Founding Systems Software Engineer (International)

Substrate builds financial infrastructure for equipment financing, a $1.3T market that still runs on manual approvals and paper. We give equipment vendors an in-house-bank capability: AI-powered underwriting, capital-as-a-service, and point-of-sale integrations. Our customers range from construction auctioneers and CNC distributors to robotics startups. We are a team of 10+ from Ramp, SpaceX, and Anthropic, backed by a $7M seed from Floodgate, Ironspring, Neo, and Steel Atlas.

We're hiring a systems software engineer who has tackled hard technical problems help us to build core 0→1 systems at the intersection of software, hardware, and finance. You'll help architect and ship systems that power machine shops, farms, factories, construction contractors, and more.

• You believe in objective good and beauty, and you want to bring them to an antiquated, predatory industry.

• You believe not all technology is created equal. You don’t care about building another enterprise SaaS tool, you want to build tools that advance civilization.

• You want to work with people who treat their work as craft, who violently reject “just good enough,” and you want to help build that culture.

• Design and operate the backend for the loan lifecycle (application, underwriting, funding, servicing) in TypeScript on Node.js (NestJS services), PostgreSQL with Prisma migrations, and containers on AWS.

• Build asynchronous workflows with queues, retries, and recovery from partial failures related to payment collection and returns, daily loan-servicing jobs, bank-statement analysis, and credit and business-verification data ingestion.

• Model complex business workflows (credit policy, compliance checks, approvals) as explicit state machines with audit trails.

• Design and deploy production LLM and agentic systems that automate underwriting, compliance, and document processing, including evaluation and fallbacks.

• Own Postgres schema design, migrations, and query performance on production data.

• Extend our double-entry loan-servicing ledger: new transaction types and payment flows, guarded by database-level invariants and property-based tests.

• Integrate our systems with external financial partners: our bank partner for ACH origination, a bank-data aggregator, commercial credit bureaus, and business-verification providers.

• 3+ years building and operating production backend systems, with at least one substantial feature you owned from design through release.

• Production PostgreSQL experience: schema design, migrations, transactions, indexing, query performance.

• Built asynchronous systems and can explain how they handle retries, idempotency, and partial failure.

• Can walk through the hardest system you've built in depth: stack chosen, alternatives rejected, key challenges, tradeoffs.

• Clear written and verbal communication: you turn ambiguous needs into working software and explain tradeoffs to product and design.

• You've solved hard technical problems most of your peers haven't encountered and you can explain exactly how your solution works to extreme depth

• You gravitate toward thinking in systems, infrastructure, and architectural tradeoffs

• You have strong opinions about what good abstractions look like

• You resonate with our engineering philosophy

• Proficiency in TypeScript or another typed backend language

• Ledgering, double-entry accounting, loan servicing, or payments (ACH, wires, bank APIs).

• Prior regulated-fintech or lending infrastructure work

• Built and shipped agentic workflows or automations

• AWS experience, especially ECS on Fargate, Aurora PostgreSQL, S3 and CloudFront, Cognito, and Secrets Manager/KMS, managed with Terraform.

• Founder, early-hire, or new-team experience.

• Comfortable building React front ends.

• $120-$170K base + $35,000-70,000 equity

• Best-in-class medical, dental, vision

• 401K

• Unlimited vacation

If you are interested, please apply via Dover AND email [email protected], [email protected], and [email protected] with answers to the following (less than 3 sentences each):

• If you could have one person's career arc, who would it be and why?

• What's an unpopular truth you believe in?

• What's the most technically challenging system you've ever built? Include the tech stack you chose, why you chose them over other alternatives, key technical challenges and how you solved them, and any architectural tradeoffs you had to make.

• The time zone you would work from and confirm if you can overlap with at least 6 hours within 8am-5pm Pacific Time.

• Link to Linkedin, Github, personal page, or anything relevant about you online

• Resume (PDF)