Design Engineer
Portfolio 2026

I design and build products people actually use, from AI agents to mobile apps.

Available for work

PRITESH CHAUHAN

Selected work

Selected work

  1. Surge Agent

    2026
    Role

    Founder: designed, built and launched it solo

    About

    An AI operator for B2B service companies that lives inside WhatsApp and LINE. It finds customers, sends quotes, takes deposits and chases payment. You just approve.

  4. 305HQ

    2026
    Role

    Designed and coded every part myself, in Cursor

    About

    The unofficial GTA VI toolkit I designed and built myself in Cursor: a spoiler-safe map, a Creator Studio for thumbnails, and an Assets Generator for game-ready 3D props.

  5. VTVL

    2022–2025
    Role

    Founding UX designer: research, UX, UI and design system

    About

    Personalized token management for web3: automated vesting schedules, on-chain tracking and instant token distribution.

  6. Vanguard

    2023
    Role

    Solo designer: research, UX and UI

    About

    A mobile investing experience designed to help working mums start investing, with goal-based plans and a new investment manager.

More experiments

infosparklabs@gmail.com
Surge Agent – Case study
Close
Win new contracts. Get every invoice paid.

Surge Agent

Surge finds customers, sends quotes, takes deposits and chases payment, all inside WhatsApp and LINE. No app to install, no dashboard to learn. You just approve.

Year
2026
Role
Founder: designed, built and launched it solo
A dentist in his clinic holds his phone while a LINE chat floats above it: the owner asks Surge to book a patient for tomorrow at 15:00, and Surge replies that it is booked
Overview

A sales and accounts team that lives in your chat

Surge is an AI operator for B2B service companies that win contracts and bill businesses monthly or by project. The owner texts it like a manager; it does the work and reports back in a line or two.

There is nothing to install. Owners scan a QR code, WhatsApp or LINE opens with the first message ready, and setup happens in the conversation. It works in English and Thai.

Who it’s for
  • Facility management
  • Building & M&E maintenance
  • Fit-out & construction
  • Commercial solar
  • Security services
  • IT managed services
  • Marketing agencies
  • Logistics & transport
The problem

Small businesses run on chat, and owners can’t keep up.

Customers and leads message on LINE and WhatsApp at all hours. Replies are slow or missed, work gets lost in chat threads, and follow-ups never happen. Quotes go unchased and invoices go unpaid.

Hiring an admin costs ฿12,000–18,000+ a month, too much for most small businesses. Existing tools are either chatbots that only answer FAQs, or software (CRMs, booking and invoicing apps) that needs setup, training and a laptop, which small owners don’t use.

Living in Bangkok, I see this problem first-hand. Owners run their whole business from LINE on their phone, and messages, quotes and payments slip through the cracks. Surge started from watching that happen.

A business owner at her desk smiling at her phone. A customer asks in Thai to view a room tomorrow at 14:00, and Surge replies that the viewing is booked
Thai launch visual: AI business assistant on LINE. Let Surge handle the work while you run the shop. A LINE notification reads: Done, booked for tomorrow at 14:00

Launch visuals for the Thai market.

Front door

One page, one tap, and you’re in the chat

The live site at surge.channel does one job: get an owner into the chat. Pick WhatsApp or LINE and the app opens with the first message ready. On a computer, a QR code hands off to the phone. The whole page switches between English and Thai.

surge.channel on a phone with WhatsApp selected: Start on WhatsApp
surge.channel on a phone in Thai with LINE selected: Open LINE
On a computer, surge.channel shows a QR code: scan with your phone's camera to start on LINE

Screenshots of the live site, surge.channel.

How it works

From a QR scan to a paid invoice, all in the chat

The owner and their customers never leave the chat apps they already use. Surge does the work in between and only stops to ask when money, terms or a final notice are involved.

The owner, in WhatsApp or LINE
  1. 01

    Scan the QR code: the chat opens with the first message ready

  2. 02

    Answer a few questions: prices, payment terms, who you sell to

  3. 03

    Surge finds customers and emails them as your business

  4. 04

    Big deal, discount or final notice?

