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Custom software for accounting firms

Custom software for accounting firms handles the work around the numbers: collecting documents from clients, tracking every return and close through its stages, a client portal for uploads, signatures and payments, and syncing with the accounting and tax tools you already use. Zoti builds this kind of software for CPA, bookkeeping and tax firms, starting at $499/month.

Updated November 3, 2026

Starts at
$499/month
Best for
Firms that chase documents by email and track work in spreadsheets
Common builds
Client portal, document requests, workflow board, billing

The problems busy season exposes

Accounting firms rarely struggle with the accounting. They struggle with the chase. From January to April, staff spend hours emailing clients for a missing 1099, a K-1 that has not arrived, or last year’s carryover figures. Documents come in as phone photos, password-protected PDFs and shoeboxes. Someone keeps a spreadsheet of which returns are waiting on the client, in preparation, in review or ready to file, and that spreadsheet is out of date by lunch.

The rest of the year has its own rhythm: monthly bookkeeping closes, quarterly estimates, payroll filings, extensions coming due in the fall, and advisory work that is hard to bill when nobody tracks it. A firm with 300 clients and five staff can run on email and memory. A firm with 1,500 clients cannot.

Software for accounting firms: what we build

  • Client portal: one secure login where clients upload documents, answer an organizer, sign engagement letters and authorization forms, and pay invoices.
  • Document collection: request lists generated from last year’s return, automatic reminders until each item arrives, and files named and filed to the right client and year.
  • Workflow board: every return, close and filing moving through your own stages, with due dates, reviewer assignment and a clear view of what is stuck.
  • Recurring work: monthly and quarterly jobs that create themselves with checklists, so bookkeeping clients never fall through the cracks.
  • Billing and engagement: proposals, engagement letters, fixed-fee or hourly billing and payment collection tied to the client record.
  • Integrations with QuickBooks Online, Xero, your tax software’s exports, payroll providers, e-signature and payment processors.
  • Capacity and profitability reports: hours per client, realization on fixed fees, and which staff are overloaded in March.

Practice management tools vs. a custom build

There are good practice management platforms made for accounting firms. Karbon, TaxDome and Canopy are well known, and each covers some mix of workflow, client portals, document requests and billing. For many firms, picking one and setting it up carefully is the right move.

Custom software makes sense when your firm does not fit their shape. Examples: a firm that mixes tax, bookkeeping and payroll for a niche such as dental practices or trucking companies and wants industry-specific organizers; a firm that sells a branded client app as part of its service; a firm that needs data from client ledgers pulled into its own dashboards; or a firm that has already stitched four tools together and wants one system. A custom portal can also sit on top of the tools you keep, rather than replacing them.

Security and record keeping

Client tax and financial data is sensitive, and firms that prepare returns have obligations to protect it, including having a written information security plan. Software for a firm should include multi-factor login, encryption, permission by staff role, audit logs of who opened which files, and retention rules for how long documents are kept and when they are deleted.

Requirements for data security, record retention and client consent come from federal rules, state boards of accountancy and professional standards, and they vary by state and by the services you offer. We build to the policies your firm sets; we do not give compliance advice.

How a project works

  1. Map your yearWe walk through busy season, extensions and recurring work, and list every stage, document and hand-off.
  2. Design the portal and boardYou click through what clients and staff will see before any code is written.
  3. Build before busy seasonWe plan rounds so the parts you need most are live and tested before January, not during it.
  4. Connect your toolsAccounting, payroll, e-signature and payments are linked, and client lists are imported.
  5. Run it and refineAfter the first season we adjust stages, reminders and reports based on what actually happened.

Practical AI for accounting firms

AI is good at reading and sorting documents: recognizing a W-2 from a 1099, pulling the figures into a checklist, flagging what is missing compared with last year, and drafting the reminder email. It is also useful for categorizing bank transactions for bookkeeping review. Staff still review everything that goes into a return or a set of books.

We also build for insurance agencies, mortgage brokers, staffing agencies and appraisers businesses in professional services.

Questions

Common questions

What is the best software for accounting firms?

It depends on what you offer and how many clients you serve. Karbon, TaxDome and Canopy suit many firms that want workflow, portals and billing in one product. If your niche, branding or integrations do not fit those tools, a custom build or a custom portal connected to your existing stack is worth comparing.

Can a custom client portal work with QuickBooks Online or Xero?

Yes. Both offer ways for other software to read and write data, so a portal can show balances, pull reports or create invoices. We confirm exactly what the connection supports during planning.

How much does custom software for an accounting firm cost?

With Zoti, custom projects start at $499/month, which covers design, development, hosting and ongoing changes. The price depends on how much you need, such as a portal only or full workflow and billing, and you get a written quote before work starts.

Can we get it built before tax season?

It depends on scope and when you start. We map the project first and agree which pieces must be ready before January, then build those first so the season is not your first test.

Will clients actually use a new portal?

They are more likely to if it is simple: one login, a clear list of what is needed, phone uploads, and reminders that stop once an item arrives. We design the client side for people who log in a few times a year.

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