Fundraising Fox
Riften
YC S26San Francisco, US · Founded 2026 · 5 employees · 2 known investors
Find your way into Riften
Sign up to see every warm intro you have to Riften
- Paths you didn't know you had: your email and LinkedIn already hold routes to the Riften team. We find them for you
- 2nd- and 3rd-degree connections: the friend-of-a-friend routes that take hours to manually find through your inbox or LinkedIn
- Answers now, not in days: momentum is everything in a raise. Skip asking around whether someone knows someone
Days of research, done the moment you sign in, with every route ranked by how warm it is.
Riften provides a routing layer that sits between a company's applications and large language model APIs, directing each request to the least expensive capable model and using self-hosted open-weight models where possible to reduce inference costs. It also uses the resulting task data to train private, company-owned models on recurring work, serving businesses that run AI-powered applications.
AI & Machine LearningData & InfrastructureDeveloper ToolsEnterprise SoftwareReinforcement LearningOpen SourceInfrastructureAIUnited States of AmericaAmerica / Canada
Founders & leadership· Y Combinator alumni (S26)
Riften was founded in 2026 by Carl Stauffer.
CS
Carl StaufferFounderCarl Stauffer is the founder and CEO of Riften, which routes requests between applications and language model APIs to lower inference costs. He previously worked as a Forward Deployed Engineer at Palantir and as a nuclear researcher at Jefferson Lab, and studied computer science and applied mathematics at Johns Hopkins.
Investors · 2
Y Combinatorlisted by Y CombinatorSan Francisco · $500K
How we know: the Y Combinator directory · open dataset · 5k.vc investor directory · Not right? Tell us
Related companies · 5
UnifyUnify provides AI agents that handle routine business tasks across communications, sales, operations, and engineering by executing pre-built workflows or custom automation. The service serves tech-focused companies and teams looking to offload administrative and repetitive work.
Vibrant LabsVibrant Labs builds tools for teams to develop AI systems that function effectively in real-world applications. The company focuses on providing developer tooling for machine learning and AI implementation.
hiloophiloop provides snapshottable, forkable compute infrastructure with built-in observability for AI agents that propose, run, and verify experiments (autoresearch). It offers self-provisioning sandboxes via API, brokered secrets, and per-run tracing with token and cost tracking queryable via SQL, aimed at teams doing autoresearch, model training, and performance-critical development.
MonteMonte builds post-training and continual learning infrastructure that transforms general AI models into specialized agents adapted to specific organizational workflows. The platform captures training signals from real work, measures performance against actual constraints, and enables reinforcement learning so models improve continuously from experience.
Experiential LabsAn applied AI research lab that develops world models enabling agents to simulate physical environments with high-fidelity reconstruction, using technology derived from autonomous vehicle systems.
Companies working in the same space as Riften.
Legal entities · 1
corporate structureRiften Inc.
In the news
Frequently asked questions
- What does Riften do?
- Riften provides a routing layer that sits between a company's applications and large language model APIs, directing each request to the least expensive capable model and using self-hosted open-weight models where possible to reduce inference costs. It also uses the resulting task data to train private, company-owned models on recurring work, serving businesses that run AI-powered applications.
- Who founded Riften?
- Riften was founded by Carl Stauffer in 2026.
- Who are Riften's investors?
- Riften's investors include Vela Partners, Y Combinator.
- Where is Riften headquartered?
- Riften is headquartered in San Francisco, US.