Why this role exists

6,000+ businesses use JustCall to handle every conversation that matters. Increasingly, those conversations are powered by AI — answering calls, qualifying leads, scheduling appointments, and automating workflows end-to-end.

We're hiring a Backend Developer to join the AI team and help build the integration layer that makes our AI agents actually useful in the real world. Voice agents that act — not just speak. Workflows that trigger based on what a call outcome was, not just that a call happened.

This role sits at the seam between our AI infrastructure and the business tools our customers live in. When an integration exists, you'll build workflows on top of it. When it doesn't, you'll build the integration.

What you'll actually do

• Wire up JustCall's voice agent platform (AIVA) to the business tools our customers actually use — CRMs, project management tools, communication platforms, and custom webhook endpoints.

• Design and implement trigger-based workflows: a call outcome that updates a HubSpot deal, a no-answer that enqueues a follow-up agent call, a sentiment flag that creates a Monday.com task.

• Build integrations from scratch when native connectors don't exist — REST APIs, OAuth flows, webhook handlers, event transforms.

• Work with the integrations team to extend and customize existing connectors for AI-specific use cases that off-the-shelf tools weren't designed for.

• Write Node.js services and APIs that power agent actions, workflow state, and integration payloads — with MongoDB for storage.

• Contribute to shared AI team backend infrastructure: async job queues, event pipelines, and retry/fallback patterns.

• Document what you build — integration contracts, workflow specs, API schemas — so the AI team can build on top of it reliably.

What we're looking for

• 1+ year of hands-on Node.js experience — you can design, build, and ship a backend service independently.

• Working knowledge of MongoDB: schema design, querying, and thinking through data modelling for stateful workflows.

• Comfortable with REST APIs and webhooks — you can read third-party documentation and translate it into working code without hand-holding.

• Strong debugging instincts: you can trace a broken workflow across systems, find the failure point, and fix it.

• Familiarity with the MERN stack (MongoDB, Express, React, Node.js).

• Curiosity about how AI agents work — you don't need to build the models, but you should want to understand what you're enabling.

Edges that help

• Hands-on experience with any automation or iPaaS platform — Zapier, Make, n8n, or similar.

• Experience consuming CRM or business tool APIs: HubSpot, Salesforce, Monday.com, Intercom, etc.

• Exposure to event-driven architecture or async job processing (BullMQ, RabbitMQ, SQS, or similar).

• Some familiarity with voice agent or LLM infrastructure — even if you've just read around it.

• Used Cursor or similar AI-assisted development tools in day-to-day work.

How we work

• Outcomes over output. We measure product impact by retention curves, revenue influence, and customer trust - not features shipped.

• High ownership from day one - you'll shape the product org, not inherit a finished one.

• Fast cycles, real ambiguity, and the expectation that you bring a sharp point of view and move quickly on it.

• Competitive pay tied to the product vision you set and the impact you drive.

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.