Haeminway haemin/way
한국어
한국어

HAEMINWAY DEV

Automation and apps
for your work.

I build Google Sheets automations, simple mobile web apps, academy tools and short motion promos. Try the demos to see how they actually work.

Tell me the task Try the demos
Change one status and the row recolours and drafts the pickup email. Real Google Sheets, made-up bakery.

DEMOS

Small apps you can try

Only self-made public demos and separate fictional-data rebuilds are shown here.

Habit Streak

Check in daily, see each habit's streak calendar, compare a fictional friends board and save a share card. No login; stays on your device.

Live demo ↗

Quote & Invoice

Write a quote, send it, turn it into an invoice, mark it paid, then print or save a PDF. Fictional clients; no login; stays on your device.

Live demo ↗

Tap Ledger

Review and save an expense, see monthly spending, scan a receipt and confirm its amount, then export CSV or print. Fictional data; no login; stays on your device.

Live demo ↗

VIDEO

See it working

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Let the script wake itself up.

Edits, timers, form submissions. Three ways to start.

Music credit

Kevin MacLeod — Shiny Tech · CC BY 4.0

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Copy. Paste. What broke?

Three spreadsheet mistakes worth checking.

Music credit

WinnieTheMoog — Street Trap · CC BY 4.0

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One form. Fewer tabs.

Follow a form-to-report workflow.

Music credit

Kevin MacLeod — Enter the Party · CC BY 4.0

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Small screen. Big problems.

Three mobile bugs, and what fixes them.

Music credit

Ross Bugden — Black Heat (2026 Mix) · CC BY 4.0

SERVICES

Services

Also Small AI-assisted toolsDesktop setup

START SMALL

Start with one workflow

Starting from US$20 for one workflow

Delivered 3 days after requirements and access are ready, with one revision inside the agreed scope.

For larger work: US$30/h, with scope agreed in writing.

Extra workflows, data migration, paid APIs and ongoing support are a separate scope and quoted separately.

About this service

CASES

Selected work

All past work →

HOW IT GOES

Scope → build → check → handover

  1. 01

    Scope

    You show me the task; I write down what the tool will and won't do before anything is built.

  2. 02

    Build

    I build it inside your Google Workspace or as a small web app, whichever we agreed.

  3. 03

    Check

    You run it against the agreed scope. The pilot includes one revision.

  4. 04

    Handover

    Files, source and a short usage note move to your account.

DEV LOG

Notes from building small tools

Sheets, Apps Script and simple PWAs: what worked, and the bits that broke.

XLOOKUP vs VLOOKUP in Google Sheets: the 2-minute version

Lookups I ran in a real Google Sheet: where VLOOKUP quietly returns the wrong value, and the XLOOKUP version that doesn't.

Tap Ledger: log a coffee in two taps, total it in Sheets

A small expense app with presets, a month view and on-device receipt reading. Export to CSV and rebuild the same monthly totals in Google Sheets with SUMIFS.

A habit tracker that can leave the app: check-ins to CSV

Try Habit Streak, export a dated CSV, and count check-ins in Google Sheets. Fictional friends, local storage, and a clear boundary between export and sync.

Your Dashboard Refreshed. Did Its Source Data?

Separate page refresh time from source freshness. A fictional inventory example, timestamp contract, and failure drills keep old numbers from appearing current.

Bad Form Auto-Replies Damage Customer Trust

When form auto-replies damage customer trust, and what response rules should be set before automation.

ChatGPT API Costs Quietly Leak Money If You Do Not Count Them

Why ChatGPT API bills quietly grow, and how token tracking, caching, retries, and model routing keep them under control.
Full dev log →

Send the task that repeats most.

One sentence is enough — I reply with a written scope and price.

Contact me