# Web: Full Stack Tech Lead - Company: [Clarity]() - Location: Ideally London-based \(Hybrid\) - Remote: Yes - Team: Engineering - Employment type: Full Time - Posted: September 17, 2025 ## Job description Full-Stack Web Developer — React, FastAPI, Elasticsearch (AWS/GCP) **About Clarity** Clarity is redefining customer experience with AI. Our mission is to empower businesses to deliver faster, smarter, and more human service interactions. By combining cutting-edge AI with intuitive design, we enable customer service teams to operate more efficiently while providing customers with seamless, personalized experiences. We are **trusted by industry leaders like OpenAI, GrubHub, STC and Tabby** who rely on us to deliver real impact. Our investors include **Prosus Ventures, STV AI Fund (backed by Google) and angels from Open AI and Google**. With a 25% month-on-month growth rate and over 300% net revenue retention, this is a unique opportunity to join a hyper growth AI company and redefine an industry. As a **Full-Stack Web Developer** at Clarity, you’ll own end-to-end product surfaces—from sleek React UIs to FastAPI services and Elasticsearch search/ —shipping fast, safely, and beautifully. You’re AI-native (Cursor, v0, Claude Code in your muscle memory), comfortable in both AWS and GCP, and you treat infra & DevOps as part of building great product, not an afterthought. You’ll collaborate directly with engineers, PMs, and the CTO to turn specs into production features used by brands like **Grubhub, Booking, Dropbox & Uber**. ## **What you'll do** **50% Build — design & ship** * Build responsive **React (TypeScript)** frontends (state mgmt, data viz, virtualized tables, forms, charts, file uploads, accessibility). * Implement **FastAPI** services (async I/O, Pydantic v2, background jobs, caching) with robust testing. * Design **Elasticsearch** models & queries * Integrate AI features (streaming responses, structured outputs, eval hooks) to accelerate prototyping and user value. **25% Scale & operate** * Ship and run services on **AWS and/or GCP** (ECS/EKS/Lambda or Cloud Run/GKE), containerized with Docker. * Own **CI/CD** (GitHub Actions), **IaC** (Terraform), logging/metrics/tracing (**OpenTelemetry**, CloudWatch/Stackdriver, Grafana/Prometheus), and **SLOs**. * Optimize **p95 latency, throughput, and cost**; manage secrets, networking, VPCs, and build resilient retries/backoffs. **15% Collaborate** * Work closely with design/PM on specs and UX polish; pair with back-end/ML on data contracts and APIs. * Partner with the Insights team on taxonomy/schema changes and with Data/ML on search & analytics expectations. **10% Align & showcase** * Write crisp docs, PRDs/tech notes, and demo your work to execs & customers. * Contribute to on-call for your services and drive post-mortems to closure. What makes you a great fit * **Owner’s mindset**: you take ideas from zero → shipped → observed → iterated; you sweat details and outcomes. * **AI-native builder**: Cursor, **v0**, Claude Code (and friends) are daily drivers for rapid prototyping and refactors. * **React + TypeScript** mastery: component design, hooks, performance, testing (Vitest/Jest, Playwright). * **FastAPI** expertise: async patterns, Pydantic schemas, pagination, auth (OAuth2/OIDC), rate-limits, background jobs. * **Elasticsearch** fluency: mappings/analyzers (ngrams, synonyms), aggregations, filters, sorting, performance tuning. * **Cloud & DevOps**: solid experience on **AWS and/or GCP**, Docker, Terraform, GitHub Actions, monitoring/alerts. * **Datastores**: Postgres (SQL, migrations), Redis (caching/queues). * **Quality & security**: code reviews, type safety, lint/format, secrets mgmt, least-privilege IAM, basic SOC2 hygiene. * Communicates clearly with product sense; ships value weekly. ## **Perks and bonuses** * **Remote-first** freedom & flexible hours 🏠 * **Regular off-sites** & monthly virtual game nights 🎉 * **Unlimited vacation** (minimum 20 days encouraged) 🏝️ * **Learning budget** for conferences, courses & books 📚 * **Startup equity** in a rapidly growing market 💼 ## Apply [Apply on Clarity]() Canonical job page: