Lab Intern, Chemistry & Lab Automation

About b12

b12 builds AI agents and automated laboratories that turn molecular designs into real compounds and experimental data. We recently launched b12 Foundry and are building out our lab operations in San Francisco.

We are looking for a hands-on scientist to help run the chemistry and make our experimental workflows reliable. You will work closely with the founders, scientists and engineers, taking experiments from a proposed protocol through execution, analysis and a clear record of what happened.

What you will do
• Plan and execute small-molecule synthesis and reaction-screening experiments.
• Prepare reagents, stock solutions, samples and plate layouts with careful attention to identity, concentration and traceability.
• Develop and run automated workflows, checking that the physical experiment matches the intended protocol.
• Troubleshoot dispensing, handling and instrument problems using observations, controls and run data.
• Analyze results, investigate unexpected outcomes and distinguish chemistry failures from execution failures.
• Maintain clear experimental records, QC checks and reproducible operating procedures.
• Help set up lab equipment, supplies and day-to-day workflows as we build our San Francisco operation.
• Work with our engineers to improve the tools that plan experiments and control laboratory instruments.

What we are looking for
• Strong hands-on laboratory experience in organic chemistry, chemical biology or a closely related field.
• Evidence that you can independently execute experiments, interpret results and troubleshoot when things do not work.
• Experience with analytical characterization and careful experimental documentation.
• Good judgment around chemical handling, laboratory safety, contamination and data quality.
• A practical, organized approach and willingness to take ownership of both the science and the work needed to keep the lab running.
• Ability to work full-time on-site in San Francisco, ideally starting soon.

Especially useful
• High-throughput experimentation, parallel synthesis or reaction optimization.
• Experience with Chemspeed, Opentrons, Hamilton, Tecan or other laboratory automation systems.
• LC-MS, HPLC, NMR or other relevant analytical methods.
• Python, instrument scripting or experience translating manual procedures into automated workflows.

You do not need experience with every instrument we use. We care about the experiments you have personally owned, how you diagnose problems and how quickly you learn.

The founding team

b12 Labs was founded by Zlatko Jončev and Andres M. Bran.

Zlatko brings deep experience in organic synthesis, catalysis, medicinal chemistry, and laboratory automation. Andres builds AI agents for chemistry and systems that translate scientific intent into executable laboratory workflows.

Between us, we have worked at Roche, Chemspeed, the Max Planck Institute, and EPFL, where we helped pioneer AI agents for chemistry and retrosynthesis.

We started B12 after repeatedly seeing the same problem: scientists had powerful instruments and increasingly capable AI models, but fragmented software still forced them to connect every step manually—or become programmers just to operate their laboratories.

We are building the unified software layer we wished existed: from synthesis planning and experiment design through robotic execution.

How to apply
Send your CV and a short description of an experiment or laboratory workflow you personally ran and improved. Tell us which instruments you operated or programmed, where you are currently based and your earliest on-site start date.