AI Growth Engineer-AI Marketing Systems in London

LEC AI is building an AI-powered marketing operating system for LEC group's four brands (AI, robotics, beverages, UK-China trade), and productising it. You'll own it end-to-end: persona layers, digital humans, signal-triggered outbound, data indices, and the agent army. This is a builder role in live production, not an R&D lab.

What you'll build

• Brand-brain content engine: RAG + knowledge-graph (pgvector, Neo4j) on a 4-layer memory stack, drafting on-brand content from real meeting transcripts across 4 brands, with per-brand compliance gates.
• AI persona layer: per-employee personas grounded in voice-ID'd meeting data: in-voice drafting to avatar video to conversational agents; Mandarin dubbing/localisation (one video, five languages).
• Self-hosted digital-human pipeline: MuseTalk/LivePortrait/HeyGem-class OSS on RTX 4090-class GPUs; cloned TTS; RTMP streaming; sub-3s latency; AI livestream host for lead-gen and commerce.
• Compliant variation engine: one story, platform-native cuts per persona/brand, all disclosed and watermarked.
• Meeting→publish pipeline: WhisperX to diarization to clip to caption to multi-platform scheduling, fully automated.
• Signal-Triggered Growth Engine: Companies House, premises-licence, and venue-signal watchers firing persona-led outreach across our 16,681-venue LeadGen DB (Clay + n8n).
• Proprietary Data Index Engine: quarterly indices from our operational data (on-trade, robotics deployment, UK-China trade), built for journalist and AI-engine citation.
• AI Fame Engine: newsjacking, journalist pitching, and SoS/Featured/Qwoted response automation on Donnie's insight memory.
• WhatsApp Trade-Ordering Agent: venue reorders via WhatsApp Business Platform (Twilio/360dialog).
• AI phone agents: Vapi-class voice agents with UK data residency, consent-gated.
• Creative-Testing Factory: brand-brain generates 50-100 ad variants, auto-launches on Meta Advantage+/TikTok Smart+, auto-kills losers, winners feed back.
• Synthetic focus-group layer: pre-publish testing on AI personas built from first-party audience data.
• Agent-ready commerce: MCP/ACP endpoints, structured feeds, llms.txt/ai-catalog, schema for agentic discovery and buying.
• The agent army: ~40 agents spanning content, distribution, fame, revenue, analytics, commerce, and ops (LangGraph/CrewAI, self-hosted n8n as glue), including a Launch-Orchestrator ("product goes out, everything fires"), attribution tracking, consent/rights tracking, and brand-compliance checks (ASA/CAP/Portman, EU AI Act labelling).

Must-have

• 3+ years shipping production AI/LLM systems: RAG, embeddings, vector DBs, agent frameworks (LangGraph, CrewAI, or equivalent).
• Hands-on with the 2026 gen stack: video-gen APIs (Veo/Kling/Seedance-class), voice cloning, avatar/lip-sync models.
• Self-hosting: Docker Compose, GPU inference, OSS model deployment (comfortable running Chinese OSS models locally).
• Automation at scale: n8n, API integration across Meta, TikTok, LinkedIn, WhatsApp Business Platform, HubSpot, Companies House.
• Startup builder: shipped scrappy systems solo or in a tiny team.
• Growth engineering: outbound infra, enrichment (Clay), deliverability, creative-testing loops.
• GEO/AI-search: how ChatGPT/Perplexity/AI Overviews cite and rank sources.
• UK compliance surface: GDPR biometric consent, PECR Reg 19, ASA/CAP; you build the gates.
• Mandarin or China-tech ecosystem familiarity (Douyin/WeChat/Xiaohongshu, ByteDance tooling).
• Newsletter/community infra (beehiiv APIs), data-pipeline/BI experience for the Index Engine.

How we work

• Join LEC AI's 6-engineer team, the team that built Donnie, our self-hosted AI Chief of Staff (4-layer memory, audio pipeline, MCP-connected).
• Ship weekly; every build has a kill/scale threshold.
• Built to be productised for 10-100 person companies; you're building product, not rewriting internal tooling.