RentalBux vs. KEYPrime (Landmark)
Which MTD Software Is Better for UK Landlords?
Overall Winner: RentalBux
RentalBux RentalBux is the better MTD software for UK landlords and sole traders. It combines full Making Tax Digital compliance across UK property income, foreign property income, and self-employment income with comprehensive property management, automated bookkeeping, AI-driven expense categorisation, joint ownership profit-splitting, a free plan for single-property landlords until March 2028, and a modern cloud platform with native iOS and Android apps. KEYPrime (Landmark) is a long-established and powerful suite that serves a specialist niche — rural estates, farms, and agricultural landlords managing highly diversified property portfolios — but its complexity, quote-only pricing, lack of a mobile app, requirement for accounting knowledge, and absence of landlord-specific features such as automatic joint ownership splits and foreign property MTD support mean it falls short of RentalBux's all-round offering for the majority of UK landlords. For standard residential, HMO, buy-to-let, and mixed-income landlords, RentalBux is the clear choice.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and KEYPrime (Landmark) across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Software Type | Property/Landlord Platform | Rural Estate Accounting + Property Management Suite |
| Target Users | Landlords, Sole Traders, Letting Agents | Rural Estates, Agricultural Landlords, Land Agents, Farms |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | UK Property + Business income (agricultural/rural focus) |
| Free MTD Software Plan | Free until March 2028 (1 property) | No |
| MTD Quarterly Updates to HMRC | Yes | Yes |
| Final Declaration | Yes | Yes |
| Bank Reconciliation | Yes | Yes |
| Automated Bank Feeds | Yes | Yes |
| Invoice Creation | Yes | Yes |
| Receipt Capture (OCR) | Yes | No |
| Expense Auto-Categorisation | Coming soon | No |
| Property Portfolio Management | Yes | Yes |
| Tenant Management | Yes | Yes |
| Joint Ownership & Profit Sharing | Yes | Manual allocation via nominal mapping |
| Payroll | No | Yes |
| HMO Unit-Level Tracking | Yes | No |
| HMRC SA105 Box Pre-Mapping | Yes | No |
| Spreadsheet Import/Export | Yes | Yes |
| Platform | Web, iOS, Android | Windows Desktop |
| GDPR Compliant | Yes | Yes |
What Is RentalBux? What Is KEYPrime (Landmark)?
What Is RentalBux?
All-in-One MTD Software for Landlords and Sole Traders
RentalBux is an all-in-one property management, accounting, and Making Tax Digital compliance platform built specifically for UK landlords, letting agents, and self-employed individuals. Designed with direct input from accountants who specialise in property and sole trader tax, RentalBux covers everything from tenancy management and rent collection to full bookkeeping with a pre-configured chart of accounts tailored to the property sector.
RentalBux is fully HMRC-recognised for Making Tax Digital for Income Tax across all three qualifying income categories: UK property income, foreign property income, and self-employment. This makes it one of the only landlord-specific MTD software platforms that can handle a landlord who also runs a sole trader business, all from a single subscription.
A major differentiator is RentalBux's pricing model: single-property landlords can use the platform completely free until March 2028, making it one of the most affordable HMRC-approved MTD software options for landlords entering the MTD regime.
What Is KEYPrime (Landmark)?
Start managing your farm’s finances with ease
KEYPrime is a suite of accounting and property management software developed by Landmark Systems Ltd, a UK company headquartered in Pulborough, West Sussex. Landmark has been developing and supporting software for rural businesses, farms, and estates for over 30 years and holds a Royal Warrant — a mark of recognition as a supplier to the Royal Household that reflects its long-standing reputation in the UK rural sector.
The KEYPrime suite relevant to landlords comprises two linked products. KEYPrime Property is the property management module, handling tenant records, tenancy management, rent demands, service charges, metered utility recharges, compliance date reminders, and property-level reporting. It is designed for a wide variety of property types: residential lettings, commercial sites, agricultural tenancies, containers, caravan parks, shooting rights, and more. KEYPrime Accounts (available in Intro, Accounts, and Advanced tiers) is the accounting backbone — providing full double-entry bookkeeping, VAT submissions, and, as of version 14.5 (released December 2025), MTD for Income Tax Self Assessment with quarterly updates and the final declaration. The two products integrate directly, linking property-level income and expense data to the accounting system.
