Free Reservation System for Thai Guesthouses
One calendar for every booking: Agoda, Booking.com, Airbnb, LINE, WhatsApp, phone calls and walk-ins. No double bookings. No missed reservations. Check-in, room status, a bill with service charge and VAT where you need it, and daily reports. Free. No subscription, no trial period.
OnlineHotelier PMS is a free hotel reservation system for Thai guesthouses, homestays, villas, hostels and small resorts. It puts every booking in one calendar: Agoda, Booking.com, Airbnb, LINE, WhatsApp, phone and walk-in. Check-in, room status, housekeeping, bills with Thai VAT and service charge where you need them, and daily reports are all included at no cost. The optional paid add-on is the channel manager, which syncs availability across OTAs automatically.
OnlineHotelier PMS at a glance
| Product | OnlineHotelier PMS, a free cloud hotel reservation and management system |
|---|---|
| Price | Free. No subscription, no trial period |
| Who it is for | Guesthouses, homestays, villas, hostels and small resorts in Thailand with limited inventory |
| Local tax handling | Set your service charge and 7% VAT (Thailand's current rate, extended through 30 September 2027). The bill calculates automatically |
| Paid add-on | Channel manager that syncs availability and rates to Agoda, Booking.com, Airbnb and other OTAs. Pricing on WhatsApp |
| Runs on | Any web browser on a phone, tablet or laptop. Nothing to install |
| How to start | Sign up online, or message us on WhatsApp for guided setup |
One calendar for every booking source
You run a small guesthouse in Chiang Mai. An Agoda booking comes in for Room 3 on Friday night. Five minutes later, a message arrives on LINE: someone wants the same room on the same night. You check your notebook. Or your phone. Or both. A mistake is easy to make.
That is the problem the OnlineHotelier calendar solves. Every booking lives in one place, whatever its source:
- Agoda, Booking.com and Airbnb (via the channel manager add-on, or entered manually)
- LINE messages and WhatsApp inquiries (entered at the front desk)
- Phone calls and walk-ins (entered directly)
- Direct bookings from your own site or social media
When a room is taken, the calendar shows it as blocked. No double booking. Nothing missed. If you add the channel manager add-on, an Agoda booking closes the room on Booking.com and Airbnb automatically.
LINE as a booking channel in Thailand: LINE is widely used by Thai travellers and international visitors to contact guesthouses directly, ask about availability and confirm bookings by message. Adding those bookings to the same calendar as your OTA reservations is how you keep everything in one place without a spreadsheet.
Check-in, room status, housekeeping and check-out
The calendar is one piece. The rest of the day-to-day runs here too.
Guest check-in
Record the guest's name, passport or ID number, nationality, and room on arrival. The system creates a guest folio (a running bill) from the moment they check in. Read our guide on the hotel check-in process for what to collect and why.
Room status
Mark rooms as occupied, vacant, dirty or clean after housekeeping. Front desk sees the update live so they know which rooms are ready for the next guest.
Housekeeping
Your housekeeper updates room status from their phone as they clean. No walkie-talkies, no calling reception. The room shows as clean the moment it is ready.
Guest check-out and bill
Post room charges, any extras, and the guest's payments to their folio. Review the bill, apply service charge and VAT, and print or share it at check-out. Done in one step.
Daily reports give you occupancy, average room rate and total revenue for the day. Your manager gets the numbers they need each morning without building them by hand.
Thai VAT, service charge and TM30
The PMS is configured for Thailand. You set your property's rates once and the bill calculates correctly every time.
VAT
Thailand's current VAT (Value Added Tax) rate is 7%. This is a reduced rate from the statutory 10%. Royal Decree No. 807, published in the Royal Gazette on 20 August 2026, extends the 7% rate through 30 September 2027. VAT applies to accommodation charges.
If your property's annual taxable revenue is below THB 1.8 million, VAT registration is not required. Above that threshold, you must register and charge VAT on your bills. Check with a local accountant if you are close to the threshold.
Service charge
Service charge is your own charge, not a government tax. Most hotels in Thailand set it at 10% of the room rate. Many small guesthouses charge none, and the PMS works either way. VAT is then calculated on the room rate plus the service charge combined.
Here is how a typical bill looks:
| Room rate (1 night) | THB 2,000 |
| Service charge (10%) | THB 200 |
| Subtotal | THB 2,200 |
| VAT (7% on THB 2,200) | THB 154 |
| Total payable | THB 2,354 |
The PMS calculates this automatically. You set the service charge percentage and the VAT rate once in the settings. Every bill comes out right.
Payments
Record how each guest paid: PromptPay, credit or debit card, bank transfer, or cash. The folio keeps a full payment history. Your daily report shows total collections by payment type.
TM30
Under Section 38 of the Immigration Act, hotels must report foreign guests to the local immigration office within 24 hours of arrival. The PMS records each guest's details at check-in. A guest-list export formatted for TM30 filing is available on request: message us on WhatsApp to have it set up for your property.
Property types across Thailand
The system is built for small properties. Wherever you are in Thailand, if your main job is keeping track of who is in which room on which night, this covers it.
Bangkok and Hua Hin guesthouses
Urban guesthouses and small hotels serving both domestic and international guests. A high check-in and check-out volume means a clean front desk system matters more than anywhere else.
Chiang Mai and Pai guesthouses
Small guesthouses and boutique homestays in the north: a mix of Agoda bookings, walk-ins and LINE messages from repeat Thai travellers. One calendar keeps it all in order.
Koh Tao and Koh Lanta dive resorts
Island properties with seasonal peaks and a mostly international guest mix. Agoda and Booking.com are the main OTA channels. Preventing double bookings during high season is the single biggest operational problem the calendar solves.
Phuket and Koh Samui villas
Private villas with a small number of units, long stays and a higher room rate. VAT and service charge on the bill are standard guest expectations. The PMS handles both.
Hostels
Hostels have beds, not just rooms. Whether you track by bed or by room, the calendar handles your inventory. Mixed dormitories and private rooms can both be set up.
Homestays
A family-run homestay with two or three rooms often has no system at all. A free tool that runs on a phone and takes a few minutes to sign up for is a big step up from a notebook.
Channel manager: for when you outgrow updating each OTA by hand
If you are on one or two OTAs and you update availability yourself after each booking, the free PMS is enough. Most small properties start here.
The channel manager add-on becomes useful when you are on three or more OTAs and a booking on one platform means you need to close the room on all the others. Doing that by hand is slow, and a missed update causes a double booking.
The add-on connects your PMS calendar directly to Agoda, Booking.com, Airbnb and other OTAs. When a booking arrives, all connected channels update automatically. Read our guide on what a channel manager does before deciding whether you need one.
The channel manager add-on is paid. Message us on WhatsApp and we will give you the current price for your property.