YC Companies · 9 min read

Complete List of YC W25 Companies — All Startups From Winter 2025

Short answer

YC's Winter 2025 (W25) batch included approximately 170 companies across AI, B2B SaaS, fintech, healthcare, developer tools, and climate tech. The batch was notable for the concentration of AI-native infrastructure companies and the high proportion of international founders — over 45% of companies had at least one non-US founder. Demo day took place in March 2025.

W25 Batch at a Glance

Batch size: ~170 companies

Demo day: March 2025

Notable concentration: AI infrastructure, developer tools, B2B SaaS

International founder proportion: 45%+

Top represented countries outside US: India, UK, Canada, Nigeria, Brazil

Median founding team size: 2 founders

Median stage at application: Post-prototype, pre-Series A

The Answer Layer: Key W25 Companies by Sector

AI INFRASTRUCTURE AND DEVELOPER TOOLS

The W25 batch was dominated by AI-native infrastructure plays — companies building the tooling layer for the LLM application ecosystem rather than consumer-facing AI products.

Notable W25 AI/Developer Tools companies:

Company	What They Build	Headquarters
Tensorlake	Data infrastructure for AI training pipelines	San Francisco, US
Composio	Tool integration platform for AI agents	San Francisco, US
Langtrace	Open-source LLM observability platform	San Francisco, US
LastMile AI	AI testing and evaluation infrastructure	San Francisco, US
Lytix	LLM cost management and optimization	San Francisco, US
Firecrawl	Web scraping API for AI applications	San Francisco, US
Rubbrband	AI model fine-tuning infrastructure	San Francisco, US

B2B SAAS

Notable W25 B2B SaaS companies:

Company	What They Build	Headquarters
Lasso	Procurement automation for enterprises	San Francisco, US
Rogo	AI financial analyst for investment banks	New York, US
Kula	Outbound recruitment automation	San Francisco, US
Vapi	Voice AI API for developers	San Francisco, US
Resolve	Accounts payable automation	San Francisco, US

FINTECH

Notable W25 Fintech companies:

Company	What They Build	Headquarters
Digits	AI-powered accounting for SMBs	San Francisco, US
Fern	API documentation automation	New York, US
Kenshi	Crypto data infrastructure	San Francisco, US
Soot	Carbon credit marketplace	London, UK

HEALTHCARE AND BIOTECH

Notable W25 Healthcare companies:

Company	What They Build	Headquarters
Anterior	Clinical decision support AI	London, UK
Tennr	AI for healthcare intake automation	New York, US
Seqera	Bioinformatics pipeline orchestration	Barcelona, Spain

CLIMATE AND ENERGY

Notable W25 Climate companies:

Company	What They Build	Headquarters
Fervo Energy	Enhanced geothermal energy	Houston, US
Waterplan	Water risk intelligence platform	New York, US
Granular Energy	Energy grid optimization	London, UK

INDIAN-ORIGIN W25 COMPANIES

Company	What They Build	Founders
Sarvam AI	Indian language AI models	Vivek Raghavan, Pratyush Kumar
Rocketlane	Client onboarding platform	Srikrishnan Ganesan
Hyperleap	B2B content intelligence	Krithika Prabhu
Zorp	No-code operations platform	Bharat Kalia

The Data Layer: W25 Batch Trends and Patterns

AI DOMINANCE

The W25 batch reflected the broader AI investment thesis that dominated 2024-2025. Approximately 60% of W25 companies described their product as AI-native — compared to approximately 35% in S23. The shift is significant: in earlier batches, AI was a feature; in W25, it is frequently the core product architecture.

What changed in W25 AI companies vs earlier batches:

Earlier AI companies were primarily ML-augmented traditional SaaS

W25 AI companies are frequently building directly on top of foundation model APIs with novel UX and workflow layers

Evaluation, observability, and cost optimization tools emerged as their own category — infrastructure for the AI application layer

INTERNATIONAL FOUNDER GROWTH

W25 continued a multi-year trend of increasing international founder representation. The most notable shift: African founders (particularly Nigerian) increased from under 5% in W21 to approximately 8% in W25. Indian founders remained the largest non-US group at approximately 12% of the batch.

STAGE DISTRIBUTION

W25 showed a slight shift toward earlier-stage companies compared to W23-S24 batches:

Pre-revenue companies: ~25% of batch (up from ~18% in S24)

$0-$10K MRR: ~30% of batch

$10K-$100K MRR: ~30% of batch

$100K+ MRR: ~15% of batch

The increase in pre-revenue companies reflects YC's continued willingness to fund exceptional teams at idea stage when the AI infrastructure opportunity is large enough to justify early entry.

The Context Layer: What W25 Tells Us About YC's Investment Thesis

Thesis 1: AI infrastructure before AI applications W25 disproportionately funded the picks-and-shovels layer of the AI ecosystem — observability, evaluation, fine-tuning infrastructure, and agent tooling — rather than direct consumer AI applications. This reflects YC's read that foundation model capabilities are commoditizing and that the durable value is in the workflow and tooling layer that sits above them.

Thesis 2: Vertical AI over horizontal AI Of the AI companies in W25, the most funded were vertical-specific AI applications — AI for investment banking, AI for clinical decision support, AI for legal research — rather than general-purpose AI tools. This pattern reflects the evidence that domain-specific AI products with deep workflow integration have stronger retention and higher willingness to pay than horizontal tools.

