Seattle has always been a magnet for innovation, with its unique blend of world-class universities, a thriving tech scene, and an entrepreneurial spirit that refuses to slow down. In 2025, that momentum translated into a wave of Series B funding rounds that are shaping the future of industries as diverse as food, biotech, energy, and cybersecurity.
This blog post spotlights Seattle-based companies that secured Series B funding this year. By examining their breakthroughs, their investors, and their growth plans, we gain a glimpse of the new directions innovation is taking in one of the most dynamic startup hubs in the United States.
Rebellyous Foods – $2.4M
Rebellyous Foods has spent years working on a challenge that sits at the intersection of food, sustainability, and engineering: creating plant-based chicken that is both affordable and scalable.
In January 2025, the company secured $2.4 million in an extension of its Series B round, bringing its total Series B fundraising to roughly $12 million.
What makes Rebellyous unique is not only its plant-based product line but also its engineering-first approach. The startup is developing the “Mock 2” automated production system, designed to reduce the cost of plant-based meat manufacturing while maintaining quality.
By focusing on automation, Rebellyous is addressing one of the biggest barriers to widespread adoption of alternative proteins: price parity with traditional meat.
The funding will help the company grow sales and bring its products into more institutional settings like schools, cafeterias, and hospitals. With sustainability high on the global agenda, Rebellyous continues to make the case that good food can also be a force for positive change.
IUNU – $20M
Agriculture is going digital, and IUNU has taken a front-row seat in this transformation. In April 2025, the Seattle-based agtech company raised $20 million in an extended Series B round.
Its flagship product, Luna, uses rail-mounted cameras and computer vision to monitor greenhouse crops in real time, identifying pests, disease, and nutrient deficiencies before they spread.
This investment, led by S2G Ventures, reflects the growing interest in precision agriculture. By leveraging artificial intelligence and automation, IUNU allows farmers to reduce waste, increase yields, and better manage resources.
Greenhouses outfitted with Luna can track every plant, generating data that gives growers actionable insights at scale.
The company’s expansion plans include strengthening its footprint in North America and Europe, as well as hiring engineers and commercial talent to refine its solutions. In a world facing climate uncertainty, IUNU’s approach shows how technology can help secure the future of food.
Mast Reforestation – $25M
In February 2025, Mast Reforestation, formerly known as DroneSeed, closed a $25 million Series B round co-led by Pulse Fund and Social Capital. Mast combines drone technology, carbon capture, and forestry expertise to accelerate the restoration of wildfire-ravaged landscapes.
The company not only reforests with precision drones but also innovates in carbon capture through “wood vaulting,” a process where burned trees are buried to sequester carbon permanently. This dual approach addresses both ecological restoration and climate change mitigation.
Investors such as Elemental Impact, Spero Ventures, and Thistledown Capital backed Mast’s vision of reimagining reforestation at scale. With wildfires becoming more frequent and destructive, Mast’s model represents a way to transform crisis into opportunity, bringing both environmental and economic value to communities.
Dropzone AI – $37M
Cybersecurity remains a relentless battle, and Dropzone AI is stepping up with a bold vision. In July 2025, the company announced a $37 million Series B led by Theory Ventures, with support from Madrona Venture Group, Decibel, and In-Q-Tel.
Dropzone AI develops autonomous security agents capable of triaging alerts and conducting penetration tests, tasks typically requiring hours of human attention. By automating these critical functions, the startup aims to ease the burden on overworked security teams while improving response times.
The company plans to use the funds to grow its engineering and sales teams, further refine its product, and meet rising demand from enterprises drowning in security alerts. With cyber threats escalating, Dropzone AI embodies how automation and artificial intelligence can transform defensive strategies.
Zeno Power – $50M
In May 2025, Zeno Power raised $50 million in a Series B led by Hanaco Ventures, with participation from Seraphim, JAWS Ventures, and others. Zeno develops compact nuclear batteries that use strontium-90 to generate reliable power for extreme environments such as space, the Arctic, and undersea missions.
The company envisions a future where exploration and communication are no longer constrained by battery life or fuel limitations. By producing long-lasting, maintenance-free power sources, Zeno is unlocking opportunities for lunar bases, maritime operations, and other remote applications.
This new funding will allow Zeno to scale production and prepare full system demonstrations slated for 2026. In an era when energy resilience has become critical, Zeno’s approach offers a powerful blend of science and practical innovation.
XBOW – $75M
June 2025 saw the rise of XBOW, a Seattle startup specializing in offensive cybersecurity. The company raised $75 million in a Series B round led by Altimeter Capital, with participation from Sequoia Capital and Nat Friedman.
XBOW’s platform autonomously scans and attacks software applications to uncover vulnerabilities, essentially mimicking the work of elite human hackers. By automating this process, the company provides continuous, large-scale penetration testing, helping organizations identify weaknesses before attackers do.