Strengths
- Free MTD software for single-property landlords until March 2028
- Handles sole trader + UK property + foreign property income in one platform
- Joint ownership with automatic profit-sharing split by ownership percentage
- Pre-built chart of accounts tailored for landlords and sole traders
- AI-powered expense auto-categorisation and OCR receipt capture
- Agent filing on behalf of landlords — ideal for accountants and letting agents
- Supports HMO properties with auto-created units
Strengths
- Over 30 years' experience serving UK rural estates, farms, and landlords
- Handles highly complex, mixed property portfolios: agricultural, commercial, residential, caravan parks, shooting
- Full double-entry accounting with accruals basis, fixed asset register, foreign currency
- Service charge management and metered utility recharging for tenants
- MTD ITSA quarterly updates and final declaration in KEYPrime Accounts v14.5+
- Client Accounting module for agents managing multiple landlords
- Multi-company Consolidator module for complex estate structures
- Payroll integration (KEY2Payroll)
- Royal Warrant holder — established reputation in UK rural sector
- UK-based support team with training available
- PC installation option for offline working
Limitations
- Newer to market compared to established platforms
- No yield or LTV investment analysis tools
- No MTD for VAT support yet
- Some advanced reporting features still in development
- Limited third-party app integrations
- No offline capability
- No tax liability forecasting feature currently
Limitations
- Pricing not published — requires sales consultation and quote
- No native iOS or Android mobile app
- Requires accounting knowledge to operate effectively
- Primarily designed for rural estates — less suited to standard urban buy-to-let landlords
- Joint ownership profit-splitting requires manual nominal mapping
- No native mobile app — tablet/phone access only via web-hosted option
- MTD ITSA is in KEYPrime Accounts, not KEYPrime Property — requires the accounts module
- No free plan or trial listed publicly
- No AI-powered expense categorisation (manual, with Dext/AutoEntry integration)
- Complex setup may require consultant assistance
- Foreign property income for MTD not confirmed as a separate supported category
Making Tax Digital Compliance
How RentalBux Handles MTD Compliance
RentalBux supports all three MTD qualifying income categories: sole trader income, UK property income, and foreign property income. This makes it suitable for landlords who also earn self-employment income, eliminating the need for separate software. Most accounts are pre-mapped to HMRC Self-Assessment boxes. RentalBux also supports agent filing, allowing accountants or letting agents to submit MTD returns on behalf of their landlord clients.
How KEYPrime (Landmark) Handles MTD for Landlords
MTD for Income Tax Self Assessment was introduced into the KEYPrime Accounts range in version 14.5 (released December 2025). Users access it via the HMRC menu in Ledgers within KEYPrime Accounts. The process requires: setting up taxable business entities (entering National Insurance number and linking to HMRC via Government Gateway); mapping each income and expenditure nominal in the chart of accounts to the appropriate Self Assessment category; reviewing transactions allocated to each taxable entity; and then submitting the four quarterly obligations and the Final Declaration for each taxable entity.
Landmark's own update notes confirm the system handles both quarterly submissions and a Final Declaration per taxable entity, with the category allocation based on the nominal mappings. KEYPrime Accounts is confirmed by Landmark as HMRC-approved for Making Tax Digital for Income Tax. MTD for VAT has been supported since 2019, when Landmark facilitated digital VAT submissions for over 7,000 companies using the KEYPrime range.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| HMRC Recognised (MTD ITSA) | Yes | Yes |
| MTD Quarterly Updates | Yes | Yes |
| Final Declaration | Yes | Yes |
| Digital Record Keeping | Yes | Yes |
| Digital Links Compliant | Yes | Yes |
| Sole Trader Income | Yes | Yes |
| UK Property Income | Yes | Yes |
| Foreign Property Income | Yes | No |
| Multiple Income Streams | Yes | No |
| Agent Filing on Behalf | Yes | Yes |
Winner: RentalBux for MTD accessibility; KEYPrime for established VAT and business accounting depth — RentalBux requires no manual configuration and covers all three MTD income types in a single free plan. KEYPrime Accounts offers MTD ITSA in its established accounting suite with a full chart of accounts and deep business accounting functionality, but requires manual nominal mapping and the accounts module alongside the property module.
Property Management
RentalBux: Property Management
RentalBux provides comprehensive property portfolio management with tenant management, rent tracking, property expense allocation, and support for multiple properties. A standout feature is its joint ownership and profit-sharing capability: landlords can define ownership percentages once, and RentalBux automatically splits rental income and expenses. RentalBux also supports HMO properties, automatically creating individual units.
