Y Combinator has funded over 5,000 companies since 2005, including Airbnb, Dropbox, and Reddit. Closer to home, Irish founders that have gone through the programme too, including success stories like Stripe, Protex AI, and Noloco. But what actually happens during those three months in San Francisco, and is it right for your startup?
What is the Y Combinator accelerator?
Y Combinator runs four three-month accelerator ‘batches’ per year – winter, spring, summer, and fall (autumn). They invest $500,000 (roughly €430,000 at the time of writing) in every company using two separate SAFEs (introduced by Y Combinator, SAFEs are the dominant early-stage funding instrument globally): $125,000 for 7% equity, and an uncapped $375,000 with MFN provisions. Whilst the investment helps, most founders don’t do YC primarily for the money.
The programme centres on intensity. For three months, you’re surrounded by other founders, experienced partners, and a network of over 6,000 alumni. Your batch is split into small groups of 6 to 10 companies, giving you an intimate setting within the larger cohort. You’ll work with a dedicated YC partner – a successful founder – who knows your business and meets with you weekly.
Office hours form the core of YC. There are group sessions every fortnight and one-to-one sessions as often as you want them. What you discuss depends on your stage – early companies might focus on finding product-market fit, while later-stage startups work on scaling or fundraising strategy. The partners have advised hundreds of companies and have seen most problems before.
The programme kicks off with three days in-person in San Francisco, followed by weekly meetups throughout the batch. Each week brings talks from founders like those behind Stripe, Airbnb, and OpenAI, who share the unvarnished story of their early days. These talks are off the record, and that candour matters because the public version of most startup stories is sanitised compared to what actually happened.
Each batch culminates in Demo Day, where you present to specially selected investors and members of the press. YC helps you prepare for this and stays closely involved during the fundraising that follows, often speaking directly to investors to understand what they’re actually thinking versus what they’re saying.
Considerations for Irish founders
If you’re based in Ireland, there are some the practicalities to consider before applying to Y Combinator. The programme requires being in San Francisco for three months – that means visas, accommodation, and the knock-on effect on your personal life. YC works with immigration lawyers who’ve helped hundreds of founders navigate USA visa requirements, but it’s still a significant consideration.
For company structure, if you’ve already incorporated in Ireland, you’ll need to create a parent company in the USA, Singapore, or the Cayman Islands, with your Irish entity becoming a subsidiary. Many companies do this each batch, and YC connects you with lawyers to manage it, but it requires effort on your part.
The investment itself – $500,000 – will potentially go further in Ireland than in San Francisco, which is useful given you’ll likely return home after the batch. You can use it for anything that helps your business, typically starting with paying yourself a salary so you can work full-time. If you have a mortgage or student loans, you can cover those from what you pay yourself.
The time commitment is lighter than most founders expect – a few hours weekly if you participate in everything. All parts are optional; YC expects you to spend your time in whatever way maximises your odds of success. Many founders worry that YC will distract them from building, but the opposite tends to be true. The three months are structured specifically to let you focus completely on your startup.
When Y Combinator makes sense for founders
Y Combinator funds companies at all stages. Forty percent of each batch is just an idea – most have no revenue. But they also fund companies that are much further along: 7% of recent batches had over $50,000 in monthly revenue when accepted. Companies like Rappi and MessageBird did YC whilst making well over $1 million yearly.
You don’t need to be early-stage. As long as you haven’t already raised a Series A from VCs, YC can probably help. Each batch includes many companies that have already raised over €950,000. If you’ve raised at a higher valuation than YC’s investment implies, that’s fine too – a large percentage of each batch has. The question isn’t about valuation; it’s whether YC can improve your outcome by at least 7%.
A lot of Irish startups are in the B2B SaaS, fintech, medtech, and climate tech spaces. YC has funded companies across all these sectors and many others, from microbes to fusion reactors to coffee carts. They don’t limit themselves to software, though the network does skew towards tech startups.
Solo founders can apply, although YC advises that it’s much harder to scale a single-person startup. If you want a co-founder, they run a matching service; the founding team needs the skills to build the product themselves rather than outsourcing it. For most businesses, that means having a technical co-founder.
You can apply whilst working full-time or studying, but if accepted, YC expects you to commit full-time during and after the batch. You can also apply if you’ve already done another accelerator (like one of the Irish accelerators we explore in this blog) although they may expect you’ve reached a higher level of progress.
What happens after Y Combinator?
Y Combinator doesn’t end after three months. Office hours continue year-round for all alumni. The community – probably the most powerful in the startup world – remains accessible through Bookface (their internal platform), WhatsApp groups for specific sectors, and annual reunions.
You’ll get discounts and free accounts for over 100 products, including hundreds of thousands of euros in free cloud hosting. The YC Startup Directory showcases your company to potential customers, investors, and hires. Work at a Startup helps you recruit, from first employees to senior hires.
The credibility matters too. When YC companies do well, the whole community benefits. Early adopters, investors, and press are often more willing to look at YC founders, even first-timers. While execution matters, YC will open doors for you. For example, SolidRoad, a Dublin startup founded in 2023 and part of the YC winter 2025 cohort, has already raised $8 million in funding (including a $6.5 million seed round led by First Round Capital).
The Y Combinator application process
Applications open for each batch with a clear deadline. Apply before it and you’ll hear back by a specific date. Apply after and they’ll still consider you but can’t promise when they’ll respond (their website says they fund many late applications each batch). Don’t panic, if you miss one batch you can just apply to the next one.
If your application is promising, you’ll get a video interview. They typically decide the same day and give everyone who interviews detailed feedback. About half of each batch applied multiple times before being accepted. If you’ve applied before and didn’t get in, apply again, as progress since your last application is a strong signal. You don’t need to know anyone at YC – they consider all applications equally, unlike many investors who rely on introductions.
The application form asks about your idea, your team, and your progress. They want to understand what you’re building and why you’re the right people to build it. If something material changes after you submit – like adding or removing a co-founder – you can submit an update.
Should you apply to Y Combinator?
Whether to apply comes down to your answers to questions such as: Can you commit three months in San Francisco? Will your company benefit enough from YC to justify 7% equity? Do you want to be part of this network?
For many Irish founders, particularly in B2B SaaS or sectors where the US market matters, YC offers access to a network and knowledge base that’s difficult to replicate in Ireland. The partners have seen thousands of companies and can spot problems early. The alumni can open doors to customers, investors, and talent.
The potential to improve your trajectory matters as much, if not more, than the investment you’ll get. The Irish startup ecosystem has grown substantially, but it’s still small compared to Silicon Valley. YC gives you three months inside that world, with people who want to help you succeed. Whether that’s worth the three months and effort required depends on you, but for the right founders at the right time, it’s transformative.
