Software Engineer, Payments Infrastructure

Job summary

Responsibilities

The agent must collect and use a card number but can never see it. This work sits across four hard technical domains: payments, security, real-time voice, and LLMs. Voice is the core challenge.

• Build real-time card capture for voice: intercept keypad and spoken digits in a live audio stream, upstream of the agent runtime in a network-segmented environment, while the LLM…
• Build and extend the tokenization platform: agents receive and send short-lived tokens, and the platform swaps a token for the real value only when it calls the customer's…
• Own the payments egress control plane: every destination for card data is approved, versioned with the agent release, and enforced by infrastructure below the application, not by…
• Make payment actions correct: an at-most-once action primitive in the Agent SDK, validated amounts and items, and monitoring that compares what the agent said about a payment…
• Keep card data out of places it should not be: deterministic detection in the agent's hot path that catches what general-purpose models miss.

What they're looking for

• 5+ years building backend, platform, or infrastructure systems, with a track record of shipping and operating high-reliability services in production.
• A deep security instinct. You design as though every component will eventually be compromised, and you reason naturally about blast radius, least privilege, and making bad states…
• Rigor about correctness under failure: retries, idempotency, at-most-once behavior, and clear handling of timeouts and unclear results from external systems.
• Fluency in a systems language (we use Go) and comfort owning critical systems end to end, from design through production and on-call.
• Range and ownership. You like a small team with broad scope, you build clean abstractions over messy external systems, and you're never satisfied solving a problem once per…

Tech stack

• Go