KEYPrime Property: Estate and Agricultural Property Management
KEYPrime Property is designed for a far wider range of property types than any residential landlord platform. It manages residential properties, commercial sites, agricultural tenancies, containers, caravan parks, shooting rights, and more. Core features include tenant and tenancy management, automated rent demand generation, multi-tenancy service charge management (including bulk updates), metered utility recharging for tenants (via the Metering module), compliance date reminders for critical deadlines, document attachment across the system, and detailed financial and property reports for landlords and tenants. It also includes a Client Accounting module for agents managing multiple landlord clients within a single system.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Property Portfolio Management | Yes | Yes |
| Tenant Management | Yes | Yes |
| Rent Tracking | Yes | Yes |
| Property Expense Allocation | Yes | Yes |
| Multiple Property Support | Yes | Yes |
| HMO Property Support | Yes (auto-creates units) | Yes |
| Joint Ownership/Profit Sharing | Yes (auto-split by %) | Manual nominal mapping |
| Maintenance Tracking | No | No |
| Tenant Screening | No | No |
| Compliance Document Alerts | Yes | No |
| Arrears Tracking | No | Yes |
Winner: RentalBux for standard residential and BTL landlords. RentalBux wins on joint ownership automation, HMO setup speed, compliance alerts, and accessibility for standard residential landlords.
Bookkeeping, Accounting & Digital Record Keeping
RentalBux: Structured Accounting
RentalBux includes a pre-built chart of accounts specifically designed for landlords and sole traders, covering rental income, mortgage interest, insurance, property repairs, professional services, utilities, and tenant deposits. All accounts are pre-mapped to HMRC Self-Assessment boxes. The platform supports cash basis accounting, bank reconciliation, and journal entries.
KEYPrime Accounts: Full Double-Entry Accounting for Rural Businesses
KEYPrime Accounts (Intro, Accounts, and Advanced) is a comprehensive double-entry bookkeeping system designed for rural businesses of all sizes. It supports both cash basis and accruals basis accounting, a fully customisable chart of accounts, journal entries, fixed asset register with depreciation, foreign currency transactions, full VAT management (standard, cash, and flat rate), and a wide range of financial and management reports. The Advanced tier adds Sales Order Processing (SOP), Purchase Order Processing (POP), stock management, and enterprise-level analysis and budgeting. A Consolidator module allows multi-company reporting — essential for estate structures with multiple legal entities.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Cash Basis Accounting | Yes | Yes |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | Yes |
| Journal Entries | Yes | Yes |
| Bank Reconciliation | Yes | Yes |
| Automated Bank Feeds | Yes (Major UK banks) | Yes |
| Open Banking Integration | Yes | Yes |
| Double-Entry Bookkeeping | Yes | Yes |
| HMRC Box Pre-Mapping | Yes | No |
| Xero Integration | No | No |
| Spreadsheet Import/Export | Yes | Yes |
| Digital Record Storage | Yes | Yes |
Winner: RentalBux for landlord accessibility. RentalBux's landlord-pre-mapped accounts and native receipt capture make it more accessible for landlords without accounting backgrounds.
Invoicing, Expense Tracking
RentalBux: Expense Management
RentalBux includes OCR receipt capture, structured expense tracking with landlord-specific categories, auto-categorisation, invoice creation with customisable branding, and payment tracking with reminders.
KEYPrime: Automated Rent Demands, Service Charges and Document-Driven Entry
KEYPrime Property automates rent demand generation from configured tenancy schedules. Invoices are customisable with business logos via template layouts. Service charges can be processed for multiple tenancies simultaneously. The Metering module generates utility recharge invoices automatically from meter readings. For expense capture, KEYPrime integrates with Dext (formerly Receipt Bank) and AutoEntry — users can photograph invoices and receipts which are then imported into KEYPrime Accounts. This integration-based approach works well for accounting practices but requires a separate Dext/AutoEntry subscription.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Invoice Creation & Sending | Yes | Yes |
| Invoice Customisation/Branding | Yes | No |
| Online Payment Collection | Yes | No |
| Payment Tracking/Reminders | Yes | Yes |
| Expense Tracking | Yes | Yes |
| Receipt Capture (OCR/Photo) | Yes | No |
| Expense Categorisation | Yes | Yes |
| Automated Transaction Matching | Yes | Yes |
| Mileage Tracking | No | No |
| AI Auto-Categorisation | Coming soon | No |
Winner: RentalBux for receipt automation. RentalBux wins on native expense capture.
Reporting & Tax Forecasting
RentalBux: Formal Accounting Reports
RentalBux produces structured financial reports including profit & loss statements, balance sheets, journal reports, ledger reports, and trial balances. Smart categorisation helps ensure accuracy.