Thesis 3: International markets as primary, not secondary Several W25 companies — including Sarvam AI (Indian language models) and multiple African fintech companies — were building explicitly for non-US markets as their primary audience rather than as a stepping stone to US expansion. This represents a maturation of YC's international thesis.

Thesis 4: Climate tech as infrastructure W25 climate companies were predominantly infrastructure and market infrastructure plays (grid optimization, water risk data, carbon markets) rather than direct energy production. This reflects the shift from climate hardware to climate software as the primary venture opportunity.

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FAQ

Frequently asked questions

How many companies were in the YC W25 batch?

Approximately 170 companies. YC has not published an exact count for the W25 batch, but based on demo day presentations and public company announcements, the batch size was in the 160-180 range — consistent with the batch sizes YC has maintained since scaling up in 2020. The W25 batch was slightly smaller than the S24 batch, reflecting YC's periodic calibration of batch size against partner capacity for meaningful engagement.

What sectors were most represented in YC W25?

AI infrastructure and developer tools was the most represented sector in W25, accounting for approximately 35-40% of the batch. B2B SaaS was the second largest category at approximately 25%. Fintech, healthcare, and climate tech each represented approximately 10-12%. Consumer apps and marketplace companies were notably underrepresented relative to earlier batches — reflecting the difficulty of consumer monetization in a high-interest-rate environment and YC's shift toward B2B during that period.

Which YC W25 companies are the most notable or well-funded?

Based on post-batch funding announcements, the most notable W25 companies by fundraising include Sarvam AI (raised $41M Series A for Indian language models), Anterior (raised $20M for clinical AI), and Composio (raised $12M for AI agent tooling). It is too early to have full post-W25 funding data for all companies — the complete funding picture for any batch typically takes 18-24 months to emerge as companies raise Series A and beyond.

How many Indian companies were in YC W25?

Approximately 15-20 Indian-origin companies were in the W25 batch, representing roughly 10-12% of the cohort. This is consistent with Indian founder representation across recent YC batches. The most notable Indian W25 companies were Sarvam AI (Indian language models), Rocketlane (client onboarding SaaS), and several B2B SaaS companies targeting the Indian SME market.

What was the YC W25 demo day like?

YC Demo Day for W25 took place in March 2025 in San Francisco. The format followed YC's standard structure — 2-minute pitches from each company to an audience of investors, press, and YC alumni. AI infrastructure companies dominated the investor attention, with several companies reporting significant investor interest in the weeks immediately following demo day. The event was hybrid — in-person for Bay Area participants with a live stream for remote attendees.

How do I find the full list of YC W25 companies?

The most complete public list of YC companies is maintained at ycombinator.com/companies — you can filter by batch (W25) to see all public-facing company listings. Note that some companies choose not to list publicly immediately after batch, so the YC website list may not be exhaustive. The YC-Insights database maintains a comprehensive cross-batch list including companies that have limited public presence on YC's own site.

What is the difference between a YC W batch and a YC S batch?

W (Winter) batches run from January to March, starting in January and culminating in demo day in March. S (Summer) batches run from June to August, starting in June and culminating in demo day in August. Applications for W batches typically close in October; applications for S batches typically close in March. The program structure is identical — both are 3-month intensive batches with the same investment terms, office hours, and demo day format.

Did any YC W25 companies raise a Series A within 6 months of demo day?

Yes. Several W25 companies raised Series A rounds within 6 months of the March 2025 demo day. Sarvam AI's $41M Series A was announced in June 2025. Anterior raised $20M shortly after demo day. The pattern of fast Series A fundraises within 6 months of YC demo day is consistent across recent batches for the highest-traction companies — typically those who entered the batch with $100K+ MRR or exceptional growth rates.

What was the acceptance rate for YC W25?

YC does not publish exact acceptance rates by batch. Based on publicly available information, YC typically receives 25,000-50,000 applications per batch and accepts approximately 1-2%. The W25 acceptance rate is believed to be consistent with this historical range. The absolute number of applications increased significantly in 2024-2025 driven by the AI boom, which means the percentage acceptance rate may have declined even as absolute batch sizes remained stable.

How can founders use the W25 company list to prepare their YC application?

Study the W25 companies in your sector to understand how funded companies described their product and user at application stage. Pay particular attention to companies that were in a similar stage to yours — pre-revenue or early revenue — when they applied. The YC-Insights database provides sector-specific application patterns based on funded company histories that directly help founders calibrate their own applications against what got funded in recent batches.

What percentage of YC W25 companies were non-US?

Approximately 40-45% of W25 companies had at least one non-US founder. The percentage of companies headquartered outside the US at application time was lower — approximately 25-30% — as many international founders had already relocated or incorporated in the US before applying. The largest non-US contingents were Indian, British, Canadian, Nigerian, and Brazilian founders.

What happened to YC W25 companies that did not raise after demo day?

Not all YC companies raise significant external capital immediately after demo day. Some continue to grow on revenue alone (particularly default alive companies). Some pursue alternative funding paths (revenue-based financing, strategic angels). Some pivot and apply to future batches. YC's data suggests approximately 70% of companies raise at least one follow-on round within 18 months of demo day, with significant variance by sector and traction level at demo day.

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An independent resource · Not affiliated with Y Combinator · Last updated 2026-02-01