Full-Time

Senior Principal AI Engineer

Posted on 9/11/2026

Unusual Ventures

Unusual Ventures

11-50 employees

Invests in early-stage tech startups

No salary listed

Boston, MA, USA

In Person

Category
Software Engineering (1)
Required Skills
LLM
Python
React.js
Graph Databases
Machine Learning
RAG
TypeScript
Go
Data Modeling

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Requirements
  • At least 12 years of software engineering experience, including deep hands-on experience building artificial intelligence and machine learning systems in production.
  • Strong proficiency in TypeScript, React, Go, Python, and modern artificial intelligence frameworks.
  • Extensive experience with large language models, including retrieval-augmented generation, tool use, prompt systems, and agentic architectures.
  • Ability to design and ship large-scale artificial intelligence systems that run reliably in real-world environments.
  • Strong architectural judgment across data systems, artificial intelligence models, infrastructure, and application layers.
  • Deep understanding of artificial intelligence failure modes, including hallucination, drift, brittleness, latency, and cost increases.
  • Ability to explain technical tradeoffs to technical and non-technical audiences.
  • Track record of shipping systems end-to-end rather than only prototypes or research work.
Responsibilities
  • Architect and build end-to-end artificial intelligence systems, including large language model orchestration, retrieval layers, agentic workflows, and structured reasoning systems.
  • Lead the design of multi-agent and tool-calling systems that operate reliably in production.
  • Establish and evolve architecture patterns for scalable, cost-aware, and observable artificial intelligence applications.
  • Drive technical decisions across data modeling, artificial intelligence pipelines, infrastructure, and application programming interfaces.
  • Define best practices for evaluation, monitoring, and governance of artificial intelligence systems in production.
  • Mentor senior engineers through design reviews, code reviews, and system-level debugging.
  • Translate ambiguous business and domain problems into clear technical strategies.
  • Integrate relevant emerging artificial intelligence techniques into production systems.
  • Build systems from initial drafts through iteration and production, surfacing real constraints early.
  • Help the organization remain in builder mode as it grows, reduce unnecessary complexity, and determine when architectural rigor is appropriate.
  • Pull promising work across the finish line and model speed, ownership, and clarity for other senior engineers.
Desired Qualifications
  • Knowledge of knowledge graph architecture, ontology design, or semantic modeling in complex domains.
  • Experience with graph databases, graph query languages, or graph machine learning techniques.
  • Experience building hybrid systems that combine structured reasoning with large-language-model-based approaches.
  • Experience with entity resolution, schema alignment, or knowledge fusion at scale.
  • Experience building artificial intelligence systems requiring explainability, auditability, or lineage tracking.
  • Experience building artificial intelligence systems in regulated or high-stakes domains such as finance, healthcare, legal, or government.
  • Experience with machine learning operations, evaluation infrastructure, or long-running artificial intelligence services operating at scale.

Unusual Ventures is a venture-capital firm that backs early-stage tech startups and helps them reach product-market fit. It combines financial investment with practical support, offering portfolio companies access to a Field Guide—a library of more than 100 articles, case studies, interviews, and tools designed to guide founders through building and growing a business. The company earns returns by taking equity stakes in its investments and helping portfolio companies grow value. Its differentiator is the integrated mix of capital with structured, tactical resources and guidance that goes beyond standard funding, specifically aimed at accelerating product-market fit and business growth for startups.

Company Size

11-50

Company Stage

N/A

Total Funding

$2.9B

Headquarters

Menlo Park, California

Founded

2018

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Simplify Jobs

Simplify's Take

What believers are saying

  • August 26, 2026 Oliver AI deal proves Unusual still wins early AI infrastructure rounds.
  • July 15, 2026 Rime and April 2, 2026 Miravoice show repeat momentum in voice AI.
  • March 12, 2026 Qdrant and January 26, 2026 Railway signal strong enterprise follow-on conviction.

What critics are saying

  • By 2027, AI seed competition from Menlo, Sequoia, and a16z erases sourcing advantages.
  • Unusual's portfolio tilts toward crowded AI infrastructure, compressing ownership and exit multiples.
  • No breakout IPO or blockbuster exit in 2026 leaves the fund dependent on paper marks.

What makes Unusual Ventures unique

  • Unusual's Field Guide offers 100-plus tactical resources for founders seeking product-market fit.
  • Partnered seed investing and founder services make Unusual an operator-heavy first-check investor.
  • 2026 portfolio activity spans Rime, Miravoice, Qdrant, Railway, and Oliver AI.