KEYPrime: Comprehensive Business and Property Reporting
KEYPrime Accounts and KEYPrime Property together produce an extensive reporting suite. Financial reports include profit & loss, balance sheet, trial balance, VAT reports, debtor and creditor ageing reports, and enterprise-level analysis. Property-specific reports include rent books, demands reports, tenancy reports, arrears analysis, and client statements for agents. The Consolidator module enables multi-company consolidated reporting for complex estate structures. Enterprise budgeting allows "what if" analysis. Advanced tier adds cashflow reports and detailed enterprise margin reporting.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Profit & Loss Report | Yes (formal) | Yes |
| Balance Sheet | Yes | Yes |
| Trial Balance | Yes | Yes |
| Dashboard/Overview | Yes | Yes |
| Real-Time Financial Data | Yes | Yes |
| Cash Flow Reporting | No | Yes |
| Tax Estimate/Forecast | Yes | Yes |
| AI-Powered Features | Coming soon | No |
Winner: Tie as both RentalBux and KEYPrime offer real-time financial data, tax estimation and designated dashboard for overview.
Collaboration & Mobile Apps
RentalBux's Collaborative Features
RentalBux enables agent filing, which gives accountants and letting agents the ability to submit directly on a landlord's behalf.
KEYPrime's Collaborative Features
KEYPrime is available as a Windows PC installation or as a web-hosted solution. PC installation offers offline working capability — valuable for rural estate offices with unreliable connectivity. The web-hosted option enables remote access from office and tablet devices. There is no dedicated native iOS or Android mobile app, though the web-hosted version can be accessed via mobile browsers. Accountant and consultant licences are available, allowing professionals to access client data to assist with final accounts and analysis. The KEYPrime Accounts system supports HMRC agent feeds, allowing the accountant to authorise submissions on behalf of clients.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Accountant/Advisor Portal | Yes | Yes |
| Multi-User Access | Yes | Yes |
| Agent Filing on Behalf | Yes | Yes |
| Bank Integration | Yes | Yes |
| Platform | iOS, Android | Windows Desktop |
| Web Browser Access | Yes | No |
| FCA Regulated | Yes | Yes |
| GDPR Compliant | Yes | Yes |
Winner: RentalBux for mobile and cloud accessibility. RentalBux's native mobile apps and cloud-first design are more convenient for landlords managing properties on the go.
Ease of Use, Support & Security
RentalBux: Guided Workflows
RentalBux uses guided workflows, clear dashboards, and no accounting jargon. The platform offers phone support, email/chat support, and a help centre with guides and knowledge base articles.
KEYPrime's Ease of Use
KEYPrime is a professional accounting system designed for users with bookkeeping knowledge. The AccountingWEB community notes that it requires understanding of debits and credits to operate effectively, and initial setup — particularly chart of accounts mapping and MTD nominal configuration — benefits from consultant or accountant support. However, once configured correctly, users report significant time savings on routine tasks such as rent demand generation.
| Feature | RentalBux | KEYPrime (Landmark) |
|---|---|---|
| Phone Support | Yes | Yes |
| Chat Support | Yes | No |
| Email Support | Yes | Yes |
| Help Centre/Knowledge Base | Yes | Yes |
| FCA Regulated | Yes | Yes |
| Enterprise-Grade Security | Yes | No |
RentalBux Features
Sole Trader Income Support for MTD
RentalBux is one of the few landlord-focused MTD software platforms that supports self-employment income alongside UK and foreign property income within a single account. Landlords who also run a trade, consultancy, or freelance business can manage all quarterly submissions from one dashboard. Landlord Studio covers property income only.
Custom Chart of Accounts for Landlords
A property-tailored chart of accounts covering rental income, mortgage interest, insurance, repairs, utilities, letting agent fees, and more — all pre-mapped to HMRC Self-Assessment boxes. No setup required; the system is ready to use from day one. Landlord Studio has no equivalent.
Agent Filing on Behalf of Landlords
Letting agents and accountants can submit MTD quarterly updates and the Final Declaration on behalf of landlord clients directly from the platform. Landlord Studio allows accountant access but does not support submission on the landlord's behalf.
Branded Invoice Creation
Invoice creation with customisable branding for service charges and commercial landlords. Not available in Landlord Studio.
AI-Powered OCR Receipt Capture with Auto-Categorisation (Coming soon)
RentalBux's AI will read uploaded receipts and categorise the expense automatically against the pre-built chart of accounts. Landlord Studio's Smart Scan extracts dates and amounts but does not include AI-driven expense categorisation.
