Backend Engineer

VoisX; Bengaluru; On-site; INR 1,200,000 - 1,800,000; Full time

Job summary

VoisX is building live voice agent platforms and seeks a backend engineer to join the Bengaluru team. You will develop FastAPI services, extend the admin console, and design scalable PostgreSQL schemas for multi-tenant workloads.

You’ll integrate telephony carriers and AI providers, ensure robust data pipelines, and contribute to production-grade deployments on Kubernetes with strong on-call responsibility.

Qualifications

• 3+ years building production backend services in Python.
• Experience with FastAPI or similar async frameworks and SQLAlchemy/Alembic.
• Knowledge of relational schema design and multi-tenant DBs.
• Docker and Kubernetes deployment experience.
• Experience integrating external APIs and handling failures.
• You reason about concurrency, timeouts, and retries by default.

Responsibilities

• Build and extend FastAPI services for organizations, projects, billing and admin console.
• Work on the LangGraph agent-execution engine — tool calling, escalation, conversation state.
• Design PostgreSQL schemas and write Alembic migrations for multi-tenant load.
• Integrate voice carriers (Twilio, Plivo) and LLMs behind stable interfaces.
• Wire up RAG retrieval over Qdrant and analytics in BigQuery/Snowflake.
• Add timeouts, retries, and observability to prevent cascading failures.
• Ship changes to a Kubernetes-deployed service with on-call production ownership.

Skills

Python

FastAPI

SQLAlchemy

Alembic

PostgreSQL

Docker

Kubernetes

Observability

Prometheus

OpenTelemetry

API Integration

Tools

Docker

Kubernetes

PostgreSQL

Alembic

Job description

VoisX's platform runs live voice agents that handle real phone calls end to end — routing, tool use, knowledge retrieval, and billing all have to hold up under real call traffic. You'll work on the FastAPI backend and the LangGraph agent-orchestration layer that powers it.

What you’ll do

• Build and extend FastAPI services that back the agent platform: organizations, projects, billing, telephony, and the admin console
• Work on the LangGraph agent-execution engine — tool calling, escalation, conversation state, and the config-driven graph builder
• Design PostgreSQL schemas and write Alembic migrations that hold up under multi-tenant load
• Integrate voice carriers (Twilio, Plivo) and LLM providers (OpenAI, Anthropic, Gemini) behind consistent internal interfaces
• Wire up RAG retrieval over Qdrant and analytical queries against BigQuery/Snowflake for customer-facing analytics
• Add timeouts, retries, and observability (Prometheus, OpenTelemetry) so failures in one dependency don't take down a call
• Ship changes to a Kubernetes-deployed service with real on-call implications — you'll own what you build in production

What we’re looking for

• 3+ years building production backend services in Python
• Solid experience with FastAPI or a comparable async web framework, plus SQLAlchemy/Alembic or similar ORM + migration tooling
• Comfortable designing relational schemas and writing migrations you'd trust against a live, multi-tenant database
• Working knowledge of Docker and Kubernetes-based deployment
• Experience integrating third-party/webhook-based APIs (payment, telephony, or similar) and handling their failure modes
• You reason about concurrency, timeouts, and retries by default, not as an afterthought

Nice to have

• Experience with LLM-based agent frameworks (LangGraph, LangChain) or building tool-calling agents
• Familiarity with vector databases (Qdrant, pgvector) and RAG pipelines
• Experience with real-time/streaming systems — WebSockets, telephony media streams, or similar
• Exposure to Terraform, Vault, or infrastructure-as-code in a cloud environment (Azure/AKS)