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Worldbuild

New York, NY · Invests in US · Website

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Pre-SeedSeedMedia & EntertainmentAI & Machine LearningDeveloper ToolsHealthcare & BiotechClimate & EnergyDeveloper Tools & InfrastructureClimate & Clean EnergyHealthcare & Digital Health

Thesis

Worldbuild invests in creative technologists building in one of two categories: (1) Model Economy Infrastructure — compute, data, energy, and security that AI models need to improve; (2) Post-Skeuomorphic Applications — workflows that only become possible because of AI. The fund avoids specialist AI tools bolted onto existing SaaS workflows.

Likely not a fit for

Specialist AI tools that wrap existing workflows without fundamental innovation; companies fighting scaling laws rather than working with them; traditional software digitization plays with AI added on.

How they invest

Fund status
Actively deploying
Decision process
Solo GP

Partners & team

1 contact on file

SS

Sumeet Singh

Founder and Managing Partner · Primary contact

Portfolio

SF ComputeEnterprise Software

SF Compute sells time on large-scale GPU clusters, allowing customers to enter contracts that can be exited by selling back to a liquid market, thus reducing the risk associated with long-term agreements.

BrowserbaseDeveloper Tools Infra

Browserbase is the all-in-one platform developers need to host, manage, and monitor headless browsers in the cloud.

AetherfluxClimate Clean Energy

Aetherflux's mission is to deliver energy to planet Earth through space solar power. The company aims to collect sunlight in Low Earth Orbit and transmit that power via infrared lasers to portable ground receivers, providing energy access where traditional delivery is expensive or dangerous.

TruffleDeveloper Tools Infra

Truffle is a development platform that enables users to build and deploy applications using the Truffle SDK. It provides tools for creating, testing, and deploying apps, including a simple weather-checking application that interacts with external APIs.

Fractal PowerClimate Clean Energy

Fractal Power builds and operates the critical infrastructure layer to the modern economy, delivering energy where and when it's needed most through a vertically integrated platform.

InterfereEnterprise Software

Interfere is the experience layer for modern product teams, providing software that can detect, triage, and fix bugs automatically without human intervention.

Flower ComputerEnterprise Software

Flower Computer is developing innovative communication technologies, including Yuma, a chat app that allows interaction with everyday objects. They also have a Hivemind skill-sharing system and a fast static embedding model.

Armory MedicalHealthcare Digital

Armory Medical is an AI lab developing intelligent systems to automate healthcare operations, allowing staff to focus on critical tasks. They aim to revolutionize healthcare delivery in the U.S.

Company PicnicConsumer Apps Social

Company Picnic is a service-oriented company that focuses on providing solutions to enhance workplace culture and employee engagement. Their platform invites users to sign up for updates, indicating a commitment to keeping their audience informed and engaged.

Actual ComputerEnterprise Software

Actual Computer is building a system for inference that can coordinate real hardware as it exists, allowing for hosting GGUF models on local devices as well as across them, while striving to produce realtime tokens/second on everything from frontier-capable hardware to low-resource devices.

AthanorManufacturing Industrial

Athanor is building America's first vertically integrated manufacturer of specialty nitrogen derivatives, starting with creatine and scaling into pharma, defense, agriculture, semiconductors, and advanced materials.

