CareersFounding team opportunities

Build for what people will invent.

We want intelligence to develop in many places, through the knowledge and ambitions of people and organizations. We are building a foundation for that future with on-device language and voice models connected to frontier intelligence.

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SADAIR / Founding team

We are looking for people who can move between first principles and finished work.

Find your part in the work.

Our work spans model research, on-device systems, developer tools, and interaction design. We value depth in a field and the curiosity to follow a problem beyond it. All roles are full-time, based in San Francisco or remote.

Research Engineer, Language Models

Team
Model Research
Location
San Francisco or remote
Employment
Full-time

You will develop our Personal Language Model family, investigating how much useful capability can fit into the devices people use every day. Your work will connect model architecture, training data, and learning objectives with reasoning, tool use, and conversation. You will work with systems engineers to carry promising experiments through to models that perform well under real deployment constraints.

What you will do

  • Design pre-training or post-training experiments that improve capability, context use, and computational efficiency.
  • Build data preparation and training pipelines, and investigate how data quality and sampling affect model behavior.
  • Develop evaluations for instruction following, reasoning, tool use, and multi-turn tasks, including cases where aggregate scores conceal failures.
  • Use controlled experiments and ablations to distinguish reproducible improvements from noise or changes in evaluation conditions.
  • Work with inference engineers to understand how compression and quantization affect the capabilities you train.
  • Document findings and turn successful experiments into checkpoints, evaluation tools, and methods others can build on.

What we are looking for

  • Strong Python skills and practical experience with PyTorch or a comparable deep-learning framework.
  • Experience training, adapting, or deeply investigating language models, with work you can discuss in detail.
  • A solid understanding of optimization, model architectures, and experimental design.
  • The ability to debug research code, investigate unexpected results, and explain the evidence behind a decision.
  • Careful engineering habits and the willingness to work across model research and deployment.

Additional experience we value

  • Experience with distributed training, data quality, distillation, or model compression.
  • Research on long-context modeling, preference learning, or adaptation to particular tasks and users.
Apply for this role

ML Systems Engineer, On-Device Inference

Team
Model Systems
Location
San Francisco or remote
Employment
Full-time

You will build the inference systems that make our language and voice models practical on phones, personal computers, and other devices. The work begins with understanding where time, memory, and energy go, then changing the execution path. You will help model researchers make architectural choices that translate into responsive, sustained performance on real hardware.

What you will do

  • Profile model loading, prefill, decoding, and streaming output across Apple and Android devices and desktop hardware.
  • Optimize kernels, execution graphs, memory allocation, and cache management for target processors.
  • Develop mixed-precision and quantized execution paths, checking numerical correctness and model quality alongside performance.
  • Measure sustained behavior under realistic context lengths, concurrent workloads, and thermal conditions.
  • Build repeatable benchmarks and regression tests for latency, memory, energy use, and reliability.
  • Collaborate on model and runtime design, and package improvements into maintainable interfaces other engineers can use.

What we are looking for

  • Strong systems programming skills in C++, Rust, or a comparable language, with Python for experimentation and tooling.
  • An understanding of transformer inference, memory hierarchies, and the factors that limit compute or bandwidth utilization.
  • Experience with inference runtimes, hardware acceleration, or deploying machine-learning models on constrained hardware.
  • The ability to use profilers and measurements to explain a bottleneck and verify an improvement.
  • Careful debugging and testing habits, including attention to numerical changes and performance regressions.

Additional experience we value

  • Experience with Metal, MLX, Core ML, CUDA, or mobile GPU and NPU execution.
  • Work on low-bit quantization, custom kernels, compiler optimizations, or streaming audio systems.
Apply for this role

Research Engineer, Speech

Team
Voice Research
Location
San Francisco or remote
Employment
Full-time

You will develop KRORAINA 2, our voice models for contextual speech and full-duplex conversation. The research spans how speech sounds and how a system takes part in an exchange, including pauses, overlap, interruptions, and changes of direction. You will work with model and inference engineers to make those behaviors useful in continuous, on-device interaction.

What you will do

  • Design and train models for speech generation, audio representation, or conversational behavior, drawing on your area of expertise.
  • Build audio data pipelines for cleaning, segmentation, alignment, and quality assessment.
  • Investigate how dialogue history shapes prosody, delivery, and consistency across turns.
  • Develop turn-taking, backchannel, and interruption behavior, including recovery when a person continues or changes their request.
  • Combine listening studies with objective evaluations of intelligibility, voice quality, timing, and interaction failures.
  • Improve streaming generation with systems engineers, measuring responsiveness and quality together on target devices.

