Technical Co-Founder / CTO
Company Description
BLACKLINE is an exclusive private membership platform designed to provide an exceptional experience in aesthetics, wellness, fitness, and personal care across London. We pride ourselves on a meticulously curated network of top-tier operators to meet members' high standards. With a focus on personalized attention, BLACKLINE offers a seamless and bespoke experience. Membership is granted selectively, catering to individuals who value excellence and exclusivity.
🧠Technical Co-Founder / CTO — BLACKLINE
Overview
BLACKLINE is a private, invite-only membership across London focused on health, beauty, and personal care.
We are building a concierge layer powered by AI — designed to handle booking, coordination, and member preferences across messaging and voice, with the standard and discretion expected of a private members’ network.
This is not a typical startup role.
We are building infrastructure for experience, not a product for scale.
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What You’ll Build
You will architect and ship the BLACKLINE Concierge Agent, operating across:
1. WhatsApp (Primary Interface)
* Natural conversation handling (LLM-driven)
* Booking coordination with providers
* Memory of member preferences
* Context-aware responses (time, location, history)
2. Voice (Phone Concierge)
* Real-time conversational agent
* Natural, human-like voice (e.g. ElevenLabs or equivalent)
* Call handling (inbound + outbound)
* Seamless escalation to human when required
3. Backend Intelligence Layer
* User profiles + preference memory
* Provider availability + scheduling logic
* Workflow orchestration (requests → bookings → confirmations)
* CRM integration
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Core Responsibilities
* Design and build the end-to-end AI concierge system
* Select and integrate LLMs, voice models, and orchestration frameworks
* Build WhatsApp automation (e.g. via Twilio, Meta APIs, or equivalent)
* Implement real-time voice pipeline (speech-to-text → reasoning → text-to-speech)
* Ensure low latency and high reliability
* Maintain strict data privacy and security standards
* Define architecture that scales without degrading experience
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Technical Requirements
You should have strong hands-on experience in:
AI / LLM Systems
* Prompt engineering + agent design
* Tool use / function calling
* Memory systems (vector DBs, session memory)
* Multi-step workflow orchestration
Voice Systems
* Real-time speech pipelines (STT / TTS)
* Latency optimisation for conversational flow
* Experience with providers like ElevenLabs or similar
Messaging Infrastructure
* WhatsApp API integrations
* Event-driven systems
* Webhooks and async processing
Backend Engineering
* Node.js / Python (preferred)
* API design
* Database design (relational + vector)
* Cloud infrastructure (AWS / GCP)
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What We Care About (More Than Stack)
* You ship fast — not just design systems
* You understand user experience in conversation, not just code
* You can balance automation vs human touch
* You care about detail, tone, and discretion
This is not:
* a chatbot
* a support tool
* a generic AI assistant
It must feel like:
👉 a private concierge that already knows the member
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Nice to Have
* Experience building AI agents in production
* Experience with booking / scheduling systems
* Familiarity with CRM tools (HubSpot, custom pipelines)
* Background in high-end consumer or service experiences
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Stage & Commitment
* Early-stage / pre-scale
* Building MVP → live concierge → refined system
* Equity-based co-founder role
* London-based preferred (not mandatory)
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What Success Looks Like
* A member can message or call BLACKLINE
* Make a request in natural language
* Have it handled seamlessly end-to-end
No friction.
No repetition.
No drop in standard.
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Why This Matters
Most AI products optimise for efficiency.
We’re optimising for:
* trust
* consistency
* experience
If you get this right, you’re not building a feature —
- you’re building the operating system of the brand.