RentalBux vs. 123 e-Filing
Which MTD Software Is Better for UK Landlords and Sole Traders?
Overall Winner: RentalBux
RentalBux is the more complete MTD solution for 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, and a free plan for single-property landlords until March 2028. 123 e-Filing is a useful option for individuals who need to file Self Assessment tax returns (SA100 and SA800) alongside MTD VAT and ITSA bridging submissions, and who prefer a pay-per-submission model over an annual subscription. However, its per-submission pricing model, limited MTD ITSA track record relative to established bridging tools, mixed Trustpilot reviews, and complete absence of bookkeeping, property management, or reporting features make it a narrow filing tool rather than a platform for landlords who need comprehensive MTD compliance.
At-a-Glance MTD Software Comparison
Key differences between RentalBux and 123 e-Filing across MTD compliance, property management, bookkeeping, pricing, and landlord-specific features.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Software Type | Property/Landlord Platform | Web-Based Tax Filing & MTD Bridging Tool |
| Target Users | Landlords, Sole Traders, Letting Agents | Individuals, Sole Traders, Landlords, Expats |
| Income Sources Supported | Sole Trader + UK Property + Foreign Property | Sole Trader + UK Property (via Excel bridging) |
| Free MTD Software Plan | Free until March 2028 (1 property) | Free to register and test; charge per submission |
| MTD Quarterly Updates to HMRC | Yes | Yes |
| Final Declaration | Yes | Yes |
| Bank Reconciliation | Yes | No |
| Automated Bank Feeds | Yes | No |
| Invoice Creation | Yes | No |
| Receipt Capture (OCR) | Yes | No |
| Expense Auto-Categorisation | Coming soon | No |
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Joint Ownership & Profit Sharing | Yes | No |
| Payroll | No | No |
| HMO Unit-Level Tracking | Yes | No |
| HMRC SA105 Box Pre-Mapping | Yes | No |
| Spreadsheet Import/Export | Yes | Yes |
| Platform | Web, iOS, Android | Web browser only |
| GDPR Compliant | Yes | Yes |
What Is RentalBux? What Is 123 e-Filing?
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 123 e-Filing?
123 e-Filing (123efiling.co.uk) is a UK-based online tax filing service registered in England and Wales (Company Registration No. 10252005), based in Bolton, Greater Manchester. It is HMRC-recognised for Self Assessment personal tax returns (SA100), partnership tax returns (SA800), and Making Tax Digital for VAT. The platform also provides an MTD ITSA bridging tool for self-employed individuals and landlords. Its core differentiator from other bridging tools is its broader tax return offering: users who need to file Self Assessment returns alongside MTD obligations can do both from the same platform.
123 e-Filing operates on a pay-per-submission model, with no annual subscription. Users register for free and can test the software before paying, with charges applied at the point of submission from £2.99 + VAT. Self Assessment returns are charged separately, from approximately £14.99 + VAT per return, with an assisted service option available for those who want an accountant to review or complete their filing. For MTD ITSA, users extract their income and expense data from an Excel spreadsheet (2010 or later) and upload it via the 123 e-Filing website for quarterly submission to HMRC.
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
- HMRC-recognised for SA100, SA800, MTD VAT and MTD ITSA
- Pay-per-submission — no annual subscription commitment
- Self Assessment returns supported — a feature most bridging tools lack
- Assisted filing service available for expats and complex returns
- Supports all SA100 supplementary forms including foreign income
- Free to register and test before paying
- No setup, monthly, or hidden charges
- Online chat support available
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
- Bridging only for MTD — does not create or maintain digital records
- No property management, tenant management, or rent tracking
- No bank feeds, AI categorisation, or receipt capture
- Charges apply per submission, including failed ones in some cases
- Amendments require a separate paid submission (approx. £15+)
- Excel 2010+ required; does not support Google Sheets or older Excel
- Mixed Trustpilot reviews (~3.5 stars, 113 reviews)
- No phone support; chat and email only
- No mobile app; browser-based only
- No formal accounting reports, balance sheet, or P&L
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 123 e-Filing Handles MTD Compliance
123 e-Filing is HMRC-recognised for MTD ITSA as a bridging tool for self-employed individuals and landlords. The MTD ITSA workflow requires users to extract their income and expenses from an Excel spreadsheet (version 2010 or later) and upload that file to the 123 e-Filing platform for quarterly submission to HMRC. The platform does not create or maintain the underlying digital records — that remains the user's responsibility. 123 e-Filing also supports MTD VAT via the same spreadsheet upload mechanism, and its Self Assessment tax return filing (SA100 and SA800) is its most established and widely reviewed product. The MTD ITSA offering is newer and less documented in third-party reviews than its SA100 product.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| HMRC Recognised (MTD ITSA) | Yes | Yes |
| MTD Quarterly Updates | Yes | Yes |
| Final Declaration | Yes | Yes |
| Digital Record Keeping | Yes | No |
| 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 ITSA — RentalBux creates and maintains compliant digital records automatically and covers all three MTD income types. 123 e-Filing has a unique advantage on Self Assessment returns (SA100/SA800) and MTD VAT.
