Senior Full-Stack Product Engineer

KaiCalls; United States; Hybrid; USD 145,000 - 190,000; Full time

Job summary

KaiCalls seeks an experienced web application engineer to build production-grade Next.js and TypeScript features. You will own design of data models in Postgres/Supabase and integrate telephony, billing, analytics, and AI systems, with strong emphasis on end-to-end ownership and security.

The role emphasizes end-to-end ownership, incident participation, and customer research, with a focus on secure multi-tenant architecture and rapid feature delivery. Remote US-based work is supported.

Qualifications

• 5+ years building production web applications.
• Proficient in TypeScript and React.
• Strong experience with server-side APIs and SQL.
• Demonstrated debugging skills and ownership of end-to-end features.

Responsibilities

• Build Next.js and TypeScript product and API features.
• Design safe Postgres and Supabase data changes.
• Integrate telephony, billing, messaging, analytics, and AI systems.
• Write targeted tests and production-verification plans.
• Participate in incidents and customer research.

Skills

TypeScript

React

Server APIs

SQL

Debugging

Tools

Next.js

Postgres

Supabase

Twilio

Telnyx

Stripe

Job description

The mission

Increase product velocity without separating feature delivery from security, telemetry, customer proof, and production ownership.

What you will own

• Build Next.js and TypeScript product and API features.
• Design safe Postgres and Supabase data changes.
• Integrate telephony, billing, messaging, analytics, and AI systems.
• Write targeted tests and production-verification plans.
• Participate in incidents and customer research.

What success looks like

• Validated customer workflows ship predictably.
• Multi-tenant authorization remains explicit and secure.
• Regressions decrease and diagnosis gets faster.
• Mobile and desktop experiences stay action-first.

What we are looking for

• 5+ years building production web applications.
• Strong TypeScript, React, server APIs, SQL, and debugging.
• Security and multi-tenant authorization discipline.
• Evidence of end-to-end ownership.

Helpful, not mandatory

• Next.js App Router.
• Supabase and Postgres.
• Twilio, Telnyx, or Stripe.
• Applied AI product experience.

Compensation

The base salary range is $145,000-$190,000 USD for a US-remote employee. Final compensation will reflect role level, location policy, experience, benefits, variable compensation where applicable, and equity. Contractor arrangements are scoped separately.

How we evaluate

We use the same core evidence for every candidate: comparable outcomes, ownership, customer judgment, role skill, communication, and learning velocity. The process normally includes a short screen, a paid and bounded work sample, structured interviews, and reference checks.

Example paid work sample: Complete a paid, bounded repository exercise that adds a small multi-tenant workflow with a UI, API, test plan, and production-proof checklist.

Your first 90 days

1. First 30 days: Ship a low-risk production improvement and learn system boundaries.
2. By 60 days: Own one customer workflow end to end.
3. By 90 days: Deliver a meaningful outcome with tests, telemetry, and customer proof.