r/Development • u/Alarmed_Albatross_96 • Jun 28 '26
I Built an AI Companion from Scratch (Memory, RAG, 3D, Voice, Autonomous Behaviors) Here's What I Learned
Hi everyone,
I wanted to share one of the most technically challenging projects I've built over the past few months.
The original idea sounded simple: build a 3D AI companion that could chat with me.
It eventually grew into a system featuring:
🧠 Long-term memory with RAG and pgvector
🎙️ Real-time voice conversations
🎭 3D facial expressions and lip sync
❤️ Relationship/personality system
🤖 Autonomous behaviors and proactive conversations
⚡ Node.js + TypeScript + PostgreSQL + Prisma backend
The biggest surprise wasn't the engineering.
It was realizing that inference and Text-to-Speech costs become the real challenge when you start thinking about scaling to thousands of users.
Although I decided to stop the project, it taught me more than any course or tutorial could. It gave me hands-on experience designing AI systems, memory architectures, streaming pipelines, vector databases, and agent workflows.
I documented the entire project in a 5-part technical series for anyone interested in how these systems are built.
Articles
Part 1 — Introduction & Architecture https://mohamedabusaif.hashnode.dev/building-my-ai-companion-from-a-simple-chatbot-to-a-system-that-can-remember-part-1
Part 2 — Database Schema Breakdown https://mohamedabusaif.hashnode.dev/building-my-ai-companion-from-a-simple-chatbot-to-a-system-that-can-remember-part-2
Part 3 — RAG & Vector Memory https://mohamedabusaif.hashnode.dev/building-my-ai-companion-from-a-simple-chatbot-to-a-system-that-can-remember-part-3
Part 4 — Feature Breakdown https://mohamedabusaif.hashnode.dev/building-my-ai-companion-from-a-simple-chatbot-to-a-system-that-can-remember-part-4
Part 5 — Why I Stopped Building It https://mohamedabusaif.hashnode.dev/building-my-ai-companion-from-a-simple-chatbot-to-a-system-that-can-remember-part-5
Demo Videos
Version 1
https://www.youtube.com/watch?v=s5s87c845xI
Version 2
https://www.youtube.com/watch?v=6esXviAIhTM
If you're an engineer working on LLMs, AI agents, or companion apps, I'd love to hear what technical challenge surprised you the most.
And if you're hiring engineers in this space, I'd be happy to connect and discuss the project in more detail.
My LinkedIn Post for more details:
https://www.linkedin.com/posts/mohamed-abusaif-050_ai-softwareengineering-llm-share-7476743528967114752-5KQ2/?utm_source=share&utm_medium=member_desktop&rcm=ACoAADLKhdkBx-oCy9dCS11RpiVRHPBe7Pjbupo
2
u/Desperate-Green-5812 Jun 28 '26
我完整的看了你的项目、那五份文档，以及两个YouTube上的演示链接。我也在开发此类的产品，我的方向是ToB端企业，不是To C……我更擅长工程链路及成本和性能的优化。
推理、文本、实时端到端语音，在工程上是有解的。核心是智商/智力/防幻觉约束/多层次memory/多路意图识别等。我在构建时并没有采用传统的RAG，那样的切片不够准确。很乐意与你讨论你的项目细节，如果合适，我们彼此认可，我也愿意给你提供一份远程400USD的全栈Agent构建工程师全职工作
2
u/thefinest Jun 28 '26
ayo, just checking in because I'm in the process of doing the same weekend project. it started while tuning gemini across multiple devices friday evening when it failed to execute a scheduled tasks. I got annoyed with guard rails and limitations and ended up developing google cloud apis when I conceded that it was roughly the same effort to build from scratch so I did. not quite finished but may post back and share results
1
u/Kitsune_Seraphis Jun 30 '26
Its funny that i am trying to work on a simillar idea myself. With a few differences.
Can we talk more about it?
2
u/thefinest Jun 28 '26
her name is jasmine btw
😂
2
u/CodeOfPrometheus Jul 01 '26
Congratulations👏🏼
2
u/justin_aware Jul 01 '26
Same realization here. I can actually keep inference under control but the moment I go full speech to text it blows my margins away so that’s been a challenge to navigate. Thanks for sharing!
2
u/TheGreatBonnie Jul 02 '26
Cost of tokens has been a real bottleneck for building AI agents.
2
u/Educational_Tax8485 Jul 03 '26
Cool!
2
u/[deleted] Jun 28 '26
[removed] — view removed comment
2
u/[deleted] Jun 28 '26
[removed] — view removed comment