What we are looking for

  • Strong Python skills and hands-on experience with a modern deep-learning framework.
  • Depth in at least one area of speech or audio modeling, such as synthesis, recognition, audio representations, or speech-to-speech systems.
  • Experience preparing audio data and designing experiments that reveal why a model succeeds or fails.
  • The ability to connect model training with inference, evaluation, and an interactive prototype.
  • Attentive listening and clear technical judgment about differences conventional benchmarks may miss.

Additional experience we value

  • Experience with streaming architectures, neural audio codecs, waveform generation, or full-duplex systems.
  • Work on multilingual speech, expressive synthesis, human preference studies, or low-latency deployment.
Apply for this role

Software Engineer, Developer Platform

Team
Developer Platform
Location
San Francisco or remote
Employment
Full-time

You will build the developer platform and Agent SDK that let others combine SADAIR’s language and voice models, tools, and frontier model access in their own applications. Your work spans the interfaces developers write against and the execution systems underneath. You will make continuous interactions across local and remote models easier to build, test, and maintain.

What you will do

  • Design APIs and SDKs for model calls, streaming, tool use, and session control, with clear behavior and useful errors.
  • Build agent execution across on-device models and frontier services, including cancellation, retries, recovery, and handoffs.
  • Define how applications connect tools and data sources, keeping access permissions explicit and enforceable.
  • Develop tracing, evaluation hooks, and tests that help developers investigate failures as models and integrations change.
  • Maintain releases, compatibility, documentation, and working examples so developers can adopt new capabilities with confidence.
  • Work with model and systems engineers to improve latency and resource use throughout the application.

What we are looking for

  • Experience shipping and maintaining developer tools, APIs, SDKs, or infrastructure used by other engineers.
  • Strong programming skills in Python or TypeScript, with the ability to work across unfamiliar components.
  • A sound understanding of asynchronous execution, API contracts, testing, and common network and process failures.
  • The ability to turn an unclear developer need into a usable interface and explain the tradeoffs behind it.
  • Careful judgment around permissions, sensitive data, and the consequences of tool execution.

Additional experience we value

  • Experience with agent frameworks, persistent sessions, or on-device runtime integration.
  • Work on open-source libraries, developer documentation, or versioned public APIs.
Apply for this role

Product Designer, AI Interaction

Team
Product Design
Location
San Francisco or remote
Employment
Full-time

You will shape how people work with SADAIR’s intelligence across conversational products and developer tools. Your work will connect product structure, interaction behavior, and visual craft. Working with researchers and engineers, you will make ongoing AI work understandable and give people clear ways to guide it as they speak, explore, and act.

What you will do

  • Study how people and organizations approach real tasks, and identify where AI can support their judgment and invention.
  • Develop product concepts, task flows, and interactive prototypes, then test them with the people who would use them.
  • Design how people follow ongoing work, interrupt speech, correct an interpretation, and approve or stop an action.
  • Make system limits and choices understandable when they affect privacy, control, or a person’s ability to complete a task.
  • Develop shared interaction patterns and components, carrying accessibility and visual consistency across devices.
  • Work with engineers through implementation, inspect the finished interactions, and refine the experience using observed behavior.

What we are looking for

  • A portfolio of product work that explains the problem, your contribution, and how the design developed through implementation.
  • Strong interaction design, information architecture, and visual craft.
  • Experience learning directly from users and turning observations into product decisions.
  • The ability to prototype behaviors that unfold over time, including waiting, interruption, errors, and recovery.
  • Clear communication and the curiosity to understand how technical choices affect the experience you are designing.

Additional experience we value

  • Experience designing voice, multimodal, or other interactions that extend beyond a conventional screen.
  • Interactive prototyping in code, or work on AI products, developer tools, and complex workflows.
Apply for this role

How we work

Take the idea all the way.

  • Start with what should be possible.

    Ask what people could do with a better foundation, then work back to the models and systems it requires. Revisit the assumptions that make a problem look settled.

  • Follow the problem across boundaries.

    In our small team, researchers, engineers, and designers work closely together. A training decision can change an interaction. A problem on a device can send us back to the research. Stay with those connections until the idea works in use.

  • Let evidence change the plan.

    Make an idea testable. Explain what the results show, invite disagreement, and revise the approach when a better explanation emerges. Clear writing helps the whole team think further.

  • Build so others can go further.

    Finish the experiment, interface, and documentation that make work useful beyond its author. Take responsibility for how it behaves and for the people who will depend on it.

Open application

Tell us what only you can bring.

Send a concise note about the problem you want to solve, the work that best represents you and why SADAIR is the place to do it.

Introduce yourself