ByJay (CheHao) Liu
Based inBrisbane, AU / Remote
Portrait of Jay (CheHao) Liu
Jay (CheHao) Liu

6+ yrsIn practice

Software engineer.

I’m Jay. I’ve spent 6+ years building backend systems, led a 3–4 person engineering team and owned backend architecture for a B2B MVP.

I apply the same engineering discipline to LLMs, RAG and coding agents.

Production impact.Senior Backend Engineer · AmazingTalker, 2021–2023

The decisions behind the results: data platform and teacher ranking.

Applied to AI.Fig. 1 · Codex Cage demo, open source

Codex Cage. An issue becomes a pull request only after tests, a secret scan and an independent review pass.

Read the notes
SubjectArchitecture decisions and outcomes

Decisions that made a difference.

The problem, the engineering approach and the trade-off behind each outcome. Measured results are boxed.

Data warehouse & developer platform

Senior Backend Engineer · AmazingTalker · 2021–2023

Scope

Led a 3–4 person engineering team across data and service-platform projects at AmazingTalker.

Given

Business data, advertising data and in-house tracking lived in separate systems. Marketing and product teams depended on engineering work to prepare reports.

Warehouse

Built a BigQuery warehouse with Datastream CDC, Airflow and dbt, plus Metabase for self-service reporting. It unified business data with GA, Meta, Google Ads, TikTok and in-house tracking.

Platform

Built an Nx monorepo with a service generator, shared libraries and CI/CD that built and deployed only affected services to EKS. Product teams adopted it to decouple services from the main app.

30% → 5%of sprint time spent on reporting, approximately
3 daysnew data API delivery, down from about a week

RAG-based knowledge system

Freelance · 2023–2025 · Python / LLM / Vector search

Given

The client needed staff to ask natural-language questions over private documents, without sensitive content leaking between users, and without manual data prep for every new file.

Method

Built a retrieval-augmented-generation pipeline: automated ingestion, chunking and embedding into a vector store, with an LLM answering only from retrieved, permission-scoped context.

Decision

Made per-user data isolation a first-class part of the design rather than an afterthought, so security held up even as the document set and user base grew.

Properties

  • Per-user data isolation
  • Automated ingestion
  • Vector semantic search

Teacher ranking & video pipeline

AmazingTalker · 2021–2023 · Elasticsearch / Redis / AWS

Given

Full batch recomputation delayed ranking updates: new sales took about 20 minutes to appear in teacher rankings.

Method

Rebuilt ranking with Elasticsearch scoring and Redis sorted sets per locale. Event-driven updates recalculated individual teachers instead of the full batch.

Decision

Updated each teacher as their data changed, keeping rankings current without waiting for the next full recomputation.

Video

Launched teacher short videos using S3, SQS fan-out, ffmpeg on Lambda and HLS via CloudFront. Playback tracking fed teacher ranking and video recommendations.

20 → 2 minfor new sales to appear in teacher rankings
−60%ranking API latency, from 500 ms to 200 ms
1,000+video transcoding jobs per day
SubjectAgents, cloud and automation

Selected work

Applying production engineering to agents, cloud systems and developer automation.

No. 1Agentic coding

Codex Cage

An autonomous coding workflow that takes a GitHub or Linear issue through to a pull request.

Design choice

Isolate each run in a disposable sandbox; require tests and an independent review before opening a pull request.

Stack

TypeScript · Docker · Codex · CI/CD · Node.js

Read the notesSource on GitHub
Full entry

A CLI that runs an AI agent against a GitHub or Linear issue inside a disposable Docker sandbox. It implements the change, runs the project's tests, scans the diff for leaked secrets, does an independent read-only review, and opens a pull request only once every gate passes: issue to code to review to PR, fully automated. The direction is "loop engineering": a fast-to-deploy workflow you drop into any repo so AI can develop, review and raise PRs alongside your CI/CD.

Fig. 2A run from issue #72: preflight, setup, implement, verify, review, then the pull request.
No. 2Cloud AI

Strobe Assistant

A conversational assistant for your own posts and photos, combining grounded retrieval with a cloud-native media pipeline.

Design choice

Separate conversational requests from asynchronous media work, with explicit permission before mutations.

Stack

Python · TypeScript · AWS · Bedrock · S3 · S3 Vectors · DynamoDB · EventBridge · SQS · Lambda · Cognito · ECS Fargate · ALB · MCP

Read the notes
Full entry

A cloud-native conversational assistant for a user's own Strobe posts and photos. It combines Amazon Bedrock, grounded vector retrieval, a separate MCP service, asynchronous media classification and scheduled recaps, with Cognito identity and explicit permission for mutations.

Strobe Assistant ACP Chat returning dog images and a grounded story
Fig. 3Asked for dog photos, the assistant returns matching images and a story grounded in them.
No. 3Agentic knowledge

Knowledge Compiler

An agentic knowledge workspace that connects scattered notes and answers questions from your own knowledge base.

Design choice

Keep changes reviewable: attach source evidence to each proposal and leave the final apply decision with the user.

Stack

TypeScript · OpenAI Agents SDK · RAG · Express · React · PostgreSQL

Read the notesSource on GitHub
Full entry

An agentic knowledge-management tool that turns raw, messy notes into structured knowledge, generating update proposals, tracking recurring mistakes, creating review tasks and building readiness maps. A built-in RAG layer lets users ask questions in natural language and instantly surface the right note or past memory from their own knowledge base. Built on the OpenAI Agents SDK with a clean-architecture Express backend and a React + Vite client.

Fig. 4An update proposal with its source evidence, waiting for a human to apply or reject it.
No. 4Industry project

AI Meeting Management Platform

An on-premise government proof of concept built as a QUT industry project, turning recordings into draft minutes and action items.

