Y Combinator Winter 2023 (W23) Companies

Pylon provides post-sales workflow management tools designed for B2B teams operating across multiple communication platforms including email and chat. The platform enables teams to manage complex accounts and coordinate conversations among multiple stakeholders.

5 investors

Radical Aero builds StratoSats, autonomous solar-powered aircraft that operate at 65,000 feet for extended periods to deliver persistent high-performance infrastructure. The company develops stratospheric platforms for communication and data services.

3 investors

Rainmaker provides a cryptocurrency wallet using account abstraction technology that allows users to open accounts via email, fund them directly from traditional banking sources, and participate in decentralized finance without paying blockchain transaction fees.

2 investors

Rally Tax offers an AI-powered platform combined with human tax specialists to provide year-round tax strategy and filing for individuals with complex returns from investments, property, or self-employment. The service aims to reduce manual tax preparation work and identify savings opportunities beyond seasonal filing.

1 investor

Reflex is a platform for building and deploying enterprise applications in Python, combining framework, infrastructure, and data connectivity in a single unified system. It enables teams to develop, deploy, and manage production applications without fragmented tooling or multiple specialized roles.

4 investors

Relace builds specialized small language models and infrastructure for coding tasks including retrieval, merging, and code generation, serving software development teams looking to accelerate development and reduce errors in engineering workflows.

2 investors

Repacket builds security software that detects and prevents employee mistakes in real time. The product is positioned as an AI-powered secure web gateway for enterprise security teams.

1 investor

Resend provides an email sending platform for developers to build and send modern email templates that reach the inbox reliably. The platform addresses the technical challenges of email delivery across different email clients.

2 investors

Retape AI builds an AI-native CRM platform for debt settlement operations that automates repetitive, structured workflows while keeping humans in control of judgment and client relationships. The platform uses AI workers to manage settlement automation, data matching, and operational tasks across multiple systems.

1 investor

Rex.Fit makes a wearable camera device that uses computer vision to automatically track food intake and nutrition, alongside an API that fitness facilities integrate for nutritional analysis.

1 investor

Rift provides a platform for B2B sales teams to manage inbound leads from initial capture through booking and follow-up, combining form collection, lead qualification, rep assignment, calendar scheduling, and automatic re-engagement of no-shows.

1 investor

Rivet provides infrastructure for AI agents and realtime applications, offering stateful compute primitives called Actors that run in Node.js or Bun backends. The platform supports deployment options ranging from local libraries to fully managed cloud services or self-hosted environments with compliance features like air-gapped and on-premises support.

1 investor

Rollstack automates financial reporting cycles for finance teams, eliminating manual reporting work to free capacity for higher-value analysis and business activities.

2 investors

Rubber Ducky Labs provides AI-based product catalog analysis for e-commerce teams, automatically generating metadata tags from uploaded product data to improve search and discovery capabilities.

1 investor

Rubbrband is a video production agency that creates advertisements for emerging brands, leveraging Hollywood-level production expertise.

3 investors

Ruby Card provides banking services and spend management tools specifically designed for e-commerce retailers, integrating directly with commerce platforms to give businesses visibility into their finances and cash flow.

1 investor

RUUF is a solar panel installation and energy service company serving residential customers in Chile. The company handles the full process from evaluation and design to installation, certification, connection, and ongoing monitoring.

1 investor

Sage AI automatically generates and maintains documentation for codebases by building a symbol-level knowledge graph from source code and using large language models to create and update annotations. The platform serves software engineering teams seeking to reduce onboarding time, improve code comprehension, and preserve institutional knowledge.

1 investor

Salient builds AI agents for consumer finance operations, specifically for collections, servicing, and claims processing at lenders and financial service providers. The company's platform automates customer interactions and administrative workflows with regulatory compliance built in.

2 investors

Sameday provides AI voice systems that answer incoming calls and handle overflow/after-hours service for plumbing and HVAC businesses. The system uses AI models to manage customer interactions and scheduling.

1 investor

Sanvivo is an API-driven platform that connects local pharmacies in Germany with digital business models. The platform enables pharmacies to participate in online markets and streamline operations without requiring marketing, IT expertise, or operational overhead.

2 investors

Scanbase designs and implements tailored algorithm solutions for medical diagnostic companies to optimize diagnostic workflows, improve product quality, and reduce costs. The company serves healthcare organizations by providing expert engineering support for diagnostic interpretation algorithms.

3 investors

Scout produces personalized audio news summaries in podcast format, delivering industry and interest-based updates to users during commutes and exercise.

1 investor

Second provides automated codebase maintenance and analysis tools for engineering teams, covering tasks like code migrations and intelligent code insights.

1 investor