Senior Software Engineer, X-Scientist

Xairatherapeutics; South San Francisco (CA); On-site; USD 205,000 - 275,000; Full time

Job summary

Xaira Therapeutics is hiring on the X-Scientist team to build AI-powered systems that connect models, biology tools, and workflows. You will develop backend services, APIs, and developer tools to enable scientists to run analyses, inspect steps, and iterate results.

You will work at the crossroads of AI, software engineering, and therapeutic discovery, building reliable, scalable solutions for long-running, multi-step workflows in a dynamic biotech environment.

Qualifications

• Strong Python engineering fundamentals, with clean, typed, tested, maintainable code.
• Experience building at least one of: a production library, CLI, API, SDK, backend service, workflow system, or developer platform.
• Familiarity with LLM application development, agent frameworks, tool calling, MCP-style interfaces, or orchestration systems.
• Comfort working with complex systems that combine multiple components, external calls, domain-specific logic, and evolving user needs.
• Good instincts for abstraction, error handling, reliability, and designing software that can grow across use cases.
• Strong communication skills and ability to work in a collaborative, multidisciplinary environment.

Responsibilities

• Backend systems and APIs that connect AI models to scientific tools, datasets, and analysis workflows
• Tool-calling infrastructure, CLIs, SDKs, and workflow runners that scientists and ML researchers use day-to-day
• Agentic interfaces where users can run analyses, inspect intermediate steps, and iterate on results
• Observability and testing for long-running workflows that call external tools and produce scientific outputs
• Design reliable systems for long-running, multi-step workflows with strong testing, observability, logging, and maintainability.
• Collaborate with scientific and technical teams to turn complex research workflows into usable, extensible software.

Skills

Python

Backend systems

APIs

LLM applications

Orchestration systems

Testing

Tools

CLI

SDKs

API design

Workflow systems

Job description

About Xaira Therapeutics

Xaira is an innovative biotech startup focused on leveraging AI to transform drug discovery and development. The company is leading the development of generative AI models to design protein and antibody therapeutics, enabling the creation of medicines against historically hard-to-drug molecular targets. It is also developing foundation models for biology and disease to enable better target elucidation and patient stratification. Collectively, these technologies aim to continually enable the identification of novel therapies and to improve success in drug development. Xaira is headquartered in the San Francisco Bay Area, Seattle, and London.

About the Role

Xaira is pioneering an AI-native approach to discovering and developing the next generation of life-changing medicines. We are building predictive and agentic AI systems across drug discovery, and the X-Scientist team accelerates this mission by making AI-assisted science reliable, usable, and scalable across drug discovery workflows.

On the X-Scientist team, you will work at the intersection of AI, software engineering, and therapeutic discovery. You will collaborate closely with AI scientists, engineers, platform teams, and drug discovery experts to build systems that connect AI models, biological tools, datasets, and scientific workflows.

This role spans backend systems, APIs, tool-calling infrastructure, workflow orchestration, developer-facing SDKs and CLIs, and agentic interfaces that help scientists run analyses, inspect intermediate steps, and iterate on results.

What You'll Do

• Backend systems and APIs that connect AI models to scientific tools, datasets, and analysis workflows
• Tool-calling infrastructure, CLIs, SDKs, and workflow runners that scientists and ML researchers use day-to-day
• Agentic interfaces where users can run analyses, inspect intermediate steps, and iterate on results
• Observability and testing for long-running workflows that call external tools and produce scientific outputs
• Design reliable systems for long-running, multi-step workflows with strong testing, observability, logging, and maintainability.
• Collaborate with scientific and technical teams to turn complex research workflows into usable, extensible software.

What We're Looking For

• Strong Python engineering fundamentals, with clean, typed, tested, maintainable code.
• Experience building at least one of the following: a production library, CLI, API, SDK, backend service, workflow system, or developer platform.
• Familiarity with LLM application development, agent frameworks, tool calling, MCP-style interfaces, or orchestration systems.
• Comfort working with complex systems that combine multiple components, external calls, domain-specific logic, and evolving user needs.
• Good instincts for abstraction, error handling, reliability, and designing software that can grow across use cases.
• Strong communication skills and ability to work in a collaborative, multidisciplinary environment.

Nice to Have

• Background or interest in computational biology, bioinformatics, protein design, single-cell genomics, biomedical AI, or adjacent domains.
• Familiarity with biomedical databases or tools such as PubMed, UniProt, AlphaFold, PDB, DepMap, or related resources.
• Curiosity about biology and scientific research; you do not need a biology background, but you should be excited to learn the domain and work closely with scientists and ML researchers.

Compensation

We offer a competitive compensation and benefits package, seeking to provide an open, flexible, and friendly work environment to empower employees and provide them with a platform to develop their long-term careers. A Summary of Benefits is available for all applicants. We offer a competitive package that includes base salary, bonus, and equity. The base pay range for this position is expected to be $205,000 - $275,000 annually with a total cash compensation up to $235,000 - $325,000; however, the compensation offered may vary depending on the market, job-related knowledge, skills and capabilities, and experience.

Xaira Therapeutics is an equal-opportunity employer. We believe that our strength is in our differences. Our goal to build a diverse and inclusive team began on day one, and it will never end.

TO ALL RECRUITMENT AGENCIES: Xaira Therapeutics does not accept agency resumes. Please do not forward resumes to our jobs alias or employees. Xaira Therapeutics is not responsible for any fees related to unsolicited resumes.