Staff/Principal Software Engineer

Recruiting From Scratch•San Francisco, CA

1d•Hybrid

About The Position

Synthetic AI is building an autonomous AI system designed to fully replace traditional bookkeeping services for small and medium-sized businesses. The company is recreating the professional service of bookkeeping through AI, building autonomous agents capable of handling complex financial workflows end-to-end. Synthetic is developing a fully autonomous bookkeeping agent that can manage financial operations, integrate with financial providers, maintain accounting records, and continuously execute bookkeeping workflows without traditional human intervention. The company is a highly technical, extremely early-stage startup with a team of approximately five employees and approximately $10M in funding. The team is made up of experienced startup builders focused on moving quickly and building a category-defining AI product. As a Staff / Principal Software Engineer, you'll join the founding engineering team and have significant ownership over the architecture, product, AI systems, and financial infrastructure that powers Synthetic. This is a high-leverage engineering opportunity where you'll work across the full stack, AI agents, financial integrations, accounting infrastructure, and customer-facing product development.

Requirements

5+ years of professional software engineering experience
Strong experience building production software systems
Experience owning complex technical projects end-to-end
Experience working across both frontend and backend systems
Experience building AI-powered or AI-native products
Experience working with financial systems, fintech, accounting, or financial APIs preferred
Experience integrating third-party APIs and financial platforms
Experience working in early-stage or high-growth startups
Strong product engineering experience with significant ownership
Experience operating independently without extensive processes or management
Strong track record of shipping production features quickly
Experience working directly with customers or external partners preferred
Strong builder mentality and willingness to work across the entire product stack
Expert-level TypeScript experience
Strong Next.js and Node.js experience
Strong full-stack software engineering fundamentals
Experience building production backend systems
Experience building LLM-powered applications or AI agents
Experience integrating AI/ML capabilities into production products
Experience designing APIs and third-party integrations
Experience with financial APIs or fintech infrastructure preferred
Experience building financial data systems, ledgers, or accounting infrastructure preferred
Strong database and data modeling experience
Experience designing reliable production systems
Strong understanding of distributed systems and backend architecture
Experience with modern AI/LLM tooling
Experience building autonomous workflows or agentic systems
Strong software architecture and system design capabilities
Ability to write clean, maintainable production code
Experience with Node.js and modern JavaScript/TypeScript infrastructure
Experience working with LLMs, AI/ML systems, or agent orchestration preferred
Bachelor's degree or higher in Computer Science, Engineering, Mathematics, or related technical field preferred
Strong computer science and software engineering fundamentals
Equivalent practical engineering experience accepted
Strong technical depth in systems, backend engineering, AI, or financial infrastructure preferred
Exceptional engineering ownership
Extremely high execution velocity
Strong product intuition
Excellent problem-solving ability
Comfortable operating independently
Comfortable working without extensive direction
Strong customer empathy
Excellent communication skills
Comfortable speaking directly with customers and integration partners
Strong startup mentality
Bias toward action
Willingness to work across frontend, backend, AI, and infrastructure
Comfortable with rapidly changing priorities
Strong technical judgment
Low-ego collaborative mentality
Passion for building AI-native products
Comfortable working in an extremely small engineering organization
Willingness to operate at high intensity

Responsibilities

Build and enhance AI agents capable of autonomously handling end-to-end bookkeeping workflows
Develop AI-powered systems that automate complex financial operations for SMB customers
Own financial provider integrations with platforms such as Ramp, Brex, and Gusto
Take financial integrations from initial scoping through production deployment
Design and build the company's accounting ledger from the ground up
Architect core financial data infrastructure supporting bookkeeping workflows
Build reliable systems for financial data ingestion, processing, reconciliation, and reporting
Ship new product features rapidly across the full stack using TypeScript and Next.js
Work across frontend and backend systems with an approximately 60/40 frontend-to-backend split
Build and improve LLM-powered workflows and AI/ML infrastructure
Integrate AI agents with financial systems and customer workflows
Work directly with test customers to understand product requirements and workflow pain points
Collaborate directly with integration partners and financial technology providers
Translate customer feedback into product and engineering decisions
Own major technical projects from concept through production
Identify high-impact engineering problems independently and execute solutions with minimal direction
Make architecture and technical decisions across product, backend, financial infrastructure, and AI systems
Build reliable production systems capable of handling sensitive financial workflows
Help define the technical direction of the founding engineering organization
Operate with extreme ownership in a highly iterative startup environment