DEV Community: Lawrence Locke

Turning messy Airbnb / Vrbo / Booking.com payout CSVs into per-property profit

Lawrence Locke — Sun, 21 Jun 2026 14:36:42 +0000

Hosts rarely have a single clean ledger. Revenue comes from one export, platform fees from another, and operating costs from a bank or card CSV. Each source uses different columns, currencies, fee structures, and date formats. HostPayout turns that pile into one per-property profit view. Here's the shape of the problem.

Four exports, four formats

Airbnb — payout CSVs: gross, host fee, taxes, adjustments, payout date
Vrbo — owner statements with their own column names
Booking.com — finance exports with commission and payout columns
Bank / card — free-form expense rows with no notion of "property"

None of them agree on headers, sign conventions (is a fee a negative number or a separate column?), currency, or how dates are written.

Step 1: normalize into one transaction model

Every row, from every file, maps onto the same record:

date — parsed to a real date regardless of source format
property — which unit it belongs to
type — income, platform fee, tax/adjustment, or expense
amount + currency — kept in the original currency

Getting sign conventions and currency right here is most of the battle: a "fee" is a negative amount in one export and a positive value in a separate column in another.

Step 2: assign to properties — and keep it editable

A bank CSV doesn't know which apartment a cleaning charge belongs to, so import isn't the end — it's a review step. You assign properties, fix anything miscategorized, and delete what doesn't belong before the numbers hit your reports. Rows stay editable afterward, so a mistake is a quick fix, not a locked-in error.

Step 3: roll up to monthly net profit per property

Once everything is normalized and assigned, the report is the easy part:

Income, platform fees, and expenses per property
Net profit per property, per month
A portfolio summary across all units

No workbook, no formulas to maintain — the same three-step loop every month.

Why not just connect the APIs?

Because CSV exports work in any country and currency, need no bank login or Plaid, and don't break when a platform changes its API. You upload a file you already have, review it, and see whether each property actually made money.

Try it with your own export: hostpayout.com.

Try HostPayout: Owner statement CSV tracking · Airbnb profit tracker · Booking.com profit tracker · Upload your CSV free

Why I built a CSV-first rental profit tracker — no Plaid, no bank login

Lawrence Locke — Sun, 21 Jun 2026 14:35:15 +0000

Most short-term-rental finance tools start the same way: connect your bank through Plaid, link your Airbnb account, grant a pile of OAuth scopes. If you're a host outside the US, or you just don't want to hand bank credentials to another SaaS, that's where the tool ends for you.

I wanted to see whether each property I run was actually making money — without any of that. So I built HostPayout to be CSV-first.

Start from the export you already have

Every platform already lets you download your numbers:

Airbnb — payout CSVs with host fees, taxes, and adjustments
Vrbo / Booking.com — owner statements and finance exports
Your bank or card — expense CSVs

You export the file, drag it in, and HostPayout does the rest. No account linking, no Plaid, no bank login.

Why CSV beats integrations (for this problem)

Works in any country and currency — not just US banks
No credentials shared — you only ever upload a file you already have
Nothing is locked — rows stay editable and deletable, so you can fix a miscategorized expense instead of living with it
Resilient — there's no integration to break when a platform changes its API

The workflow

Upload your CSV from a rental platform or your bank
Review transactions — assign properties, clean up expenses, fix anything unclear before saving
See real profit — income, expenses, and net profit by property, updated every month

That's the whole loop, and it's the same on every plan.

Free forever for the first 5 properties

The core import → review → report workflow is free for up to 5 properties, no credit card. If you outgrow that, paid tiers add more property room — and if paid access ever lapses, your existing data and reporting stay available.

Who it's for

Hosts and small operators who get revenue in one export, fees in another, and costs from a bank CSV — and just want one monthly view of whether each property is making money, without rebuilding a spreadsheet every month.

Try it with the export you already have: hostpayout.com.

