ResDiary EPoS & Inventory Integrations for UK Operators

September 26, 2026

Written by: JJ Tan, Founder, Jelly

Key Takeaways

ResDiary acts as the booking layer. It manages reservations and guest data, while EPoS and inventory tools handle stock and costing.
The architecture has three layers: bookings in ResDiary, sales in the EPoS, and recipes and stock in inventory software. Inventory systems receive data from the EPoS.
ResDiary integrates with UK EPoS systems such as Zonal, Square, PowerEPoS, Access EPOS, H&L POS, SumUp POS and The Good Till. These links exchange reservation and spend data only.
API access for custom integrations uses bespoke pricing and a certification process. This route suits operators with development resource, not most 2–5 site groups.
Jelly provides a POS-fed inventory layer that connects natively to Square, EPOS Now, Toast and Lightspeed. It automates invoices, inventory and real-time menu profitability without a direct ResDiary link.

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The Three-Layer Model: ResDiary, EPoS And Inventory

ResDiary sits at the booking layer. It manages covers, table turns, reservations, guest profiles and deposits. Recipes, ingredient costs and stock depletion live elsewhere.

Each layer handles different data:

ResDiary (Layer 1): bookings, covers, table turns, guest profiles, deposits and booking history.
EPoS (Layer 2): orders, itemised checks, spend per booking, payment status and walk-in records.
Inventory (Layer 3): recipes, ingredient costs, stock depletion, gross profit, supplier pricing and dish-level margin.

The data flows in two directions. Bookings and covers data flows back from ResDiary to inform demand forecasting, such as how many covers are expected, when they arrive and across which services. In the other direction, EPoS sales data flows forward to deplete stock, update dish costs and generate margin reports. Crucially, the inventory layer never receives data directly from ResDiary. It receives data from the EPoS.

This architecture matters before you evaluate any integration. A direct ResDiary-to-inventory connection is uncommon. The EPoS acts as the bridge.

See How Jelly Bridges EPoS And Inventory

Which EPoS Systems Integrate With ResDiary In The UK?

Since the EPoS acts as the bridge between bookings and inventory, operators need to know which tills connect to ResDiary. ResDiary partners with over 70 hospitality systems, but most connections are booking-distribution or EPoS links rather than inventory links. The following are the documented UK EPoS partners and what each integration actually exchanges:

Zonal: EPoS integration documented by ResDiary, syncing reservations and table activity to the till.
Square: Native integration with Square for Restaurants Plus, syncing reservations, table status, orders and spend in real time. Guest name, party size, booking time and notes pass to Square. Running spend updates in ResDiary as items are added. Payment closes the booking and records the final total.
PowerEPoS/Triniteq: EPoS link for reservation and table synchronisation.
Access EPOS: Part of The Access Group alongside ResDiary, with API documentation on the Access Hospitality Developers Hub.
H&L POS: EPoS integration for reservation and spend data.
SumUp POS: Named in ResDiary's own comparison material as a UK EPoS partner.
The Good Till: Documented ResDiary integration that merges front-of-house table statuses with back-of-house sales.

None of these integrations pass inventory data. Each exchanges reservation, table status and spend data. The inventory layer remains separate and takes its feed from the EPoS.

ResDiary API Options And When They Fit

ResDiary documents four distinct API options. Each supports a different type of integration.

EPoS API: Built for EPoS partners to construct a bi-directional integration. It supports getting bookings for the current date, updating arrival and meal statuses, adding walk-ins, recording spend against a booking and recording an itemised check against a customer profile.
Data Extract API: Moves customer and booking data into an external database for reporting and marketing. It runs an initial import of past data, then daily API calls for new bookings, profiles and changes.
Webhooks: Sends automated messages when a specific event occurs in the diary, such as booking creation or cancellation, reservation date or time change, covers updated, customer profile created or marketing preferences updated.
Consumer API: Powers bespoke booking journeys, including searching availability, creating reservations, taking payment, cancelling and updating details.

API access uses bespoke commercial terms. It does not have a fixed monthly price, and operators must complete a certification and approval process. Access starts with a request to ResDiary support that outlines the intended use case. The team then confirms the cost based on that use case and requirements. Full API documentation sits within the Access Hospitality Developers Hub alongside Access EPOS, Access Collins and Access Evo Stock.

This route suits operators with in-house development resource or a vendor willing to build and maintain the integration. It is not plug-and-play for most 2–5 site operators. It also does not create an inventory system on its own. It creates a bookings and spend data feed that still needs a separate inventory layer.

