Backend Developer (Founding Team)
Gradientflo Labs · Hyderābād, India; San Francisco, CA
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- Location
- Hyderābād, India; San Francisco, CA
- Posted
Role Overview
You will own Vibecoderz’ engine room. Every interaction the TutorAgent orchestrates, every artifact generated, every certification issued — it all runs through your services. From Firestore schemas to FastAPI microservices and background workflows, you’ll design and build the backbone that powers _Superficient Learning_ for developers worldwide.
This role goes beyond writing APIs — you will define system contracts, data models, and scalability patterns that allow Vibecoderz to serve 100K+ concurrent learners with sub-100ms latency. You’ll work in lockstep with FE, AI, Prompt, and DevOps to ensure the platform’s foundation is secure, performant, and future-proof.
You’ll use Linear for sprints, Notion for PRDs, and GitHub for repos , collaborating across the team to make backend decisions visible, reproducible, and accountable.
Key Responsibilities
1. Service Architecture & APIs - Design, build, and maintain FastAPI microservices with clean modular boundaries.
2. Data Modeling & Schemas - Define Firestore schemas for users, courses, artifacts, results, and certifications. Manage Neo4j Developer Graph integration.
3. Asynchronous Workflows - Implement Cloud Tasks + Cloud Workflows for long-running jobs (certificate generation, artifact rendering, learner graph updates).
4. Commercial Layer - Integrate Stripe (subscriptions) and SendGrid (transactional email) via Firebase extensions. Ensure compliance with billing and audit standards.
5. Performance & Scale - Optimize services for high throughput with async I/O. Achieve <100ms API response time under load.
6. API Gateway & Security - Expose services through GCP API Gateway with JWT verification, rate limiting, and role-based access.
7. CI/CD Pipelines - Collaborate with DevOps to maintain GitHub Actions pipelines for automated testing, containerization, and deployment to Cloud Run.
8. Testing & Reliability - Write integration tests, contract tests, and load tests. Ensure regression-free releases.
9. Monitoring & Observability - Instrument services with OpenTelemetry for distributed tracing, logging, and metrics. Ensure failures are detectable and recoverable.
10. Cross-Team Collaboration - Work closely with PM to refine PRDs in Notion, track sprint execution in Linear, and align with AI/FE on contract stability.
11. Problem Solving - Anticipate bottlenecks (data modeling, latency, scaling) and propose architectural solutions.
Success Metrics
90 Days (Probation):
- Deploy FastAPI → Cloud Run service with API Gateway routing.
- Ship Firestore schema for Developer Graph (MVP).
- Integrate Stripe test billing and SendGrid notifications.
12 Months:
- Scale backend to handle 100K+ concurrent learners.
- Maintain 99.9% uptime with zero Sev1 backend-originated outages.
- Optimize p95 API response time <100ms under production load.
- CI/CD coverage >90% with automated regression tests.
Must-Haves
- 10+ years backend engineering experience (Python, REST/async).
- Deep expertise in distributed systems, scalable APIs, and async I/O.
- Hands-on GCP experience (Cloud Run, Firestore, Pub/Sub, API Gateway).
- Proven delivery of high-scale backend systems in product companies.
Nice-to-Haves
- Experience with Neo4j Graph DB.
- Prior work on AI product integrations (LLM orchestration, eval pipelines).
- Knowledge of Pub/Sub patterns for agentic systems.
- Startup or founding engineer background.
Tech Stack Visibility
- Core Services: FastAPI, Python Async, Google Cloud Run
- Routing & Security: Google Cloud API Gateway, Firebase Auth
- Data: Firestore, Neo4j Aura (Developer Graph), Redis
- Workflows: Cloud Tasks, Cloud Workflows
- Commercial: Stripe (Firebase Extension), SendGrid (Firebase Extension)
- CI/CD: GitHub Actions, Docker
- Observability: OpenTelemetry, Google Cloud Trace
- Tools: Linear (execution), Notion (PRDs), GitHub (repos)
Assessment
Objective: Validate ability to build scalable FastAPI backend services with async workflows and integrations.
Challenge (Candidate PoC):
Build a FastAPI backend powering an AI Tutor mock system with:
1. /generate-course endpoint → Input: “Teach me React Hooks.” Output: structured course outline (JSON).
2. /generate-artifact endpoint → Generates quiz or slide deck JSON artifact.
3. /generate-miniapp endpoint → Returns runnable JS snippet.
4. Store all results in Firestore (schemas for userId, courseId, artifactId).
5. Trigger Cloud Task for certificate generation (mock PDF).
6. Fire Firestore trigger → Send transactional email via SendGrid extension.
7. Secure endpoints with Firebase JWT verification through API Gateway.
Deliverables:
- FastAPI app deployed on Cloud Run.
- Firestore schema + example populated data.
- Postman collection for API requests.
- GitHub repo with modular code + CI pipeline.
- Short Loom walkthrough demo.
Evaluation Criteria:
- Service Architecture & Code Quality (30%)
- Data Modeling & Schema Design (20%)
- Async Workflow & Cloud Task Integration (20%)
- API Security & Performance (15%)
- Documentation & Testing (15%)
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