Backend Developer SR (AM - BE - 20260512)

Celaralabs; Buenos Aires; Presencial; ARS 104.272.179 - 134.064.231; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Talented senior team

Greenfield rebuild

Path to lead the team

Descripción de la vacante

Celaralabs in Buenos Aires is seeking a skilled AI-empowered engineer to build and launch a new digital purchase platform. You will work with a modern stack to run the full purchase flow online, integrating multiple third-party provider APIs, and developing AI-enabled product features.

This role requires strong Python back-end experience and a commitment to engineering quality. You will lead a senior team on an exciting greenfield project with opportunities for growth into a leadership position.

Formación

• 6+ years building production back-ends; comfortable owning a service end-to-end.
• Experience with FastAPI or similar modern frameworks.
• Hands-on with agentic AI tooling in the SDLC.

Responsabilidades

• Build and own provider connectors on the new integration framework.
• Lead by example on technical direction.
• Ship AI features end-to-end against the lighthouse roadmap.

Conocimientos

Python back-end experience

API integrations at scale

Agentic AI tooling

AWS or GCP

Terraform

Herramientas

FastAPI

Docker

CI/CD pipelines

Descripción del empleo

We're looking for a modern, AI-empowered engineer — strong fundamentals, opinionated about good design, and experienced in both agentic development tooling and AI-enabled product features — to help build and launch a new digital purchase platform. Someone who codes fast, leads by example, and can hold their own in product conversations as easily as in technical ones.

The project is for a major company modernizing how customers buy online — standing up a modern stack to run the full purchase flow online, end-to-end. We're building a brand-new back-end: a modern integration layer to multiple third-party provider APIs, the AI plumbing to power agentic features across the funnel, and an agent‑facing dashboard ("Agent Co‑Pilot") that lets human agents see live shoppers in real time and jump into the conversation when needed. The first AI lighthouse is a customer-facing chat assistant tied into that same plumbing — pricing, configuration, eligibility checks, hand‑off to a human. This is a 3‑month foundation build with a senior, hand‑picked team, kicking off ASAP.

Responsibilities

• Build and own provider connectors on the new integration framework — auth, retries, webhooks, observability, etc.
• Lead by example on technical direction — drive design discussions, unblock the team, and own the hardest pieces of the stack.
• Partner with the client's PM and product stakeholders in 1–2 week sprints — daily standups, weekly demos — pushing back on scope, proposing better solutions, and translating product intent into clean technical bets.
• Ship AI features end‑to‑end against the lighthouse roadmap (chatbot, Agent Co‑Pilot, plumbing for what comes next).
• Set engineering practices the permanent team will inherit — clean code, tests, AI‑generated docs, CI/CD, eval harnesses on LLM‑touching code paths.
• Pair with the architect and tech lead on cross‑cutting design; mentor through code review.

Benefits & Opportunities

• You'll be working alongside a talented, hand‑picked senior team.
• Greenfield rebuild, not legacy maintenance. We're migrating off the current vendor's platform onto a new, clean, modern codebase. You'll set the future patterns the new system gets built on.
• Best‑in‑class agentic‑AI SDLC from day one. You'll help design the patterns — Claude Code across the full SDLC, AI‑generated documentation, evals on every LLM‑touching feature, observability built in.
• Interesting consumer AI features — a live‑shopper dashboard, an in‑funnel AI chatbot, and the plumbing for everything that comes after.
• Path to lead the team going forward. This 3‑month build is Phase 1. The client will then ramp a permanent squad on top of the codebase you helped create — clear path into the lead role.

Qualifications

• 6+ yrs building production back‑ends; comfortable owning a service end‑to‑end
• Strong Python back‑end experience, ideally with FastAPI or similar modern frameworks; TypeScript/Node experience is a plus
• Built and maintained third‑party API integrations at scale — auth, retries, rate limits, webhooks, idempotency, observability
• Hands‑on with agentic AI tooling in the SDLC — using tools such as Claude Code to accelerate development, improve documentation, support testing, and raise engineering quality
• Experience building AI‑enabled product features — LLM APIs, tool/function calling, prompt design, structured outputs, eval harnesses, monitoring, and regression checks for LLM‑touching workflows
• Opinionated and direct — pushes back on scope, holds the bar on docs, tests, maintainability, and product‑quality engineering
• Cloud + IaC — AWS or GCP, Terraform, Docker, CI/CD pipelines
• Bonus: familiarity with .NET‑based platforms or enterprise systems, especially when extending or integrating with an existing .NET application
• Bonus: VLM/RPA or browser‑automation experience for provider fallback paths