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Research briefRead more
Worldbuild Research Overview Worldbuild is a thesis-driven venture capital firm founded and managed by Sumeet Singh, formerly a Partner at Andreessen Horowitz (a16z) and Senior Associate at Nyca Partners. The firm describes itself as partnering with "creative technologists" — founders who are building at the frontier of what AI and compute make possible. Worldbuild operates as a solo-GP fund based in New York. Investment Thesis: The Model Economy Sumeet Singh's investment framework, which he calls the "Model Economy," is grounded in one core observation: the playbook of the last era of software investing is over. Drawing on Richard Sutton's "bitter lesson" — the idea that scale and compute always beat domain-specific cleverness — Singh argues that most AI startups being built today are fighting a losing battle. Specialist tools that bolt AI onto existing workflows will be absorbed by increasingly capable foundation models over time. This leads Singh to two investment categories where he believes durable companies can be built: Path 1: Model Economy Infrastructure — Companies that build what AI models need to grow: compute marketplaces, data infrastructure, energy systems, networking layers, and security. These companies sell to AI labs and infrastructure providers directly. Examples in the portfolio include The San Francisco Compute Company (AI compute marketplace), Aetherflux (space-based solar power for AI data centers), Fractal Power (grid-scale energy infrastructure), and Flower Computer (humanist data and networking infrastructure). Path 2: Post-Skeuomorphic Applications — Companies that invent entirely new workflows that only become possible because of AI — not digitizing old processes, but discovering genuinely novel ones. These companies leverage multi-agent coordination, large-scale simulation, and continuous learning in ways that would be impossible without modern AI. Portfolio examples include Browserbase (headless browser infrastructure for AI agents), Armory Medical (agentic AI for healthcare operations), and Company Picnic (AI-powered living characters for interactive storytelling). Worldbuild explicitly avoids companies that simply wrap AI models around existing SaaS workflows — what Singh calls "the specialist trap." Stage Focus Worldbuild invests primarily at the pre-seed and seed stages, typically writing one of the first institutional checks into a company. The portfolio reflects very early-stage bets on technical founders before products reach market. Check Size Not publicly disclosed. Given the stage focus (pre-seed/seed) and solo-GP structure, typical check sizes are estimated in the $250K–$2M range. Lead Tendency Insufficient public data to confirm. Given the early-stage focus and the fact that Singh is often the first institutional investor, it is likely he leads or co-leads rounds. Portfolio Highlights The San Francisco Compute Company (sfcompute.com) : AI compute marketplace described as the "Airbnb" of GPU compute. Raised $40M Series A led by DCVC and Wing Venture Capital at $300M valuation. Browserbase (browserbase.com) : Reliable headless browser infrastructure for AI agents and LLMs. $68M total raised; $40M Series B led by Notable Capital. Aetherflux (aetherflux.com) : Space-based solar power startup founded by Baiju Bhatt (Robinhood co-founder). $50M Series A in April 2025 co-led by Index Ventures and Interlagos. Reportedly raising Series B at $2B valuation. Fractal Power (fractalpower.com) : Vertically integrated grid-scale energy company operating on the ERCOT grid in Austin, TX. Raised $7M. Builds, owns, and trades distributed energy assets. Armory Medical (armorymedical.com) : Applied AI lab building multi-modal orchestration and agentic AI systems to automate healthcare operations for clinics and enterprises. Company Picnic (companypicnic.com) : Builds AI-powered "Living Characters" with independent cognition and natural interaction. Team has backgrounds from Google, Pixar, Blizzard, and Netflix; award-winning (Oscar, Emmy, Arrow). Flower Computer (flowercomputer.com) : Building foundational data and networking infrastructure "from first principles" for a world where humans and machines interact naturally. Actual Computer (actual.inc) : Early-stage; details limited. Athanor (athanor.inc) : Early-stage; details limited. Truffle (itsalltruffles.com) : Early-stage developer tools. Interfere (interfere.com) : Early-stage; website restricted. Team Sumeet Singh — Founder and Managing Partner. Previously Partner at Andreessen Horowitz (a16z), where he invested in companies including Sardine (fraud detection, raised at 10x entry valuation at Series C). Prior to a16z, he was Senior Associate at Nyca Partners (fintech-focused VC) and worked at Brigit. Singh writes prolifically about AI infrastructure and the post-software era on his Substack (sumeetsingh.substack.com) and on Every.to. Investment Philosophy Sumeet Singh's three-step research process: (1) curate a high-quality information ecosystem through algorithm optimization and primary sources, (2) identify technological catalysts that enable new possibilities, and (3) convert research into conviction by generating hypotheses about which products and business models will emerge. He emphasizes that companies must either build what models need to get better, or invent workflows that only AI makes possible — anything in between is a trap. Geographic Focus Primarily US, with concentration in San Francisco Bay Area and New York. Portfolio companies are based in SF (sfcompute, Browserbase), San Carlos CA (Aetherflux), Austin TX (Fractal Power), Brooklyn NY (Flower Computer), and other US cities. Recent Activity Worldbuild has been actively investing across AI infrastructure and post-skeuomorphic applications from approximately 2023–2026. Multiple portfolio companies have achieved significant milestones: Browserbase raised $40M Series B (2025), Aetherflux raised $50M Series A (April 2025) and is reportedly raising a $2B valuation Series B (2026), and SF Compute raised $40M Series A.

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