Backend Engineer AI

7 days ago

Bucharest Metropolitan Area, Romania Salestools Full time 40,000 - 80,000 per year

Why We Exist

Enterprise and mid-market sellers juggle fractured processes, mountains of data, and relentless pressure to persuade. With 700,000+ B2B reps in the U.S. alone, individual sellers are drowning in manual work. is changing that — 100×.

Our first AI employee, Olivia (SDR), already drives $10M in new ARR every month for customers by automating prospecting, research, outreach, and meeting booking. Backed by top investors, we're scaling the platform into a full-stack roster of human-like digital workers.

(On a sidenote: yes, we're VC-backed and growing fast.)

Your Mission

Join our founding engineering team to design the high-performance back-end and data systems that power these Agentic AI Sales Workers. Your code will shape the product, culture, and millions of future workflows.

What You'll Own

  • Architect & build core micro-services in Python that orchestrate LangGraph/LangChain agents, ElasticSearch vector search, and NoSQL stores.
  • Embed AI natively into sales workflows — APIs that plug directly into Olivia and future agents.
  • Containerize & ship: craft Docker images, helm charts, and GitHub Actions pipelines for zero-touch releases.
  • Scale globally on AWS/GCP: design fault-tolerant, multi-region deployments and blazing-fast data layers.
  • Level-up the craft: champion best practices, performance tuning, and observability across the org.

Must-have qualifications

  • 3–5 years of professional experience in back-end or distributed systems engineering
  • Python proficiency with modern async patterns and strong design instincts
  • Experience with PostgreSQL, MongoDB, Redis Hands-on with Docker, Kubernetes, and CI/CD automationProficiency with Git/GitHub or Bitbucket
  • Experience with queue workers, background tasks, and WebSocketsStrong grasp of cloud infrastructure (AWS, GCP, Azure) and distributed architectures
  • Clear written & spoken communication; can explain complex ideas to non-technical stakeholders
  • Ownership mentality: outcome-driven, resilient under deadlines, thrives in structured and chaotic environments

Preferred qualifications

  • Experience with ElasticSearch (vector search, scaling queries)Familiarity with LangGraph / LangChain and AI/ML integrationsLarge-scale web scraping systems (Playwright, crawlers, etc.)
  • PHP/Laravel services in production
  • React / NextJS familiarity to collaborate with front-end teams
  • Strong problem-solving mindset: proactive, detail-oriented, creative, curious
  • Past experience in startups or as a founder/early team member

The Stack

  • Python | LangGraph | LangChain | PostgreSQL | ElasticSearch | MongoDB/DynamoDB | Redis | PHP/Laravel | React/NextJS | Docker & Kubernetes | AWS & GCP | Playwright | GitHub Actions | CI/CD | WebSockets | Queue workers | Low-level optimization (memory, concurrency)

How We Work

  • Velocity with quality: small PRs, rapid feedback, automated tests, prod telemetry.
  • Ownership mentality: engineers talk to customers, shape roadmaps, and push fixes in hours — not sprints.
  • Research × Product: tight collaboration with Salestools AI Labs to productionize cutting-edge agent research.

Growth Path (12 months)

  • Drop agentic response latency below 100 ms at 10× current load
  • Lead two 0→1 projects that double user activation or revenue
  • Mentor new hires as the team scales from single-digits to 25+ engineers

Perks & Benefits

  • Competitive salary matching your skills
  • Meaningful equity over time
  • Annual bonus
  • Choose-your-gear setup
  • In-office-first culture
  • Direct access to founders & investors

Ready to build the future of work? Apply now.

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