Software for bookkeepers and accountants: engagement letters and retainers

A small practice loses hours in three places: the scope that grew past the retainer, the client whose bank statements show up on the 20th, and the invoice that goes out late because the close ran late. The ledger lives in QuickBooks Online or Xero and the returns in your tax software. SoloWOS handles the engagement and the billing around them.

From a fit call to a paid retainer

1. A business owner books a free 30-minute "Fit call" on your booking page. The booking form asks the entity type (sole proprietor, LLC, S corp), roughly how many transactions a month, the software they use and how many months behind they are.
2. Send a proposal with the monthly retainer as one line (for example, monthly bookkeeping up to 150 transactions, $450), catch-up work priced per month behind, and the year-end return as a separate line. Give it a 14-day expiration and a 50% deposit on the catch-up.
3. On acceptance, the engagement letter goes out for e-signature: scope, what's out of scope, the client's responsibilities, the day documents are due each month, fees and how either side ends the engagement. Two owners can sign in order, and you keep the certificate with the audit trail.
4. Create the catch-up deposit invoice from the proposal, then set the retainer invoice to repeat monthly on the 1st. SoloWOS sends each one with the card pay link (through your own Stripe account) and your ACH or Zelle details as text, with reminders 3 days before and 3 and 7 days after the due date.
5. Send an onboarding form for the basics: which bank and card accounts to reconcile (names only), payroll provider, who approves expenses. Statements and tax documents come through your secure portal or file share, because SoloWOS forms can't take uploads.
6. Each client gets a task on the month's close board, with columns such as "Waiting on client", "Reconciling", "Review" and "Sent". Send the finished statements as a PDF with Document Tracking and see when the owner opens the P&L.

A typical month

• The 1st: twelve retainer invoices go out on their own, each with the pay link.
• The 5th: the close board shows four clients in "Waiting on client". You email them; SoloWOS has no date-based document reminders.
• The 12th: a restaurant owner books a 45-minute planning session you charge for at booking, ahead of the quarterly estimated tax payment.
• The 18th: you send statements for eight clients as tracked PDFs and record a 5-minute walkthrough for the one whose margins dropped.
• The 25th: two retainer invoices are still open; the 3-day overdue reminder already went out. The time report shows one client took 6 hours on a $450 retainer, so you note a price change for renewal.

All 13 tools, one by one

A practice uses some of these every month and a few only now and then. Here's each one, honestly:

• Link in Bio: rarely needed in a referral-based practice. The case where it helps: one page with your fit-call booking, your services and a link to your secure client portal, for your LinkedIn profile.
• Short Links: a short link to your fit-call page for the chamber of commerce newsletter, or a QR code on the last slide of a small-business tax workshop, with clicks counted per link.
• Forms: the onboarding questionnaire: entity type, accounts to reconcile by name, payroll provider, who signs off. It can't take file uploads, and it's no place for Social Security or account numbers.
• Scheduling: fit calls, monthly review meetings and, in tax season, 45-minute planning sessions you can charge for at booking with a fixed deposit.
• Proposals: the retainer proposal with a monthly line, catch-up work priced per month behind and add-ons such as payroll or sales tax filings, with an expiration date and a percentage deposit.
• E-Signatures: the engagement letter and its annual renewal, with signing order for two owners and an audit trail certificate. Solo includes 15 signature requests a month, Team 50.
• Document Tracking: monthly financial statements and management reports behind a passcode, with an expiration date and an alert when the owner opens them. Keep tax returns in your tax software's portal.
• Screen Recording: a 5-minute walkthrough of the month's P&L and cash flow, so the owner hears why margins dropped without another meeting; they can comment at the exact second they have a question.
• Notes & Boards: the month-end close board, one task per client with a due date, plus a page per client with their chart-of-accounts quirks and who to ask about what.
• Time Tracking: time each client's close even on a flat retainer, so you see who takes 3 hours for a $300 fee; billable extras go on an invoice with "Add unbilled time".
• Invoicing: the monthly retainer as a recurring invoice on the 1st, with a card pay link, your ACH or Zelle details as text and automatic reminders. Nothing charges a card on file.
• Expenses: your own practice costs: software subscriptions, CPE, professional liability insurance and mileage, with receipts. It's not where client books live.
• Automations: when an engagement letter is signed, create an onboarding task and email the client your onboarding form; if a proposal sits unaccepted for 5 days, send a follow-up.

Client data and records rules that apply to you

Two federal rules shape how a tax or bookkeeping practice handles client information. SoloWOS doesn't make you compliant with either, but they decide what you should keep out of it.

• The FTC Safeguards Rule lists tax preparation firms among the financial institutions it covers and requires an information security program with administrative, technical and physical safeguards. The IRS reminds tax pros that they need a Written Information Security Plan, and IRS Publication 4557 has a checklist for building one. Firms with information on fewer than 5,000 consumers are exempt from some provisions.
• If you practice before the IRS, Circular 230 section 10.28 requires you to return a client's records promptly when they ask and need them for their federal tax obligations; you may keep copies. In a fee dispute, the IRS Office of Professional Responsibility says state law decides whether you may hold back any records.
• In practice: keep Social Security numbers, bank account numbers and tax returns in your tax software, client portal or secure file share, not in SoloWOS forms, notes or tracked links. List SoloWOS in your security plan as the vendor for scheduling, engagement letters and billing.

This is general information, not legal advice. Rules vary by state; check yours with a lawyer or your licensing board.

SoloWOS, TaxDome or Canopy: which fits

TaxDome and Canopy are practice management platforms built for accounting and tax firms. Like SoloWOS, they sit next to your ledger and tax software rather than replacing them. The real difference is the client portal side, which is what this table compares.

Choose TaxDome or Canopy if:

• Clients need to send you documents through a portal, which SoloWOS can't take.
• You run tax season with several preparers and need a workflow per return.
• You want everything that touches client tax data inside one platform built for it, which keeps your security plan simpler.

Choose SoloWOS if:

• You're a solo bookkeeper or a small practice, and the gaps are selling the retainer, signing the engagement letter and getting paid every month.
• Documents already reach you through your accounting software or a file share, and you'd rather not pay for a seat by the year.
• You also want booking pages, proposals and tracked PDFs in the same account.

Prices and features checked on October 23, 2026 on each company's site.

Start with these three

Invoicing, to set this month's retainers to repeat; E-Signatures, for the engagement letter on your next new client; and Notes & Boards, for the close. Proposals come next, once you've saved one template per service.

Free tools that help

• Retainer calculator to price a monthly retainer from the hours a client really takes.
• Billable utilization calculator to see how much of your week is billable once client chasing is counted.
• DSO calculator for how long your own practice waits to get paid.
• Self-employment tax calculator to send a new sole-proprietor client who asks what they'll owe.
• Invoice late fee calculator for the late-fee clause in your engagement letter.

What SoloWOS won't do for an accountant

• It isn't accounting software: no ledger, bank feeds, reconciliation, payroll, tax preparation or e-filing.
• Clients can't upload documents through a form or the portal.
• No document reminders on a calendar date: automations run on events (a form submitted, a proposal accepted, an invoice paid), so the monthly "send your statements" email is yours to send.
• Retainers repeat as invoices the client pays from a link; nothing charges a saved card.
• SoloWOS doesn't file taxes, issue 1099s or collect sales tax for you. Invoicing sends the invoice with a pay link (card through your Stripe account) and your other payment details; your accountant or tax software handles the rest.