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Fiverr Pro
English
$
USD
Nduka Marvelous
@alonso_williams
Level 1
AI Voice Agent Developer, Call Automation Scheduling with Retell n8n GoHighLevel
Nigeria
English, Spanish
About me
Welcome! I am a specialized AI Voice Agent Developer and a recognized "Fiverr's Choice" provider with 2+ years of production experience.
My expertise lies in automating appointment booking and deep CRM automation using Retell AI, GoHighLevel, and n8n. I do not build generic bots; I architect custom AI voice agent systems that completely eliminate your manual workloads.
I provide an elite, consultative experience from our first message to final deployment.
Reach out today, and let's map out the perfect AI architecture for your business.
Skills
Nduka Marvelous
$15/hour
Offline •
Average response time: 1 hour
See my services
Automations & Agents
I will build ai voice agent vapi ai appointment gohighlevel n8n retell ai cold caller
Automations & Agents
I will set up claude cowork teach claude cowork consultant claude ai agent integration
Want to work on an hourly basis?
Tell Nduka Marvelous what you need.
$15
/
hourPortfolio
Work experience
Outbound Voice AI Agent Developer
Premier Real Estate Agency • Freelance
Feb 2026 - Present • 3 mos
Eliminated human sales team burnout from manual dialing by developing a relentless outbound Voice AI Agent. Orchestrated Retell AI and n8n to instantly dial new web leads within 60 seconds of form submission. The AI Agent Development included advanced objection handling, seamless pipeline stage updates in GoHighLevel CRM Automation, and an automated SMS fallback system via n8n
Luxury Travel Chatbot & Voice AI Agent Engineer
Luxury Travel Agency • Freelance
Feb 2026 - Present • 3 mos
Addressed the pain point of managing complex, multilingual booking inquiries. Engineered an omnichannel Chatbot and Voice AI Agent using the OpenAI API and JavaScript. The system utilized complex routing to handle flight availability checks, providing sub-second latency responses and seamless handoffs to human agents.
Vapi Voice Agent Developer & Prompt Engineer
Vox AI Solutions • Freelance
Jan 2026 - Present • 4 mos
As a Vapi Voice Agent Developer, I specialize in prompt engineering, conversational AI, human-like voice agents, Vapi configuration, system prompts, latency optimization, objection handling, bilingual agents, voice cloning, speech-to-text optimization, text-to-speech tuning, ElevenLabs integration, deepgram configuration, function calling, structured outputs. Hire voice AI developer to create human-sounding receptionists, Vapi expert to optimize system prompts for natural pacing, prompt engineer for objection handling scripts, AI voice developer for multilingual support, expert to fix Vapi latency issues. Using tools like Vapi, OpenAI GPT-4o, Claude, ElevenLabs, Deepgram, Retell AI, JSON schemas. Job tags: AI Agent Development, Artificial Intelligence, Chatbot Development, Prompt Engineering, Natural Language Processing, English, Voice-Over. This role focuses on eliminating robotic tones, refining conversation flow, and maximizing user engagement.
19 Reviews
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Rating Breakdown
- Seller communication level
- Quality of delivery
- Value of delivery
1-5 out of 19 Reviews
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Most relevant
shonna1
United States
I was interested in having a Bot set up to make 200-250 cold calls f real estate a day. After doing my research I found out that can not happen. The limit is 100 calls per day. Also their are other things that have to be set up before you can do this. -Seller did not advise me of this. I explained...
Helpful?
ali_otn
Repeat Client
Morocco
Working with Marvelous was a great experience. He successfully built and automated our AI voice calling system using Retell AI, GoHighLevel, and n8n. The project included AI outbound calling automation, CRM integration, appointment booking workflows, callback handling, and automatic call summaries synced...
Helpful?
ali_otn
Repeat Client
Morocco
Marvelous delivered exactly what was promised! He successfully built an inbound AI voice agent using Retell AI and the ElevenLabs voice integration sounds incredibly natural to callers. The n8n automation works flawlessly behind the scenes, seamlessly booking appointments and pushing accurate customer...
Helpful?
felix_jake
United Kingdom
Working with this Marvelous was an excellent experience from start to finish. Communication was clear, professional, and fast. He understood exactly what my real estate business needed and built an AI voice agent that works perfectly. It sounds natural, captures leads accurately, and even books appointments...
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neuel_javier
Australia
Great experience working with Marvelous! He quickly understood the issues with my AI agent and fixed both the response quality and the Google Calendar integration. Communication was smooth, and he delivered exactly what was promised. Everything is now working perfectly. Highly recommend if you need help fixing or improving an AI agent. Thanks again!
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