Try HostPayout: Airbnb profit tracker · Vrbo expense tracking · Booking.com profit tracker · Try the CSV demo (no signup)

Building a self-updating .ics auction calendar from 150+ sources

Lawrence Locke — Sun, 21 Jun 2026 14:33:26 +0000

HammerAlert tracks upcoming auctions from 150+ houses and exposes them as a single calendar feed you can subscribe to in Apple Calendar, Google Calendar, or Outlook. Here's how the calendar side of it actually works.

The hard part isn't the calendar — it's the sources

Every auction house publishes its schedule differently: different page structures, date formats, time zones, category names, and languages. Before anything can land in a calendar, all of it has to be pulled in and normalized into one shape.

One schema for every sale

Each upcoming sale becomes a record with the same fields, no matter where it came from:

house — Christie's, Phillips, Bukowskis…
title — the sale name
category — jewellery, watches, modern & contemporary art…
region — UK, Europe, US, Asia & Pacific
start — start date/time, stored in UTC
url — link back to the house's own listing

Normalizing region, category, and time zone up front is what makes filtering and a clean calendar possible later.

A personal, tokenized .ics feed

Calendar apps don't authenticate against an API — they fetch a plain .ics URL on a schedule. So every signed-in user gets their own tokenized feed:

hammeralert.com/api/calendar/your-personal-token.ics

The token identifies the user and their preferences without a login, so the URL is safe to paste into a calendar app but still personal. The endpoint renders the filtered set of sales as standard iCalendar VEVENTs on each request.

Filtering happens server-side

Because the feed is generated per token, the user's saved preferences — categories, regions, specific houses — are applied when the .ics is built. The calendar app only ever sees the sales that matter to that person, not all 2,000+ upcoming lots.

Staying fresh automatically

Calendar clients re-fetch the feed periodically. When a house adds, moves, or cancels a sale, the next fetch reflects it — no re-importing, no manual sync. Add the URL once and it keeps itself up to date.

Takeaways

Normalize messy sources into one schema before you think about output
A tokenized .ics URL gives you personalization without an auth flow in the calendar client
Let the calendar app's own refresh cycle do your syncing

You can see it in action at hammeralert.com.

How I track upcoming auctions across 150+ houses in one calendar feed

Lawrence Locke — Sun, 21 Jun 2026 14:32:08 +0000

Anyone who follows art, watch, jewellery or design auctions runs into the same problem: the sales are spread across a hundred different auction-house websites. Christie's, Sotheby's, Phillips, Bonhams, Bukowskis, Dorotheum — each publishes its own schedule, in its own layout, on its own page. There's no shared calendar, so it's easy to find out about a sale the day after it closed.

I built HammerAlert to fix that.

One place for every house

HammerAlert tracks upcoming auctions across 150+ houses worldwide and lets you browse them by category, region, or house — no account needed. Thousands of upcoming sales sit in one consistent view instead of a hundred different ones.

Set your preferences once

When you sign in, you choose what you actually care about:

Categories — jewellery, watches, modern & contemporary art, prints, design…
Regions — UK, Europe, US, Asia & Pacific
Specific houses — follow only the ones you buy from

Everything else gets filtered out, so you're not drowning in sales you'll never bid on.

Keep it in your own calendar

This is the part I use most. Instead of another dashboard to remember to check, HammerAlert gives you a personal calendar feed:

hammeralert.com/api/calendar/your-personal-token.ics

Add that URL once to Apple Calendar, Google Calendar, or Outlook and your upcoming auctions show up next to everything else. When the schedule changes, the calendar updates on its own — no re-importing.

Alerts when timing matters

On top of the calendar there's a weekly email digest and per-auction alerts for the sales you don't want to miss as they get close.

Why one calendar beats a hundred tabs

No more checking individual house websites
One filtered view of the whole market
Auctions live in the calendar you already use
Updates follow automatically

If you track auctions for work or for a collection, browse the index first and build your own calendar here: hammeralert.com.