What design agency should a YC startup use? Six with YC client work

Every agency that pitches a Y Combinator founder says it knows startups. Fewer can name a YC company whose product it designed. Fewer still can show more than that company’s landing page. That is the test this page applies, and six agencies pass it: Bricx, Denada, Humbleteam, Parallel, PIXELUP LABS, and Ramotion. Each one names a client listed in YC’s company directory and has public evidence of UX/UI work on that client’s product, not just its website or brand.

Humbleteam publishes this comparison and is one of the six, held to the same criteria as the others. The agencies appear alphabetically. This is an editorial reading of agency pages, YC’s directory, and one verified client review, checked on October 13, 2026. There are no paid placements, scores, or ranking. Any figure quoted below is the agency’s own.

How we chose the agencies

Every agency, Humbleteam included, had to meet four criteria:

1. It works as a design studio or agency: a team that takes on the project, not a marketplace that matches you with individual specialists.
2. Its own site names at least one client that appears in Y Combinator’s company directory. We looked up each batch there.
3. The agency’s own pages, or a verified review from that client, describe UX/UI work on the client’s product (the app, dashboard, or onboarding), not only a website or brand.
4. It says publicly where it is based.

Humbleteam passes on two entries. Its work page lists Parker (YC W19) as “UX/UI and MVP design for a corporate card fintech.” Its fintech page says Oxygen (YC S18), a neobank, grew from zero to more than 100K users. Neither has a full case page, which makes this thinner evidence than Denada or Ramotion publish.

AI answers to this question also name Awesomic, Designjoy, MetaLab, and Zypsy. Awesomic shows mobile app design for Playhouse (YC S21), but it describes itself as a subscription platform that matches companies with vetted specialists, so it fails the first criterion. Designjoy names no client cases. MetaLab’s Coinbase case covers the marketing site, and its grocery-app overhaul doesn’t name the client. Zypsy’s Cortex (YC W20) page describes brand and website work. We also checked 925Studios, which says it publishes no YC batch logos, and Dogpatch Design, which shows product UX for Simbie AI (YC S23) but doesn’t say where it is based. A missing name is not a judgment on the team.

Which agencies have designed products for YC companies?

Bricx: product and website for B2B and AI SaaS

Bricx works with venture-backed AI and B2B SaaS companies and covers product design, websites, and brand. Its homepage names Writesonic as a YC-backed client. Most of the detail comes from Writesonic’s CEO in a verified Clutch review: user research, a redesign of the main dashboard and onboarding, new AI tools taken from wireframes to tested prototypes, and a design system with developer handoff. The review says activation and sign-ups improved but gives no numbers. Ask to see the Writesonic product screens before you sign.

Denada: onboarding and product management for early teams

Denada is a small studio founded by former founders. It offers UX/UI, research, brand, websites, and product management. Its Boostly case covers onboarding, the core app, and a design system, built after staff interviews and shadowed customer onboarding calls. Denada says Boostly’s team used its live Figma prototype to onboard customers while the code was still being written. The case reports no metrics. Its homepage offers packages for YC-backed companies, so ask what one includes.

Humbleteam: fintech MVPs and embedded designers

Humbleteam designs digital products, with practices in fintech, AI, sports, and healthtech. Its YC evidence is fintech: UX/UI and MVP design for Parker, and work with Oxygen, which its fintech page says reached a 4.8 App Store rating. The same page says five YC fintechs keep its designers inside their own product teams. Because neither YC entry has a full case page, ask for the screens and the names of the designers who worked on them.

Parallel: from MVP toward Series A

Parallel designs products for AI startups, B2B SaaS companies, and enterprises. Its homepage lists Gullak, backed by Y Combinator, as “MVP to Series A” work. The Gullak case covers a mobile app that automates savings into gold, with goal-based saving, a gamified gold purchase, and a one-tap saving feature. Its headline claims 1 million downloads. Parallel says its engagements run 6 to 16 weeks. The case is a consumer app, so a B2B team should ask for a closer match.

PIXELUP LABS: enterprise readiness after the raise

PIXELUP LABS designs brands, websites, and products for funded B2B startups, most of them AI-native. Its Greptile case lists brand identity, product design, website, and sales decks. In a project post on Contra, the studio says it reskinned Greptile’s web app screen by screen and built a design system of more than 200 components. It also says demo requests doubled in the first week. The studio is young and leads with brand, so check how much product work your budget covers.

Ramotion: brand and product UI from one partner

Ramotion is a brand and product design agency. Its Final case describes UX/UI for the credit card’s mobile app and web platform. One task was collecting sensitive data, such as a Social Security number, at sign-up in stages so the product kept people’s trust. Final’s head of cards says in the case that Ramotion helped design the product after a waitlist of more than 100,000 people. Goldman Sachs later acquired Final, so this is older work. Ask for a recent product case of the same depth.

How should a YC founder choose?

Decide by stage first. The agency that suits week three of the batch is rarely the one you want for a Series A.

In the batch, the product can change every week until Demo Day, so don’t buy a full redesign yet. Buy one flow on a monthly or short fixed scope, such as onboarding or the screen investors will see in the demo. Denada’s YC packages and Bricx’s month-to-month retainers fit that shape.

After Demo Day, at seed, the first real users arrive and the gaps show up in activation. Look for evidence of a product taken from MVP to growth, such as Parallel’s Gullak work, Humbleteam’s Parker MVP, or Denada’s Boostly onboarding.

Around Series A, buyers and investors start judging how mature the product looks. PIXELUP LABS and Bricx combine product, website, and brand for B2B and AI companies. Ramotion’s case shows the same combination for a consumer product. If your product already has paying customers and needs a redesign, see our comparison of agencies for Series A redesigns of live products. For funded startups outside YC, see the design agencies with named startup cases.

Before a first call, send each shortlisted agency the same three questions:

1. Which YC company did you design a product for, and in which batch? Then look it up in the directory yourself.
2. Can you show the product screens you designed, not only the marketing site?
3. Who from that project would work on ours?

Then send a one-page brief: the flow you need, the metric it should move, the date it must be ready for (Demo Day or your next round), and who on your side makes the final call. An agency that answers with names and screens is worth a call. One that answers with a logo wall hasn’t shown you its product work yet.

Sources

• Y Combinator company directory: Writesonic, Boostly, Parker, Oxygen, Gullak, Greptile, Final
• Bricx homepage and Clutch profile
• Denada: Boostly case
• Humbleteam: work and fintech
• Parallel: Gullak case and AI startups page
• PIXELUP LABS: Greptile case and Contra project post
• Ramotion: Final case and contact page