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PBridge

Full-time jobsthe United States

Software Engineer, Payments Infrastructure

sierra · San Francisco, CA · Full-time

About this role

ABOUT US

At Sierra, we’re creating a platform to help businesses build better, more human customer experiences with AI. We are primarily an in-person company based in San Francisco, with growing offices in Atlanta, New York, London, Paris, Madrid, Munich, Singapore, Tokyo, and Sydney.

We are guided by a set of values that are at the core of our actions and define our culture: Trust, Customer Obsession, Craftsmanship, Intensity, and Family. These values are the foundation of our work, and we are committed to upholding them in everything we do.

Our co-founders are Bret Taylor https://www.linkedin.com/in/brettaylor/ and Clay Bavor https://www.linkedin.com/in/claybavor/. Bret currently serves as Board Chair of OpenAI. Previously, he was co-CEO of Salesforce (which had acquired the company he founded, Quip) and CTO of Facebook. Bret was also one of Google's earliest product managers and co-creator of Google Maps. Before founding Sierra, Clay spent 18 years at Google, where he most recently led Google Labs. Earlier, he started and led Google’s AR/VR effort, Project Starline, and Google Lens. Before that, Clay led the product and design teams for Google Workspace. 

WHAT YOU'LL DO

The Payments Infrastructure team builds the trust boundary between a live conversation and the rest of Sierra: sensitive data enters through a customer's voice or chat, leaves as a token, and the agent never sees the plaintext in between. Doing this well means weaving four hard domains together at once: LLMs, payments, infrastructure, and voice. Done right, it unlocks seamless, compliant payments for every Sierra agent and the people who use them. It's already one of the highest-containment features Sierra ships: when an agent can take a payment, the conversation keeps going instead of transferring to a person, so the agent resolves everything around it too. The platform is PCI DSS Level 1, on Visa's Global Registry, and carries cardholder data across millions of payment lifecycle events for enterprise customers.

- Design the secure-capture protocol every channel sits behind, so the payment feels like one continuous conversation to the person on the other end, while telephony providers, contact-center platforms, embedded chat, and Sierra's own voice stack all present a single event lifecycle to agent code, no matter how different each customer's stack is.

- Build and extend the tokenization platform: per-token envelope encryption with a unique data key per token, so a single compromised decrypt exposes one token at most.

- Own the security perimeter around the cardholder-data environment, so what each system can reach is enforced by infrastructure rather than convention, and auditable by design.

- Build deterministic, auditable detection in the agent's hot path that catches the cardholder data general-purpose models miss, and help design the purpose-built detection model that comes next. No LLM, including any we build ourselves, ever sees plaintext cardholder

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