Design choice

Keep audio and model processing on-premise; use durable asynchronous workers so long recordings do not block the API.

Stack

Node.js / Express · PostgreSQL · Python · Redis Streams · Whisper · Llama 3

Full entry

Built as a government proof of concept for the Department of Science and Technology (DOST), Philippines, through a QUT industry project, with me as the primary developer in a Brisbane-based team of six. Whisper transcribes recordings and a local Llama 3 model drafts minutes and action items for staff to review on the client's infrastructure. The Express/PostgreSQL backend handles scheduling, search, file storage and role-based access, with CI/CD and Jest tests. A transactional outbox and Redis Streams provide durable job dispatch across Node.js and Python workers; SSE reports progress without blocking the API.

Meeting Manager action items board with AI-extracted follow-ups across To-do, In Progress and Done
Fig. 5Action items extracted from meetings, tracked across To-do, In progress and Done.
SubjectRoles, most recent first

Experience

Team leadership, backend architecture and end-to-end delivery across production systems and client projects.

  1. Feb 2026 – Present

    Full Stack Engineer

    QUT Industry Project · Brisbane

    Primary developer in a six-person industry team, building an on-premise government AI proof of concept with an Express/PostgreSQL backend and durable Node.js/Python workers.

    See work No. 4

  2. Jul 2024 – Nov 2025

    Full Stack Engineer (Part-time)

    Sourect · US (remote)

    Owned the NestJS/Prisma/PostgreSQL backend of a B2B garment-manufacturing MVP, including Stripe payments and an artwork validation and vectorisation pipeline.

  3. Jul 2023 – Oct 2025

    Full Stack Engineer (Part-time)

    Freelance · Taiwan

    Delivered permission-scoped RAG, layout-preserving translation for 100+ page financial reports, and an iGaming CRM used by dozens of operations staff.

    See case W2

  4. Mar 2021 – May 2023

    Senior Backend Engineer

    AmazingTalker · Taiwan

    Led a 3–4 person team across data, ranking and service-platform work. Built engineering guidelines and an onboarding project used by ~10 engineers across teams, typically shipping to production within 3 days.

    W1 · Data & platform
    W3 · Ranking & video

  5. Aug 2019 – Mar 2021

    Backend Engineer

    WEI-PO Co., Ltd · Taiwan

    Removed Redis KEYS scans and queued settlement with RabbitMQ, cutting API time from 400 to 50 ms. Built an idempotent wallet load-tested to 2,000+ QPS and cut deployments from 30 to 5 min.

  6. Aug 2018 – Aug 2019

    Backend Engineer

    Pentium Network Technology · Taiwan

    Integrated CDN and FQDN resources across AWS, Alibaba Cloud, Tencent Cloud and GCP; built chatbot and workflow-automation systems with Kafka for real-time event processing.

  7. Apr 2017 – Jun 2018

    Backend Engineer

    Lingtelli Co., Ltd · Taiwan

    Built the company's chatbot product for Facebook and LINE and its natural-language-understanding engine, with auto-scaling and CloudWatch monitoring.

One line per role. The full bullet points are in the résumé (PDF).

SubjectBackground and skills

The engineer behind the work.

I'm a full stack and backend engineer with 6+ years building systems, from chatbot and NLU products to distributed services, data platforms and LLM-powered applications. At AmazingTalker I led a 3–4 person engineering team; at Sourect I owned backend architecture for a B2B MVP. I also spent two years freelancing part-time, designing and delivering client systems end to end.

What I care about most is the part users actually feel: speed, reliability, and whether things still hold up as they grow. I like taking something slow, fragile or messy and turning it into something fast, observable and easy for the next engineer to pick up, and I try to back decisions with real numbers rather than opinions.

Right now I'm completing a Master of IT at QUT in Brisbane, and most of my own time goes into agentic AI, building things like an autonomous issue-to-PR coding agent and a tool that compiles raw notes into structured knowledge. I'm looking for backend or AI engineering roles where I can keep working where solid systems meet applied AI.

On the practical side: I'm based in Brisbane on a student visa with work rights now, and on finishing my Master I move to a Temporary Graduate visa (subclass 485) with full, unrestricted work rights, so no employer sponsorship is needed in the near term, with a longer-term view to permanent residence.

Languages & web

  • Go
  • Python
  • TypeScript / Node.js
  • Ruby
  • C#
  • NestJS / Express
  • FastAPI
  • React / Tailwind CSS
  • REST / GraphQL

Data & events

  • PostgreSQL / MySQL
  • Redis / Elasticsearch
  • BigQuery
  • dbt / Apache Airflow
  • CDC
  • RabbitMQ / Kafka
  • Event-driven architecture

Cloud & DevOps

  • AWS / GCP
  • Docker
  • Kubernetes (EKS)
  • GitHub Actions CI/CD
  • New Relic
  • Nx

AI & tools

  • RAG / Vector databases
  • Llama 3 / Whisper
  • Amazon Bedrock
  • Agentic workflows
  • MCP / ACP
  • Claude Code
Education
QualificationInstitutionDates
Master of Information TechnologyQueensland University of Technology, BrisbaneFeb 2025 – Nov 2026 (expected)
Bachelor of Computer ScienceNational Taiwan University of Science and Technology, TaiwanJun 2011 – Jan 2015

Let’s build dependable systems.[email protected]

Open to senior backend and applied AI roles. Based in Brisbane, available for local and remote opportunities.

Student visa with work rights now. Full work rights on a Temporary Graduate visa (subclass 485) after my Master in Nov 2026, so no sponsorship is needed.

© 2026 Jay (CheHao) Liu · Brisbane, AustraliaBack to sheet 1