The client portal and practice workspace for tax firms
Requests, documents, assignments, and reviewer sign-off live on one record for each engagement. Zacello works alongside the tax software your firm already uses. Built by Syntonyl and onboarding pilot firms now.
Most practices run tax season across email threads, shared drives, and a spreadsheet someone keeps meaning to update. Files arrive without anyone confirming they answer the request, the final document is called W2_final_v3_REAL.pdf, and review notes live on sticky notes. Every handoff means reconstructing the same story.
Zacello is the client portal and practice workspace our team at Syntonyl built around those handoffs. Each engagement connects a client and tax year with an assigned preparer and reviewer, intake answers, document requests, tasks, and an internal review history. Clients work through their requests in a portal, and staff see what has arrived, what has been accepted, and who is responsible next.
Documents are tracked from upload to accepted evidence. Each upload is saved as its own version, scanned for malware, and held until staff accept that exact version, waive the request, or ask for a correction. During preparation, values are captured against the source page, so the reviewer can see where each number came from. Text recognition can suggest values, but staff confirm every one.
Zacello does not replace your tax software. Keep using it to prepare and e-file returns. Zacello handles the work around the return: intake, documents, assignments, review, and client delivery. We are running a pilot with a small group of tax practices. Read the founder's write-up for more background.
What Zacello does
Engagements with clear ownership
Client, tax year, return type, preparer, and reviewer are set when the engagement opens, so everyone knows whose work it is.
Client portal requests
Clients get an organizer and a checklist of documents to upload, plus secure messages, in their own portal instead of email attachments.
Versioned, scanned uploads
Every upload is saved as a version that cannot be edited, checked for malware before staff can open it, and accepted, waived, or returned for correction.
Source-linked preparation
Supported workpapers capture values against the source document and page. Readiness checks run before work goes to review.
Explore Zacello
Zacello features
What Zacello does: engagements with clear ownership, client portal requests, versioned, scanned uploads, source-linked preparation, and more.
Read more →Use casesZacello use cases
How teams use Zacello: chasing documents for a 1040; review with the evidence attached; separating ops staff from tax data.
Read more →Security & accessZacello security & access
Tax data needs strict access. In Zacello, access is checked on every request against the person's current role and assignments, and clients only ever see…
Read more →Pilot programZacello pilot program
Zacello is in a pilot with a small group of tax practices. Pilot firms get the full workspace, help setting it up, and a direct line to the team building…
Read more →FAQZacello FAQ
Answers to common questions about Zacello: does zacello replace our tax software; does zacello calculate tax.
Read more →Related
IVOKER
IVOKER is a private AI operator from Syntonyl. It remembers how your business works and handles mail, files, research, and computer tasks, with your approval.
Read more →SECCybersecurity & Resilience
Practical protection for applications, identities, devices, and networks, including assessments, hardening, access controls, monitoring, and recovery planning.
Read more →OPSManaged Technical Operations
Ongoing hosting, monitoring, maintenance, support, and improvement for the systems your business runs on, with clear responsibility for each one.
Read more →GlossaryEngagement letter
A signed agreement that defines the services a firm will provide, the responsibilities of each party, fees, and the limits of the engagement.
Read more →GlossaryTax organizer
A questionnaire and document checklist a firm sends clients each season to gather the information needed to prepare their return.
Read more →GlossaryWorkpapers
The documents, calculations, and notes that support the figures in a return or financial statement and record how the preparer reached them.
Read more →GlossaryPreparer–reviewer separation
The practice of having someone other than the preparer review and approve work before it is released, with a record of what was reviewed.
Read more →GlossaryWritten Information Security Plan (WISP)
A written plan describing how a business protects customer information, required for tax professionals under the FTC Safeguards Rule.
Read more →GlossaryClient portal
A secure, signed-in website where clients exchange documents, answer requests, sign agreements, and receive results.
Read more →GlossarySection 7216 consent
Taxpayer consent required before a tax return preparer uses or discloses tax return information for purposes outside preparing the return.
Read more →Want to see Zacello on your own work?
Tell us what you would bring to Zacello. We’ll arrange a walkthrough and talk through fit, access, and onboarding.