We build the softwareUK accountancy runs on
Capstone Software is a UK software development company building products for the accountancy industry. Our flagship platform AccountFlow brings client management, every HMRC deadline, automated emails, time tracking, and billing into one intelligent system — engineered like modern software should be, designed with practising-accountant insight.
No credit card · Full access · Cancel anytime · Your data, always yours
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One platform, every role in the practice
Whether your client is a sole practitioner or a multi-partner firm, our software gives every team member exactly what they need.
Clients, deadlines, team workload, billable hours, and revenue in one dashboard. Stop guessing. Start managing with real data.
Every VAT return, CIS filing, confirmation statement, and Companies House deadline tracked and alerted. Overdue? You'll know instantly.
Capstone Timer is built into every plan. Running timers, weekly reports by client and user, and a native desktop app for Mac and Windows.
Bank statement requests, VAT reminders, year-end packs, MTD ITSA notices — sent automatically at the right time. Set once, runs forever.
Four products. One ecosystem.
AccountFlow is the practice hub. Capstone Timer is built in and available standalone. Capstone Engage and Guardian AML connect seamlessly when you need them.
The intelligent hub of the practice. Every client, every deadline, every automated email, and the whole team — with a compliance audit trail that satisfies GDPR and regulatory requirements.
- Unlimited clients — Ltd Companies, Sole Traders, Partnerships, LLPs, CIS Contractors
- VAT, Annual Accounts, Payroll, CIS, P11D, Confirmation Statements, MTD ITSA
- Automated email templates — bank statements, VAT docs, year end, MTD ITSA, payroll
- Practice-wide calendar view of every client submission
- Role-based team access — Admin, Manager, Staff
- Reports & analytics — compliance score, team performance, deadline pipeline
- Capstone Timer built in on every plan
- Invoicing, Stripe billing, 7-year audit trail
- Live Companies House integration — auto-import company details & deadlines
Every billable minute tracked, every client accounted for. Start timing right now from inside AccountFlow, or run the standalone desktop app alongside any application.
- Built into AccountFlow — included on every plan today
- Standalone desktop app — Mac & Windows
- One-click Start/Stop with billable toggle
- Tag entries by client and description
- Add manual time entries retrospectively
- Time-by-client and time-by-user analytics with charts
- Export-ready reports for invoicing
- Syncs across all devices and team members
Professional proposals in minutes. Pre-built accountancy service packages, tiered pricing options, online acceptance, and engagement letter generation — synced with AccountFlow client records.
- Pre-built accountancy service templates
- Branded proposals with the practice identity
- Tiered pricing — show clients their options clearly
- Online acceptance with e-signature workflow
- Engagement letter generation from accepted proposals
- Track when clients view and accept
- Synced with AccountFlow client records
Professional proposals for accountancy practices. Register for early access and a full 14-day free trial.
AML compliance without the chaos. Designed with practising-accountant insight, Guardian AML maps to how practices actually operate — satisfying ICAEW, ACCA, and AAT requirements without the spreadsheet mountain.
- Client risk assessment workflows built for accountants
- Due diligence checklists — individuals & corporates
- Suspicious activity reporting (SAR) log
- AML policy management and version control
- Staff training record tracking
- Audit-ready reports for ICAEW, ACCA, AAT reviews
- Integrates with AccountFlow client data
Final development underway. Register now for early access and an extended free trial on launch day.
A software company with accountancy DNA
We engineer like a modern software house and design with practising-accountant insight — so the workflows are right the first time.
MTD ITSA, CIS, self assessment, and limited company workflows are first-class features designed with practising-accountant insight — not afterthoughts.
VAT, Annual Accounts, Confirmation Statements, Payroll, P11D, CIS, and MTD ITSA — all tracked with overdue alerts and automated reminders.
Capstone Timer is built in on every plan — no add-ons, no extras. Know where the hours go and bill accordingly, from the free tier up.
Pre-written templates for every document request and deadline reminder — sent automatically at the right time, with the practice's branding.
Role-based access, client-user assignments, secure staff onboarding, and a 7-year audit trail for every action across the practice.
Compliance score, deadline pipeline, team workload, billable hours by client and user. Built for how practices are actually managed.
Ltd Companies, Sole Traders, Partnerships, LLPs, and CIS Contractors — each with the right fields, deadlines, and compliance workflows.
7-year audit log, practice data isolation, bcrypt password hashing, JWT authentication, CSP headers, TLS 1.2+ in transit.
Stripe-powered subscriptions, invoice tracking, and a customer billing portal. No contracts. Upgrade or cancel any time.
