Software Development Engineer II

Why this role exists

JustCall is building AI voice agents that do more than just have conversations. They answer calls, qualify leads, schedule appointments, update CRMs and trigger business workflows autonomously.

But for these AI agents to be truly useful, they need to work seamlessly with the tools businesses already rely on. A conversation should be able to trigger an action, update a deal, create a task or initiate the next step in a workflow without human intervention.

That's where you come in.

We're looking for a Backend Engineer who enjoys building integrations, connecting systems and making AI powered workflows work reliably in the real world. You'll work at the intersection of our AI infrastructure and the business applications our customers use every day, helping bring JustCall's AI capabilities into their existing workflows.

You'll build integrations where they don't exist, extend existing connectors for AI specific use cases, and develop the backend services that allow our voice agents to take meaningful actions.

What You'll Actually Do

• Build AI powered integrations: Connect JustCall's AI voice agent platform (AIVA) with the business tools our customers use, including CRM's, project management platforms, communication tools and custom webhook endpoints.

• Develop integrations from scratch: Build integrations when native connectors aren't available, working with REST APIs, OAuth flows, webhook handlers and event transformations.

• Extend existing connectors: Collaborate with the integrations team to customise existing connectors and support AI specific workflows that traditional integrations weren't designed for.

• Build backend services: Develop Node.js services and APIs that power agent actions, workflow execution, integration payloads and state management, using MongoDB for data storage.

• Contribute to AI infrastructure: Work on shared backend systems supporting asynchronous job processing, event pipelines, retries and fallback mechanisms to ensure workflows execute reliably.

• Design reliable API contracts: Document integration specifications, workflow behaviour, API schemas and integration contracts so other engineering teams can build on top of them.

• Own features end to end: Take ownership of development, testing, debugging and deployment while collaborating with the AI and integrations teams to deliver reliable solutions.

What We're Looking For

• Strong backend fundamentals: 3+ years of hands on experience with Node.js and JavaScript or TypeScript, with the ability to independently design, build and ship backend services.

• Database fundamentals: Working knowledge of MongoDB, including schema design, querying, data modelling and managing state across workflows.

• API and integration experience: Comfortable working with REST APIs, webhooks and third party integrations. You should be able to read API documentation, understand authentication flows and translate requirements into working integrations independently.

• Problem solving and debugging: Strong debugging instincts and the ability to trace issues across multiple systems, identify failure points and build reliable solutions.

• Full stack familiarity: Familiarity with the MERN stack (MongoDB, Express, React and Node.js), with a strong preference for backend engineering expertise.

• Product and engineering mindset: Ability to understand how a feature or integration fits into the larger product experience and translate requirements into practical engineering solutions.

• Curiosity about AI: Genuine interest in understanding how AI agents and LLM powered applications work, particularly how they interact with external systems and execute business workflows.

The bigger picture

JustCall is SaaS Labs' flagship product used by 6,000+ businesses across 70+ countries to run their customer conversations. We're backed by Peak XV and Base10 Partners, have crossed $40M ARR, and are building toward $100M with the team, the product, and the infrastructure to get there.

If this is the role you've been waiting to find - let's talk.

SaaS Labs takes pride in being an equal opportunity employer. We believe diverse teams build better products, which is why we're committed to making hiring or any employment decision regardless of race, colour, religion, national origin, age, sex, marital status, ancestry, disability, genetic information, veteran status, gender identity, sexual orientation, or any other characteristic.