Formal Accounting Reports
Balance sheet, trial balance, ledger reports, and journal reports. Landlord Studio does not produce these natively.
Free Plan Including MTD Submissions Until March 2028
RentalBux's free single-property plan includes MTD quarterly submissions. Landlord Studio's free GO plan covers property management for up to three units but requires a paid PRO plan (from £12/month) to access MTD submission functionality.
Unique Features Only KEYPrime (Landmark) Offers
Agricultural and Diversified Rural Property Types
KEYPrime Property supports agricultural tenancies, caravan parks, shooting rights, containers, and a wide range of rural property types.
Service Charge Management
Multi-tenancy service charge creation, bulk updates across tenancies sharing the same Item code, and pro-rata invoicing on tenancy end.
Metered Utility Recharging (Metering Module)
Record utility meter readings for multiple meter types and automatically generate recharge invoices for tenants at varying rates. A significant time-saver for industrial, commercial, and caravan park landlords.
Full Accruals Basis Accounting
KEYPrime supports accruals basis as well as cash basis — essential for businesses with complex financial reporting obligations.
Fixed Asset Register with Depreciation
Track business assets, calculate depreciation, and manage write-offs within the accounting system.
Multi-Company Consolidation (Consolidator Module)
Consolidate financial reporting across multiple companies within a single estate structure. Essential for complex rural estates with multiple legal entities.
Client Accounting Module for Property Agents
Manage multiple individual landlords within an overall client account — generating service charges, reconciling accounts per landlord, and producing client statements.
Payroll Integration (KEY2Payroll)
Seamlessly connect bookkeeping to payroll for estate employees.
Foreign Currency Accounting
Handle transactions in multiple currencies — relevant for estates with international suppliers or tenants.
Sales and Purchase Order Processing (Advanced Tier)
Full SOP and POP for businesses with significant trade activity alongside property management.
Offline PC Installation
Work without an internet connection — important for rural estate offices in areas with poor connectivity.
30+ Years of Specialist Rural Sector Heritage and Royal Warrant
Landmark Systems has served the UK rural sector for over 30 years, holds a Royal Warrant, and is the NFU's sole recommended farm software supplier — a depth of sector-specific trust and expertise that no newer platform can match.
Who Should Choose RentalBux?
RentalBux is a strong fit if you:
Landlords with Mixed Income Streams
If you earn from both property and self-employment, RentalBux handles sole trader income alongside UK and foreign property income in a single MTD-compliant platform.
Joint Owners and Family Portfolios
The automated profit-sharing split is a standout feature. Define ownership percentages once and RentalBux calculates each owner's share automatically.
Budget-Conscious Landlords Entering MTD
Free MTD software for single-property landlords until March 2028, with no upfront commitment.
Landlords Who Want Proper Accounting Structure
Chart of accounts, journal entries, profit & loss, balance sheet, and trial balance give RentalBux a structured accounting foundation.
Accountants and Letting Agents
Agent filing on behalf, multi-user access, and spreadsheet import make RentalBux practical for professionals managing multiple landlord portfolios.
Commercial Landlords and HMO Owners
Invoice creation with branding for service charges, plus automatic HMO unit creation and tenant management.
Who Should Choose KEYPrime (Landmark)?
KEYPrime (Landmark) is the better choice for:
Rural Estates, Farms, and Agricultural Landlords
If your property portfolio includes agricultural tenancies, grazing rights, shooting, caravan parks, or diversified rural enterprises alongside residential properties, KEYPrime Property's specialist rural property types are unmatched.
Estate Managers and Land Agents with Complex Mixed Portfolios
Agents managing properties for multiple landlord clients within a client accounting structure, or estates with separate legal entities requiring multi-company consolidated reporting, will find KEYPrime's depth essential.
Large Estates with Commercial and Service Charge Properties
Any landlord charging service charges across multiple tenancies — particularly for commercial sites or managed estates — will benefit from KEYPrime Property's service charge management, which has no equivalent in standard landlord platforms.
Agricultural or Rural Businesses Already Using KEYPrime for Farm Accounts
If you already use KEYPrime Intro, Accounts, or Advanced for your farming business, adding KEYPrime Property for rental income tracking integrates natively with existing financial records.
Landlords with Multiple Business Entities Requiring Consolidation
Where a rural estate operates multiple companies and needs consolidated reporting across all entities, KEYPrime's Consolidator module is purpose-built for this complexity.
NFU Members Seeking a Recommended and Discounted Solution
As the NFU's sole recommended farm software supplier, Landmark offers NFU member discounts and a sector-specific reputation that is difficult to replicate.