Senior Full-Stack engineer (Typescript)

Senior Engineer

UserEvidence is a SaaS platform that unlocks stories from happy customers, and automatically creates a library of beautiful content assets. We are the only platform purpose-built to unlock customer love at scale. Credibility and noise are huge issues in B2B marketing and sales. We believe companies can sell a lot more when they let their customers do the talking, and show real-life evidence and feedback from their users.

About this role. UE Advocacy is a customer advocacy product we acquired because it fits our north-star mission. The product demos beautifully and customers love what it does, but the codebase was built fast and is now showing the strain. We are in active remediation: porting a legacy Express API to a modern Hono/Bun backend, decomposing oversized React pages, hardening data integrity, retiring AWS Lambdas in favor of in-monorepo BullMQ workers, and adding real test and observability coverage. We need senior engineers who can ship inside a codebase under construction, follow established patterns rigorously, and trust the safety net (canary deploys, feature flags, automated review) instead of relying on manual full-app QA.

Stack

• Language: TypeScript (strict mode on new code)
• Backend: Hono on Bun, OpenAPI-driven routing, Prisma + PostgreSQL, BullMQ for background jobs and crons, AsyncLocalStorage-aware transactions
• Frontend: Next.js (Pages Router), React Query, Tailwind, Base UI primitives, an auto-generated SDK client from OpenAPI
• Testing: Bun test runner with factory-based real-DB integration tests; Vitest + React Testing Library for components; Playwright for E2E
• Infra & observability: Render, AWS, New Relic, PostHog feature flags, Auth0
• Tooling: Macroscope automated code review, a comprehensive in-repo agent guide, and canonical reference modules that define the patterns we expect every new module to match

Responsibilities

You'll be part of a senior engineering team responsible for stabilizing and evolving UE Advocacy. Depending on focus area, you may work in one of three lanes:

• Re-architecture. Port modules from the legacy Express API to the new Hono API with full integration test coverage. Decompose large React components (3,000-5,000 LOC pages) and convert.jsx to strict-mode .tsx. Improve frontend performance — bundle splitting, dynamic imports, mobile-first defensive coding, embed reliability. Harden data integrity by introducing real state machines and typed enums.
• Feature work. Build new customer-facing features behind feature flags with canary rollouts, against PM-written acceptance criteria. Follow established backend patterns and frontend conventions exactly — we have reference modules for a reason.
• Bug triage and fixes. Investigate customer-reported bugs using New Relic traces, structured logs, and database queries. Reproduce, fix, and add tests to prevent regression. Most bugs live in legacy code; finding them is a code-archaeology skill.

Across all three lanes, you will:

• Write clean, maintainable, well-tested code following established patterns
• Conduct thoughtful peer code reviews and respond constructively to the same
• Use automated code review (Macroscope), automated tests (Bun, Vitest, Playwright), and canary deploys as your safety net — not manual full-app QA
• Troubleshoot production issues using New Relic, structured logs, and direct database queries