Staff / Principal Software Engineer

Location - San Francisco, CA (On-site) / Remote (US)

San Francisco: 6 days/week in-office (~60 hours/week, flexible). Exceptional remote candidates may work remotely 6 days/week with 1 week/month onsite in San Francisco, with travel covered.

Compensation - $250,000 – $350,000 Base + 0.5% – 2% Equity

Visa - Open to Visa Transfers (OPT, H1B Transfers)

Company Stage - Seed Stage – $10M Funding

Industry - Artificial Intelligence, FinTech, Financial Services, Autonomous AI, Agentic AI, Accounting Automation, B2B SaaS

About the Company

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.

What You'll Do

• 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

Ideal Candidate Background

Experience 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

Technical Requirements

• 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

Education

• 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

Soft Skills

• 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

Compensation & Benefits

• Base Salary: $250,000 – $350,000
• Equity: 0.5% – 2%
• Open to OPT and H1B transfers
• Opportunity to join a five-person founding engineering organization
• Significant ownership over product and technical architecture
• Direct collaboration with founders
• Opportunity to build autonomous AI systems from the ground up
• Opportunity to build financial infrastructure from scratch
• High exposure to AI, fintech, and financial automation
• Ability to directly influence product direction
• SF-based or exceptional remote opportunity
• Travel covered for approved remote candidates
• High-impact founding engineering role

Why Join

This is a rare opportunity to join an extremely early-stage AI company and help build the future of autonomous bookkeeping.

You'll work directly on AI agents capable of executing complex financial workflows while simultaneously building the accounting infrastructure, financial integrations, and product systems required to make autonomous bookkeeping work in production.

As one of the earliest engineers, you'll have enormous technical and product ownership. You'll be expected to identify problems, make decisions, ship quickly, and work directly with customers and partners.

If you enjoy building AI-native products from scratch, working across the full stack, solving complex financial infrastructure problems, and operating with extreme autonomy, this role offers exceptional ownership and impact.