Y Combinator Summer 2021 (S21) Companies

Union54 operates ChitChat, a messaging and payments application that combines encrypted messaging with USD card issuance and international fund transfers for users in Africa. The platform addresses high remittance costs by offering lower-fee cross-border payment capabilities for consumers and small businesses.

3 investors

V-Flow Medical develops medical devices intended to address the underlying causes of chronic pelvic pain in women, aiming to reduce opioid dependence and improve patient quality of life.

1 investor

Varos uses AI agents to automate business analysis work by conducting micro-interviews with employees to extract knowledge and generate decision-ready outputs like roadmaps and process optimization. The company serves enterprises seeking faster and more cost-effective business intelligence and analysis.

4 investors

VedaBio develops a molecular detection platform using CRISPR technology that enables rapid, accurate detection of multiple biological targets without the need for amplification. The platform serves research, diagnostics, and industrial applications across multiple markets.

3 investors

Verano Health operates an SMS-based telehealth platform that connects Medicaid patients with chronic diseases—particularly diabetes—to remote coaches for weekly check-ins and health education. The nonprofit targets underserved Americans who lack access to in-home disease management support.

1 investor

Verde provides digital lending services and loan origination tools to small and medium-sized farmers in Brazil, working through agricultural loan advisors.

1 investor

Verihubs is an AI-powered identity verification and risk decision platform that helps businesses verify identities, reduce fraud, and enable secure digital onboarding. The platform serves companies across multiple industries, with particular strength in Indonesia.

1 investor

Vibe Kanban is a project management platform designed for teams working with AI coding agents, enabling parallel agent workflows and human review of AI-generated code. It provides tools for organizing work, managing multiple coding agents simultaneously, and reviewing automated code changes.

1 investor

Vincoed manages educational programs and training across multiple institutions for organizations and their employees, offering services including preferential pricing, scholarship administration, coaching, and centralized payment processing.

4 investors

VitalStrata provides AI software to help managed care organizations improve the accuracy of risk adjustment coding and documentation, making their operations more resistant to audit scrutiny.

1 investor

Vogent is a platform for building AI voice agents that can handle phone calls, powered by custom conversational models and text-to-speech technology. It serves organizations across industries including healthcare and customer support, offering no-code agent building, call routing, and post-call automation.

3 investors

Wabi provides a no-code platform for content creators and coaches in Latin America to build branded websites, manage online programs, and process payments in a single integrated system.

2 investors

WarpBuild provides continuous integration and development infrastructure tools that speed up code building, iteration, and deployment for engineering teams.

1 investor

Warpfy builds a technology-led platform and ecosystem to help Indian and Asian brands expand into global B2C markets. The company operates four integrated platforms including an innovation lab, B2B wholesale distribution channel, brand partnership program, and learning community.

1 investor

Warrant provides an authorization service that developers use to implement access control policies in their applications, offloading permission logic to a dedicated platform so engineering teams can concentrate on product development.

1 investor

Waterplan provides a platform that assesses water risk for industrial and consumer goods companies by combining operational data with satellite imagery, then recommends mitigation strategies ranging from infrastructure upgrades to ecosystem-based approaches.

8 investors

Whalesync enables two-way data synchronization between spreadsheet tools (Google Sheets, Airtable, Notion) and vertical SaaS applications (Webflow, Salesforce, HubSpot, Affinity), allowing teams to automate bulk data operations across platforms without manual CSV imports.

3 investors

Whaly provides a data platform with enterprise-grade security and governance features for sales teams and data operations. The platform enables organizations to centralize data, manage access controls, and automate compliance while serving mid-to-large enterprises across industries.

1 investor

Writesonic is a platform for growth teams to monitor brand visibility across AI search engines (ChatGPT, Perplexity, Claude, Gemini) and take automated action through content creation, citation outreach, and technical fixes to improve AI search visibility and pipeline impact.

4 investors

Yemaachi creates a diverse cancer bio-database to develop oncology drugs effective across diverse patient populations. The company develops precision oncology research, diagnostics, and therapeutics with a focus on inclusion for global communities.

3 investors

Yummy is a Latin American super app that offers delivery services across multiple categories including food, groceries, transport, pharmacy, beverages, fashion, electronics, and events. The platform serves both consumers seeking delivery and merchants looking to expand their reach through a unified marketplace.

6 investors

Zage lets users make payments through bank transfers while accumulating rewards for their transactions.

2 investors

Zazos is a platform for enterprise operations that unifies business data and uses AI to extend or create missing capabilities, replacing legacy systems. It offers pre-built applications for expenses, time off, and evaluations alongside custom app creation through natural language, with built-in governance and audit trails.

2 investors

Zeit Medical develops a wearable headband with AI-powered sensors that detects strokes in real time and automatically alerts emergency services, targeting patients at high risk for stroke who may be asleep or unable to call for help themselves.

2 investors