry Biggs
CEO at Eusabian Technologies
Leadership
Meet Our Founder
Daniel Killyevo is the founder of Design Key, a software studio in Tampa, Florida. He started it in 2022, after fifteen years building software inside other companies and on products of his own, watching clients receive exactly the build they asked for and not the product they needed.
He holds a Master's degree in Computer Science from Poltava National Technical University (2005-2011). Born in Tanzania to a Ukrainian mother and a Tanzanian father and raised in Ukraine, he now runs the studio from Tampa.
Daniel has more than 15 years in software development and product design and has delivered more than 50 web and mobile applications. He began his career as a developer and went on to work at Ciklum, at Corrigo before Terminix acquired it, and at JustEat, building products for companies at every stage from first customer to established revenue. Between 2014 and 2016 he also built and ran two revenue-generating products of his own, in real estate and recruitment technology.
His own work centres on architecting cloud-based systems, API and data integration, and building and scaling engineering teams. He has founded two software agencies.
50+
Web & Mobile Apps Delivered
10+
Years of Experience
HOW WE BUILD
Agentic delivery, with the quality bar held where it was
Our engineers work AI-assisted by default, and have since before it was the thing every agency says. What matters for you is not that we use it. It is where we let it run, where we do not, and who is accountable for the difference.
Agents do the mechanical work
Migrations, test scaffolding, dependency upgrades, refactors across hundreds of files, the first pass at a spike. The work that used to consume a junior engineer for a week is a supervised agent run, which is why our teams have no junior engineers on them.
Every change still passes a senior human
Agentic review runs on every pull request before a person sees it, so the human review is spent on architecture and product judgement rather than on catching a missing null check. The gate is a senior engineer, and it does not move.
Speed that does not borrow against the codebase
Shipping fast is easy once. Shipping fast in month eighteen depends on whether months one through six left the code legible. We hold the same review bar, test coverage and documentation standard whatever wrote the first draft.
We also build the things we use
Retrieval systems, agent workflows, model routing and evaluation harnesses, in production, for clients. The assistant on this page is ours. Teams that only consume AI tooling tend to find out where it breaks on your project rather than on their own.
HOW ENGAGEMENTS START
Ready when you are. Three ways to start.
Most engagements begin on the first rung and grow into the last. You are not committing to the destination by taking the first step, and the first two are credited toward whatever you build next.
Start here
Product & Architecture Review
You have a system that is straining, or a build you are about to commit to, and you want an honest read before you spend.
Two to three weeks, fixed price, credited in full against the build if you go ahead.
2 to 3 weeksCredited toward the build
Product & Architecture ReviewThe flagship
Embedded Product Team
You have product work every month and no team that can just run with it, or you are carrying a vendor who cannot.
A senior squad and a named US product lead who owns the outcome, inside your process, billed monthly.
Month to month
Embedded Product TeamFixed scope
Product Build
You know what needs to exist, and you need a team that will get the strategy right before it starts writing code.
Strategy and architecture first, then the build, ending in a team engagement rather than a handoff.
20 to 32 weeks
Product BuildYou do not have to pick the last one to start. A review or a prototype is how most of our longest relationships opened, and both are credited toward whatever you build next. Where those relationships ended up is the embedded team, years later.
Already know what you need?
Building a mobile app for a product you already have?
You do not have to start at the beginning. If you have a working product and need iOS and Android around it, or a mobile experience your web app never had, that is a well-worn path here and we can pick it up from wherever you are.
For agencies, MSPs and consultancies
Sell the work. We build it.
If your clients keep asking for portals, dashboards and integrations you have no team to build, we run delivery behind you. White-label or named, your relationship, your margin.
How the partnership worksStart with a conversation, not a brief
Thirty minutes with the person who would run the work, not a salesperson. Bring the problem you are trying to solve rather than a requirements list.
Book a callWe'll get back to you within 1 business day. Or size it yourself first.
Blog
Insights & Inspiration: Explore Our Blog
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Florida Fintech Dev Companies: 2026 Directory
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If you are an operator in Tampa Bay shopping for an AI integration partner, this guide names eleven firms doing the work locally - large enterprise shops, mid-size specialists, and small boutiques. Alphabetical, factual, with the criteria for inclusion and a how-to-choose checklist. We include ourselves with the same neutral treatment as everyone else.
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