Client data deserves bank-grade protection
Security built at the architecture level — not bolted on after the fact.
- Cloud-hosted on Render with enterprise infrastructure
- PostgreSQL database with automated daily backups
- Redis caching with encrypted connections
- All data encrypted in transit via TLS 1.2+
- External backup storage, full restore capability
- JWT authentication with token versioning
- Password hashing with bcrypt
- Role-based permissions — staff see only what they should
- Multi-tenant architecture — complete practice data isolation
- Auto-logout on inactivity
- Rate limiting on all API endpoints
- Helmet.js — CSP, HSTS, X-Frame-Options
- Parameterised SQL — zero injection risk
- XSS protection via CSP and DOM-safe rendering
- Secure cookie settings, HTTPS-only flags
- GDPR-ready data handling and retention
- 7-year audit log for regulatory compliance
- HMRC-friendly deadline tracking and reporting
- Complete practice data isolation
- Health monitoring with UptimeRobot
- Automatic failover and disaster recovery
- Daily backups to external storage
- WAF-hardened production environment
- Every change logged: user, timestamp, action
- 7-year retention meets ICAEW & ACCA requirements
- Immutable records — cannot be edited or deleted
- Export-ready for regulatory review
Connecting with the tools practices already use
Stripe, Microsoft 365, SendGrid, and Companies House are live now. Xero and QuickBooks coming very soon.
Choose a plan. Start free.
All prices +VAT. Every plan includes time tracking and a 14-day free trial. No card required.
- All deadline types (VAT, CIS, MTD ITSA)
- Time tracking included
- Basic reports
- Client management
- Email support
- Automated emails
- All deadline types
- Time tracking included
- Basic reports
- Automated emails
- Advanced reports
- API access
- Everything in Independent
- 3 team members
- Invoicing & billing
- All integrations
- Everything in Practice
- Advanced reports
- API access
- Priority support
- Everything in Growth
- White-label branding
- Priority support
- Everything in Scale
- Custom integrations
- Dedicated account manager
- SLA support
No setup fees · No cancellation fees · Upgrade or downgrade anytime
All prices +VAT. Yearly plans save 2 months. Every plan includes time tracking and a 14-day free trial.
Genuinely competitive pricing. The Practice plan at £39/mo +VAT includes live Companies House integration and built-in time tracking — features competitors charge significantly more for, or simply don't offer. No per-user surprises on lower tiers either.
What's included in each plan
| Feature | Free | Independent | Practice | Growth | Scale | Enterprise |
|---|---|---|---|---|---|---|
| All deadline types (VAT, CIS, P11D, MTD ITSA) | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Time tracking (Capstone Timer) | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Client management | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Basic reports | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Email support | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Automated emails | – | ✓ | ✓ | ✓ | ✓ | ✓ |
| Advanced reports | – | – | – | ✓ | ✓ | ✓ |
| API access | – | – | – | ✓ | ✓ | ✓ |
| Priority support | – | – | – | ✓ | ✓ | ✓ |
| White-label branding | – | – | – | – | ✓ | ✓ |
| Custom integrations | – | – | – | – | – | ✓ |
| Dedicated account manager | – | – | – | – | – | ✓ |
| SLA support | – | – | – | – | – | ✓ |
Common questions answered
Yes. Every feature — from HMRC deadline types to VAT quarter calculations to Companies House filing dates — is built specifically for UK compliance. If you're a UK accountant, everything works the way you expect.
Yes — Capstone Timer is built into AccountFlow on every plan including Free. Start timing against any client from day one. The standalone desktop app for Mac and Windows is also available.
Yes. Import clients via CSV, or use the live Companies House integration to auto-populate company details and filing deadlines directly from the register in seconds.
Three choices: continue by adding payment details, downgrade to Free and keep up to 10 clients, or export your data and leave — it belongs to you.
We'll notify you when approaching your limit. Upgrade instantly — we prorate the difference so you only pay for what you've used.
Yes. Automated daily backups with full restore capability. All data encrypted in transit via TLS 1.2+ and stored in our PostgreSQL database with external backup storage.
Absolutely. No contracts, no cancellation fees. Export your data before you leave — it belongs to you. We'd rather earn your business every month.
Yes. CIS contractors are a fully supported entity type with monthly CIS return tracking, timezone-safe due dates, and dedicated contractor fields — built for practices with CIS clients.
Ready to stop missing deadlines?
Join UK accountancy practices using AccountFlow to stay compliant, save time, and grow revenue. Start a 14-day free trial — no card required, full access from day one.
Free plan available · Paid plans from £19.50/mo +VAT · No card required · Cancel anytime