ByteX

Tokyo · Product Studio

Build it. Ship it.Grow it.

ByteX is a Tokyo software studio that builds and operates its own products, and brings that hands-on experience to client projects. We specialise in multilingual products, AWS serverless architecture and putting LLMs to real work.

See our productsDiscuss a project
  • Products in production
  • 日本語 / English / 中文
  • AWS serverless
  • LLM in production

Products

Products we run

Services we plan, design, build, host and operate ourselves, end to end.

LiveOur product

NAGI Freediving

A trilingual freediving-school site where the AI completes the booking

Official site of a freediving school operating in Okinawa and Izu. Courses, dive sites, a learning library and a journal in Japanese, English and Chinese, with language routing decided at the CloudFront edge by visitor region. An AI concierge running on Claude via Amazon Bedrock answers questions, confirms name, dates and party size, and completes the booking.

  • Astro
  • AWS S3 / CloudFront
  • Amazon Bedrock
  • Claude
  • JA / EN / ZH
Visit sitenagifreediving.com
nagifreediving.com
NAGI Freediving screenshot
LiveOur product

Settle

A job board for foreigners in Japan that states visa and Japanese-level facts up front

Japanese job ads rarely say whether the employer sponsors a visa, how much Japanese you really need, or whether foreign staff are welcome. Settle has an LLM read every listing and label those three things with quoted evidence. Listings stay in the original Japanese; the UI and labels are in English, Chinese and Vietnamese. Around 2,500 Tokyo listings are ingested continuously and served as a fast static site.

  • Astro
  • Python
  • Claude
  • AWS
  • EN / ZH / VI
Visit sitesettlejobs.com
settlejobs.com
Settle screenshot
See all products

Lab

In the lab

We build the things we want to use first. These projects are being validated with real users.

  • In development

    TangPingList

    Start from a budget, find the cities you can live in. A relocation community for Chinese speakers

    • Next.js
    • Supabase
    • PostgreSQL
  • In development

    Diving Hub

    Matching dive travellers in Japan with certified instructors

    • React
    • FastAPI
    • PostGIS
    • Stripe
  • In development

    SwapIt

    A location-based app for swapping things with neighbours

    • Next.js
    • PostGIS
    • Socket.IO
    • Flutter
  • R&D

    Host Pilot

    One console for short-term-rental hosts: multi-OTA bookings plus AI-drafted messages

    • FastAPI
    • Next.js
    • LLM
    • Stripe
  • R&D

    ByteX Search

    An in-house search engine combining BM25 with vector retrieval

    • OpenSearch
    • BM25 + Vector
    • Scrapy

Why ByteX

We support your development from the perspective of people who ship products.

Unlike a pure outsourcing shop, we operate our own services every day. That experience goes straight into your project.

  1. 01

    Designed for operations

    A release is not the finish line. We design for running cost, monitoring and the improvement loop, and can propose the exact setups we run in production.

  2. 02

    Multilingual by default

    We have designed and operated products in Japanese, English and Chinese. Services for foreign residents, inbound visitors or overseas markets get the right foundations from day one.

  3. 03

    AI that actually works

    We do not stop at demos. Assistants that complete a booking, data labelling with quoted evidence: we implement LLMs where they create value inside a workflow.

  4. 04

    Small, fast, evidence-driven

    A small team means fast decisions. We propose shipping a minimal scope early and growing it with data.

Services

How we help clients

The technology and the way of working from our own products, applied to yours.

See service details

  • Web systems and applications

    From corporate sites to internal systems and SaaS. Built on Next.js, React and Astro with SEO and performance designed in.

    • Next.js
    • React
    • Astro
    • TypeScript

  • Mobile apps

    iOS and Android from one Flutter codebase. Location, maps, chat and payments, implemented with what we learned building our own apps.

    • Flutter
    • iOS
    • Android

  • Cloud and serverless platforms

    AWS-centred architectures combining Lambda, API Gateway, DynamoDB, S3 / CloudFront and Cognito for low cost and easy operation.

    • AWS
    • Lambda
    • CloudFront
    • Terraform / CDK

  • AI and LLM integration

    Conversational assistants, RAG, structured extraction and workflow automation on Amazon Bedrock, Claude and Gemini, from requirements to implementation and evaluation.

    • Amazon Bedrock
    • Claude
    • RAG
    • Structured Output

  • Multilingual and cross-border products

    Three-language design, hreflang and regional routing, translation workflows and multilingual SEO. We help you launch for users outside Japan or outside Japanese.

    • i18n
    • Multilingual SEO
    • Edge routing

  • Data pipelines and search

    Collecting data from APIs and the web, cleaning it, labelling it with LLMs and building search indexes. Infrastructure that turns data into value.

    • Python
    • OpenSearch
    • ETL

  • E-commerce, payments and booking

    Stripe subscriptions, Japan-specific payment methods (konbini, PayPay, LINE Pay), and booking and inventory systems.

    • Stripe
    • Booking
    • Subscriptions

  • Technical advisory and DX

    Technology selection, architecture review, building a development team, and improvement plans for existing systems. We work between management and engineering.

    • Architecture
    • Tech selection
    • Advisory

Stack

What we actually use in production

Frontend

  • Next.js
  • React
  • Astro
  • TypeScript
  • Tailwind CSS
  • Flutter

Backend

  • Python
  • FastAPI
  • Node.js
  • PostgreSQL / PostGIS
  • Redis
  • Prisma

Cloud

  • AWS Lambda
  • API Gateway
  • S3 / CloudFront
  • DynamoDB
  • Cognito
  • Supabase

AI / Data

  • Amazon Bedrock
  • Claude
  • Gemini
  • OpenSearch
  • Scrapy
  • Playwright

Process

How we work

The same team stays with you from the first conversation to operations.

  1. 1

    Discovery

    We listen to the problem, goals, budget range and deadline, and sort out together what is really needed. The first consultation is free.

  2. 2

    Requirements and design

    We narrow the scope and present screen, data and infrastructure design with a schedule and an estimate.

  3. 3

    Build

    We show working software in short cycles and adapt to changes along the way.

  4. 4

    Test and release

    Automated tests, performance and security checks, then production, with CI/CD in place.

  5. 5

    Operate and improve

    Monitoring and logging set up, then continuous improvement based on usage data. Maintenance contracts and advisory retainers are available.

FAQ

Frequently asked questions

Can we come to you with a small project or just a question?

Yes. Technology advice, improving an existing site, a few weeks of prototyping: we take on small engagements. Just get in touch.

How much does it cost?

It depends heavily on scope, so we give an estimate after the first conversation. We often recommend starting small and expanding in stages.

Can we work in English or Chinese?

Yes. We communicate in Japanese, English and Chinese, and work smoothly with overseas offices and international teams.

Do you handle operations and maintenance after delivery?

Yes. As a team that runs its own products, we offer ongoing support including monitoring, incident response and feature improvements.

We want to use AI but do not know where to start.

We look at where your team spends time or struggles with decisions, and identify where AI will help. We recommend a small proof of concept first to confirm the impact.

Let's talk about what you want to build.

An idea on a napkin or an existing system that needs work, both are welcome. Reach out in Japanese, English or Chinese.

Contact usSee products