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Benefits

Stock Options

Remote Work Options

Company News

PR Newswire
Aug 26th, 2026
Menlo and Unusual Ventures back Oliver AI's database built for agentic AI workloads

OliverAI has secured pre-seed funding from Menlo Ventures and Unusual Ventures to scale OliverDB, its analytical data platform built for agentic AI. The San Francisco-based company addresses a bottleneck in enterprise AI infrastructure: existing analytics systems weren't designed for the continuous, machine-speed workloads that AI agents generate. OliverDB's analytical engine processes queries significantly faster than existing systems whilst using less compute power. In internal tests using ClickBench benchmarks, Oliver ran hundreds of times faster than ClickHouse on CPUs and thousands of times faster with GPU execution. The platform includes governance features allowing enterprises to control agent access to data and systems whilst maintaining records of all interactions. OliverDB is available today as a managed service or for deployment within customer VPCs.

Rime
Jul 16th, 2026
Rime

For the first time in human history, a rich understanding of language is available as a utility, delivered via API, useful enough to “be metered”. Intelligence has become a tool: something you can call, compose, and build on, divorced from any individual human mind.

Silicon Valley Daily
Jul 16th, 2026
Rime reels in $24 million.

Rime reels in $24 million. SAN FRANCISCO - Rime, an enterprise voice AI platform, has reeled in $24 million in Series A funding led by M13, with participation from Twilio Ventures, Corazon Capital, and continued participation from Unusual Ventures and other existing investors. Morgan Blumberg, Partner at M13, will join Rime's Board of Directors. The funds will be used to invest in Rime's proprietary conversational dataset and make strategic hires in engineering and research as the company scales its infrastructure. Rime also announced the appointment of Rafael Valle as Chief Science Officer. Valle, who previously led audio research at Meta's Super Intelligence Lab, joins Rime to accelerate the company's research and product innovation. Discover more Personal Aircraft Machine Learning & Artificial Intelligence Engineering & Technology Voice is the last interface computers are still bad at. While many voice AI companies chase generic signals of naturalness, Rime takes a linguistics-first approach. Founded by Lily Clifford (while pursuing a Stanford linguistics PhD), Brooke Larson (PhD linguist, ex-Amazon Alexa), and Ares Geovanis (Stanford engineer), Rime blends academic speech science with one of the world's largest collections of expressive multilingual conversational speech. The bet is that the company defining this next interface won't be the one with the biggest model, it will be the one that can measure what good actually sounds like, and design toward it. "The things that matter most in conversation are the hardest to pin down. Response relevance is hard to specify; speech appropriateness is hard to verify. There's no unit test for sounding like you care," said Lily Clifford, co-founder and CEO of Rime. "That's exactly why this is a design problem, not just an engineering one. We're building voice interaction models, systems where our linguistic judgment and taste become research instruments, not afterthoughts. With this new funding and Rafael Valle joining as Chief Science Officer, we're 10x-ing our data investment to define the design language of conversational general intelligence." Today, Rime powers nearly 100 million phone calls monthly for companies like Mayo Clinic, Dialpad, Upstart, and Asurion. By staying focused strictly on the modeling layer and their linguistics roots, the platform has gained significant traction in healthcare and financial services, where pronunciation accuracy for complex terminology and HIPAA compliance are critical. "In financial services, the stakes for voice AI are exceptionally high and accuracy is a requirement for customer trust," said Shiv Indap, Upstart. "Rime's ability to handle complex financial use cases with precision allows us to build experiences that truly serve our customer's needs." The efficacy of Rime's approach was recently validated by an independent study conducted by Miravoice, which evaluated 12 voices from three vendors, across 100,000 calls, finding that Rime's voices resulted in statistically significantly lower "Hung Up During Intro" (HUDI) rates compared to major competitors. Rime also demonstrated the fastest median time to completion among all providers tested, proving that linguistic nuances like cadence and speed drive measurable business results. Rime voices keep more customers on the line longer. Discover more Time & Calendars Business Formation Business & Corporate Law "The design patterns that will define the speech-to-speech era of AI haven't been built yet. Rime is doing the foundational work by combining frontier AI with deep linguistic expertise to create the speech infrastructure the next generation of AI products will rely on," said Morgan Blumberg, Partner at M13. "Lily, Ares and Brooke are building Rime with the rare combination of world-class AI research and deep linguistic expertise to deploy real time voice people can trust in complex, regulated environments."

FinSMEs
Jul 15th, 2026
Rime Raises $24M in Series A Funding

Rime, a San Francisco, CA-based provider of an enterprise voice AI platform, raised 24M in Series A funding

TechCrunch
Jul 15th, 2026
Rime picks up $24M Series A to help enterprises field customer calls | TechCrunch

Rime is handling over 100 million calls each month across multiple companies.