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.
123 e-Filing: No Property Management Features
123 e-Filing has no property management functionality whatsoever. It is a tax filing and bridging submission interface only. It does not track tenancies, manage rent, record compliance document deadlines, allocate expenses to individual properties, or provide any landlord-specific workflows. All property administration must be managed in separate software or spreadsheets. For landlords who already use dedicated property management software and simply need a submission tool, this may be acceptable — but it means 123 e-Filing cannot serve as a single platform for a landlord's digital needs.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Property Portfolio Management | Yes | No |
| Tenant Management | Yes | No |
| Rent Tracking | Yes | No |
| Property Expense Allocation | Yes | No |
| Multiple Property Support | Yes | No |
| HMO Property Support | Yes (auto-creates units) | No |
| Joint Ownership/Profit Sharing | Yes (auto-split by %) | No |
| Maintenance Tracking | No | No |
| Tenant Screening | No | No |
| Compliance Document Alerts | Yes | No |
| Arrears Tracking | No | No |
Winner: RentalBux — 123 e-Filing has no property management features. RentalBux provides a full landlord management suite including tenancy management, rent tracking, HMO support, joint ownership profit-splitting, and compliance alerts.
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.
123 e-Filing: No Bookkeeping — Submission Interface Only
123 e-Filing performs no bookkeeping functions. It is a web interface for submitting tax data to HMRC. For MTD ITSA, the user's Excel spreadsheet is their digital record — 123 e-Filing's sole MTD function is to provide the submission channel for that data. For Self Assessment returns, users enter data directly into the online forms, which mirror the structure of HMRC's own SA100 and SA800 forms. There are no bank feeds, no chart of accounts, no journal entries, and no ongoing digital record management of any kind.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Cash Basis Accounting | Yes | No |
| Chart of Accounts (Pre-built, Landlord-Tailored) | Yes (pre-built + custom) | No |
| Journal Entries | Yes | No |
| Bank Reconciliation | Yes | No |
| Automated Bank Feeds | Yes (Major UK banks) | No |
| Open Banking Integration | Yes | No |
| Double-Entry Bookkeeping | Yes | No |
| HMRC Box Pre-Mapping | Yes | No |
| Xero Integration | No | No |
| Spreadsheet Import/Export | Yes | No |
| Digital Record Storage | Yes | No |
Winner: RentalBux — 123 e-Filing has no bookkeeping capability whatsoever. RentalBux provides a complete landlord-tailored accounting backbone. For landlords who need HMRC-compliant digital records — not just a submission mechanism — RentalBux is the only viable choice between the two platforms.
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.
123 e-Filing: No Expense Tracking or Invoicing Features
123 e-Filing has no expense tracking, receipt capture, invoice creation, or automation features of any kind. It is a submission interface, not a bookkeeping tool. For MTD ITSA purposes, all expense recording and categorisation takes place in the user's own Excel spreadsheet before the file is uploaded for submission. 123 e-Filing does not assist in maximising allowable deductions, flagging uncategorised expenses, or reducing manual data entry time. Users are responsible for the accuracy and completeness of their records entirely independently of the platform.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Invoice Creation & Sending | Yes | No |
| Invoice Customisation/Branding | Yes | No |
| Online Payment Collection | Yes | No |
| Payment Tracking/Reminders | Yes | No |
| Expense Tracking | Yes | No |
| Receipt Capture (OCR/Photo) | Yes | No |
| Expense Categorisation | Yes | No |
| Automated Transaction Matching | Yes | No |
| Mileage Tracking | No | No |
| AI Auto-Categorisation | Coming soon | No |
Winner: RentalBux — 123 e-Filing has no invoicing, expense tracking, or automation features. RentalBux's AI-powered OCR, automatic expense categorisation, and branded invoicing give it a decisive advantage for landlords who want to maximise allowable deductions under MTD.
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.
123 e-Filing: No Reporting Features
123 e-Filing produces no financial reports. Once a return or quarterly update has been submitted, the platform's function is complete. There is no dashboard showing portfolio performance, no profit and loss output, no tax estimate, and no financial overview. Users can download a PDF copy of their submitted return for their own records, but this is a record of submission rather than a financial report. All analysis, reporting, and tax planning must take place outside the 123 e-Filing platform, in the user's own spreadsheet or with their accountant.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Profit & Loss Report | Yes (formal) | No |
| Balance Sheet | Yes | No |
| Trial Balance | Yes | No |
| Dashboard/Overview | Yes | No |
| Real-Time Financial Data | Yes | No |
| Cash Flow Reporting | No | No |
| Tax Estimate/Forecast | Yes | No |
| AI-Powered Features | Coming soon | No |
Winner: RentalBux — 123 e-Filing produces no financial reports. RentalBux leads comprehensively across all reporting metrics. The only document output 123 e-Filing provides is a PDF copy of the submitted return itself.