    Owner taps to approveRoutine · Surge just does it

  5. 05

    Ask anything: “Who owes me money?”

The customer
  1. 01

    Gets a quote page from the business

  2. 02

    Accepts it by typing their name

  3. 03

    Pays the deposit with a PromptPay QR

  4. 04

    Gets polite reminders on weekdays and taps Paid, Pay on… or Problem

  5. 05

    Transfer matched to the invoice, including 3% withholding tax

Conversation design

The chat is the interface

Every feature had to work as plain language or a one-tap button, because there are no screens to design around. Owners speak to Surge the way they’d speak to an assistant.

Things you can say
  • “Find offices in Sathorn”
  • “Quote Somchai Condo ฿18,000 a month”
  • “Who owes me money?”
  • “ABC paid 48,500”
Getting paid, and what customers see
  1. 01

    Reminders that fit the relationship

    Before the due date, on the day and after. Polite, and on weekdays only. The owner decides before any final notice.

  2. 02

    One-tap replies for customers

    Customers tap Paid, Pay on… or Problem, so a chase becomes a status update.

  3. 03

    Payments matched for you

    Transfers are matched to invoices, including 3% withholding tax.

  4. 04

    Quotes and invoices that look like you

    A quote they accept by typing their name, a PromptPay QR for the deposit, and invoices with your company and bank details.

Channel constraints

Designing around WhatsApp’s 24-hour rule

After 24 hours of silence, WhatsApp only allows a short template update. Surge sends the short version, and when the person replies the full message arrives. On LINE, replies arrive in full at any time. People can reply STOP, or block the account, to stop messages.

Trust and control

Surge asks before it acts, and never guesses a price or term.

Built in
  1. 01

    You approve what matters

    Final notices, big deals, discounts, payments, bulk messages and deletes wait for the owner’s tap.

  2. 02

    Money goes straight to you

    Payments go straight to the business’s own account.

  3. 03

    Guarded replies

    Messages that try to trick the system are filtered, and replies that contain prices or promises are checked before they reach a customer.

  4. 04

    Private by default

    Data is encrypted in transit and at rest, kept separate per business, and never sold or used to train AI. Connected-app logins are AES-256 encrypted, and Surge never asks for passwords in chat.

Beyond the chat

The pages a chat link opens

Some things don’t fit in a chat bubble, so Surge sends a private link instead. Customers accept a quote by typing their name and pay the deposit by PromptPay. Owners connect their other apps and manage their plan, each one tap from the chat.

These are recordings of Surge’s own pages, running locally with a demo business.

A customer accepts a quote by typing their name, then pays the 30% deposit with a PromptPay QR.
The owner’s account: connect Gmail, Google Calendar, Xero and 1,000+ other apps.
Plan and credits: what’s left this month and how credits work.
How I built it

Designed and engineered as one system

Node.js and SQLite on a Hetzner VPS (Docker and Caddy), with the LINE Messaging API (rich menus), the WhatsApp Cloud API, and Resend for email. Google Gemini does the thinking: Flash-Lite for simple replies, Flash for most work, Pro for hard cases, with a plan, approve and execute task engine and a fact-check on every customer reply.

Quality is measured, not assumed: an evaluation suite plays synthetic businesses through real conversations, and each failure becomes the next fix.

258
evaluation runs
54
conversation scenarios
2
channels, in English and Thai

Source: Surge eval history, October 2026

Business model

Simple pricing, no card to start

Pricing
  1. 01

    Free for 7 days

    No card needed.

  2. 02

    £99 a month

    Includes 1,500 credits. Extra credits: 1,000 for £25, and they never expire.

  3. 03

    Core work is free

    Invoice reminders, quote pages and payments use no credits. Cancel any time.

Outcome

Live on WhatsApp and LINE, and focused on where the money is

Surge is live at surge.channel in English and Thai, with a free 7-day trial. The biggest lesson was focus: the first version tried to run every kind of small shop, and narrowing to B2B service companies, where the money sits in quotes and unpaid invoices, gave every feature one clear job. Next is putting it in front of its first businesses and measuring the time it saves them.

Next project Synclyst