Cost And Fit For UK Operators

ResDiary's published UK price list runs from £109 to £295 per month plus VAT, with a £99 setup fee. Tiers differ by booking volume. The entry tier allows 150 bookings per month. The next tier allows 450. The third tier allows 1,000. The top tier is unlimited.

Add-ons cost between £10 and £35 per month each. They cover SMS, POS and PMS integrations, gift vouchers, pre-orders and the phone module. POS integration sits as a £10 per month add-on rather than part of the base subscription. API access has bespoke pricing, so it sits on top of the booking subscription as an extra charge.

ResDiary is purpose-built for reservations. It is not a POS with a bolted-on booking module, so venues still need a separate till system. It fits operators who need complex yield management, multi-site cross-selling and deep booking analytics. It does not function as a stock control system, even when integrated.

ResDiary's GB terms default to an annual rolling contract that renews automatically unless the customer gives 90 days' written notice before the anniversary date. Operators should factor the full cost, including subscription, add-ons, API access and payment surcharges, before committing.

Using A POS-Fed Inventory Layer When Your Tool Is Not Listed

Many inventory tools, such as MarketMan, Fourth, S4labour, Apicbase, Sage or Xero, do not appear as direct ResDiary partners. Most multi-site operators sit in this position and still need a workable stock control setup.

The practical architecture in this case is a POS-fed inventory layer. Instead of connecting to ResDiary, the inventory system reads itemised sales directly from the EPoS the moment a transaction completes. It also reads ingredient costs from scanned supplier invoices. Because the EPoS already connects to ResDiary, the inventory layer can connect to the EPoS and receive everything it needs. ResDiary continues as the booking layer, and the inventory layer operates independently.

Jelly gives growing restaurants, pubs and hotels a straightforward way to manage food and beverage operations. It automates invoices, inventory and real-time menu profitability. Jelly connects natively to Square, EPOS Now, Toast and Lightspeed via real-time API, pulling item-level sales data as soon as a transaction completes. POS setup takes under five minutes. Jelly's POS-to-dish linking only surfaces items sold since the integration was connected, keeping the mapping clean and focused on current menu items.

Jelly also integrates with Xero for one-click invoice push, with Sage integration coming soon. Pricing is a flat rate of £129 per month per location with no variable per-user charge, which makes budgeting across a multi-site estate simpler.

Start With A Jelly Inventory Walkthrough

Demand Forecasting And Menu Availability

The most valuable integration opportunity appears where bookings data meets inventory data. Covers booked in ResDiary provide a clear demand signal. A Friday evening with 120 covers booked across two sittings tells the kitchen how much prep is required and which dishes must stay available.

That signal becomes more powerful when combined with live dish costing and sales mix data. Together, they create a forecasting loop that guides purchasing, prep and menu decisions.

Platforms such as Workfeed already use ResDiary reservation data via the Data Extract API to forecast demand and build staff rotas. They display total reservations per day, seated guests per hour and expected arrivals. The same covers data can guide purchasing decisions and prep levels when paired with an inventory layer that knows the cost and yield of every dish on the menu.

Jelly's Menu Engineering (Sales Mix) feature integrates with Square, EPOS Now, Toast and Lightspeed to show which dishes are most popular and which are most profitable. When operators read that data alongside ResDiary covers forecasts, they can base purchasing on what is likely to sell rather than last week's sales or a rough estimate. Dishes with tightening margins surface in real time, and price alerts flag supplier increases before they erode GP.

A Short Decision Checklist For UK Multi-Site Operators

Operators can use this checklist to choose a workable architecture:

Confirm which EPoS you run and whether it appears on ResDiary's documented partner list.
Decide whether you need bookings data, sales data or both to drive stock control, and identify which layer each comes from.
Assess whether you have development resource for the API route, or whether a POS-fed inventory layer fits better.
Check that your inventory tool can read itemised EPoS sales and scanned supplier invoices without a direct ResDiary connection.
Confirm the monthly cost per site across all layers, including booking subscription, add-ons, API access and inventory software, before signing.

Conclusion

ResDiary provides a powerful booking layer, while the EPoS and inventory tools handle sales and stock. The data required for stock control flows through the EPoS, not directly from ResDiary.

Jelly closes the gap as a POS-fed inventory layer. It connects natively to Square, EPOS Now, Toast and Lightspeed, reads itemised sales as transactions complete and scans supplier invoices automatically. It turns that data into live dish costing, price alerts and margin protection at a flat rate of £129 per month per location. This approach removes the need for a direct ResDiary integration, manual spreadsheets and slow monthly accountant reports.

Get A Demo Of Jelly's POS-Fed Inventory