This funding will accelerate XBOW’s go-to-market strategy and enable it to build out its AI-driven capabilities further. In a cybersecurity landscape where threats evolve faster than defenses, XBOW’s technology offers enterprises a chance to stay one step ahead.
Eigen Labs – $70M
Eigen Labs made headlines in mid-2025 by securing $70 million through a token-based Series B led by Andreessen Horowitz’s crypto arm. The company is developing EigenCloud, a platform that extends Ethereum’s restaking protocol to bring verifiable computing to broader applications.
Innovation lies in creating systems where trust and verification are embedded at the infrastructure level. Eigen aims to make blockchain-level security and transparency accessible to developers working on projects ranging from decentralized finance to supply chain monitoring.
With the new funding, Eigen is scaling its developer tools and preparing for public network launches. In a space still searching for reliable infrastructure, Eigen positions itself as a cornerstone of the next blockchain era.
Supio – $60M
Supio entered 2025 with an ambitious plan to revolutionize legal workflows, and in April it secured $60 million in Series B funding. Sapphire Ventures led the round, joined by Mayfield Fund and Thomson Reuters Ventures.
The company provides AI-powered tools that allow law firms to organize and analyze massive case files quickly, reducing the administrative burden that slows litigation. For mass tort and personal injury firms, this efficiency translates into faster preparation and stronger outcomes.
Supio’s growth strategy includes expanding its product suite and entering new markets. By marrying artificial intelligence with legal expertise, Supio is redefining how justice is delivered at scale.
Curevo Vaccine – $110M
Seattle’s biotech community gained a boost in March 2025 when Curevo Vaccine announced a $110 million Series B led by Medicxi, with participation from OrbiMed, Sanofi Ventures, and others.
Curevo is advancing a shingles vaccine designed to improve upon existing treatments through a proprietary epitope-based platform.
The funding supports Phase 2 clinical trials of its lead candidate, which has the potential to provide more effective and longer-lasting protection than current vaccines. If successful, this breakthrough could significantly reduce the global burden of shingles, a disease affecting millions each year.
With a strong lineup of healthcare investors, Curevo is poised to accelerate its clinical program and bring its vaccine closer to market, reinforcing Seattle’s reputation as a hub for biotech innovation.
Tune Therapeutics – $175M
January 2025 began with a bang when Tune Therapeutics secured $175 million in Series B financing. The round, led by New Enterprise Associates, also included Regeneron Ventures and Yosemite Ventures.
Tune is pioneering epigenetic editing, a groundbreaking approach that adjusts gene expression without altering DNA sequences. Its first clinical program targets chronic hepatitis B, with trials already underway. This method holds promise not only for infectious diseases but also for cancers and rare genetic conditions.
The new capital will allow Tune to expand its therapeutic pipeline and scale its research platform, TEMPO. By taking epigenetics from the lab to the clinic, Tune is redefining the boundaries of modern medicine.
Seattle’s Momentum Continues
The companies highlighted here reflect Seattle’s extraordinary breadth of innovation. From sustainable food and reforestation to cutting-edge cybersecurity, blockchain, biotech, and energy, these startups demonstrate how diverse ideas can thrive in the same ecosystem.
Their Series B rounds in 2025 represent more than just financial milestones. They are signals of confidence from investors and commitments to solving pressing challenges. As these companies grow, they will shape industries, inspire talent, and reinforce Seattle’s position as one of the most dynamic startup hubs in the world.
Contact us to learn more about our software development services, and follow us on LinkedIn for more tech trends.
FAQ
What is a Series B funding round?
A Series B round is the second significant stage of venture capital financing, typically used by startups to scale operations, grow teams, and accelerate product development after proving market fit.
Which Seattle company raised the largest Series B in 2025?
Tune Therapeutics raised the largest round with $175 million in January 2025. The company specializes in epigenetic gene editing therapies.
Are the startups from multiple industries or mainly tech?
Seattle’s 2025 Series B rounds spanned a wide range of industries, including biotech, cybersecurity, agtech, legal tech, blockchain, food innovation, climate tech, and energy.
How much Series B funding did Seattle startups raise in total in 2025?
Collectively, the ten companies featured raised more than $600 million, underscoring Seattle’s strength as a cross-industry innovation hub.
Who were some of the top investors in these rounds?
Prominent investors included New Enterprise Associates (NEA), Andreessen Horowitz, Sapphire Ventures, Hanaco Ventures, Medicxi, and Madrona Venture Group, alongside sector-focused funds and strategic backers.
What does this funding mean for Seattle’s startup ecosystem?
These rounds show investor confidence in Seattle’s ability to generate breakthrough ideas across industries. The capital will fuel job growth, accelerate product launches, and reinforce Seattle as a leading U.S. startup hub.