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.
123 e-Filing: Agent Packages and Assisted Service, Limited Collaboration
123 e-Filing offers agent packages for accountants who file on behalf of clients, and an assisted service option where users can pay for their return to be reviewed or completed by a 123 e-Filing tax professional — a feature that goes beyond what most bridging tools offer. However, the platform does not provide real-time shared access between a landlord and their external accountant in the way that a cloud platform would. The MTD ITSA workflow is account-based and submission-focused rather than collaborative. The platform is web-based and browser-accessible on any device, but there is no dedicated mobile app, and the MTD ITSA bridging workflow requires Excel 2010 or later, which limits mobile use for submissions.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Accountant/Advisor Portal | Yes | Yes |
| Multi-User Access | Yes | Limited (agent account-based) |
| Agent Filing on Behalf | Yes | Yes |
| Bank Integration | Yes | No |
| Platform | iOS, Android | Web browser only |
| Web Browser Access | Yes | Yes |
| FCA Regulated | Yes | No |
| GDPR Compliant | Yes | No |
Winner: RentalBux for ongoing collaboration. 123 e-Filing's assisted filing service is a genuine differentiator for individuals who want a tax professional to review their return — a capability RentalBux does not offer.
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.
123 e-Filing: Simple Forms with Mixed Customer Service Feedback
123 e-Filing's user interface is built around the structure of HMRC's own tax forms — familiar to anyone who has filed a Self Assessment return before. For straightforward returns and MTD bridging, users consistently report a quick and simple experience. However, Trustpilot reviews reveal recurring concerns about the platform's customer service approach, particularly around charges applied to failed or amended submissions. Some reviewers report difficulty resolving HMRC gateway credential issues with chat support, and note that amendments require paying the full submission fee again. Support is provided via live chat and email; there is no phone support. Overall the Trustpilot rating sits around 3.5 stars from approximately 113 reviews — notably lower than comparable HMRC-recognised bridging tools. 123 e-Filing is GDPR-compliant and its systems meet HMRC's technical requirements as a recognised software provider.
| Feature | RentalBux | 123 e-Filing |
|---|---|---|
| Phone Support | Yes | No |
| Chat Support | Yes | Yes |
| Email Support | Yes | Yes |
| Help Centre/Knowledge Base | Yes | Basic guidance notes |
| FCA Regulated | Yes | No |
| 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 123 e-Filing Offers
Self Assessment tax return filing (SA100 and SA800)
123 e-Filing is HMRC-recognised for personal and partnership Self Assessment returns — its most established and widely reviewed product. This is a genuine advantage for individuals who want a single provider for both MTD quarterly updates and year-end filing.
Pay-per-submission model — no annual subscription
From approximately £2.99 + VAT per MTD submission and £14.99 + VAT per Self Assessment return, 123 e-Filing charges only when you file. For individuals who file infrequently or want to avoid recurring subscription costs, this model offers predictable, low minimum spend.
Assisted filing service for complex returns
Users can pay for a tax professional at 123 e-Filing to review or complete their Self Assessment return — particularly useful for expats, non-residents, and individuals with complex supplementary pages.
Support for all SA100 supplementary forms including foreign income
123 e-Filing supports the full range of Self Assessment supplementary pages, including those for individuals living abroad or with trust income — covering filing scenarios that go beyond standard landlord or sole trader returns.
MTD for VAT alongside ITSA from a single account
Both MTD VAT and MTD ITSA bridging can be handled within the same 123 e-Filing account. RentalBux does not currently support MTD for VAT.
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 123 e-Filing?
123 e-Filing is the better choice for:
Individuals who need Self Assessment returns filed alongside MTD
123 e-Filing's strongest use case is for people who want to file SA100 or SA800 returns and MTD quarterly updates from the same platform. For expats, non-residents, and those with complex supplementary pages, the assisted service is a further advantage.
Users who want pay-per-submission with no annual commitment
For individuals who are infrequent filers, dislike ongoing subscriptions, or want to pay only when they actually submit, 123 e-Filing's per-submission model eliminates the risk of paying for unused software.
Landlords and sole traders who need MTD VAT alongside ITSA
123 e-Filing covers both MTD VAT and MTD ITSA bridging from a single account. RentalBux does not currently support MTD for VAT.
Individuals with overseas tax filing needs
123 e-Filing supports all SA100 supplementary forms including foreign income pages, and has a user base that includes non-residents filing UK returns from abroad. The assisted service is particularly useful in this context.
Users who already have well-organised Excel records and want the simplest possible filing route
If your bookkeeping is done and you simply need to upload your figures to HMRC without committing to a new platform, 123 e-Filing provides a pay-as-you-go option — though users should be aware of the amendment charge policy before proceeding.