Engagement letters signed where the engagement lives: in your platform.
Embedded signing for engagement letters, e-file authorizations, and client onboarding. Built for accounting-tech and practice-management platforms, with KBA where filings demand identity assurance.
Domain or work email: either way you get a branded account. No credit card, no sales call.
Just need an API key? Create a plain account
The four signing workflows every accounting platform carries
Engagement letters and renewals
Send, sign, and file engagement letters inside your platform, with annual renewals routed automatically to the right signers.
E-file authorizations and tax forms
Collect signatures on e-file authorization forms and tax documents without pulling clients out of the portal they already trust.
Client onboarding and organizers
Kick off every engagement with pre-filled onboarding packets and organizers that come back signed, complete, and filed.
Identity verification for remote signing
Layer KBA onto high-stakes filings: signers answer identity questions before the document opens, and the audit trail records it.
From engagement letter to filed packet, inside your product
Your user starts an engagement letter or filing packet from the client record in your platform.
Client and engagement data flow into the fields. Nothing is retyped.
The client signs in your portal, under your brand, on any device.
KBA confirms identity where the filing requires it, recorded in the trail.
The signed packet, certificate, and audit trail land in the engagement file.
Every firm on your platform, under its own brand
White-label works at the multi-tenant level: each firm gets its own logo, colors, domain, and email sender on every engagement letter and filing packet it sends. Firms buy envelopes through your admin center, on your paper.
Every tenant, their own brand
White-label works at the multi-tenant level. Each of your customers gets a branded experience: their logo, their colors, their domain, their emails. Not yours, and never ours.
Own the SKU
Package, price, and sell signing as part of your product. Usage-based platform pricing leaves the margin, and the customer relationship, with you.
Aligned by design
We sell through you, not around you. Your success selling downstream is the business model, so partner support is the product, not a program.
Engagement letters, organizers, e-file packets: one API shape.
Web components, not iframes: override any control, style with standard CSS. MIT-licensed SDKs on GitHub and npm. Live in 1-2 business days.
// 1. Create an envelope from your template
const envelope = await verdocs.envelopes.create({
template_id: 'engagement-letter',
recipients: [{ role: 'signer', email: client.email }],
fields: { client_name: client.name }, // pre-filled, still editable
})
// 2. Render signing inside your app
<VerdocsSign envelopeId={envelope.id} theme={yourBrand} />
// 3. Know the moment it completes
app.post('/webhooks/verdocs', ({ body }) => {
if (body.event === 'envelope.completed') fulfill(body.envelope_id)
})Common questions from accounting platforms
Can clients sign engagement letters without creating accounts?
Yes. Clients sign without accounts, authenticated to the level the document requires: from an emailed link up to MFA and knowledge-based authentication for filings that demand identity assurance.
Does Verdocs support KBA for remote tax signing?
Yes. Knowledge-based authentication is a per-use add-on: signers answer identity questions drawn from public records before the document opens, and the verification is recorded in the tamper-evident audit trail.
Can every firm on our platform have its own branding?
Yes. White-label operates at the multi-tenant level: each firm gets its own logo, colors, domain, and email sender on every engagement letter and filing packet it sends.
More questions? The full FAQ lives in the developer docs, from API auth and webhooks to eIDAS signature levels.
Going deeper on accounting
KBA for Form 8879: Designing Identity Checks Clients Finish
IRS Publication 1345 sets the identity rules for signing Form 8879 remotely. Whether clients finish depends on how tax software prepares them, enforces the failure path, and handles joint returns.
Read the post2026-08-22Product Requirements for Remote Signing of IRS Forms 8878 and 8879
IRS Publication 1345 contains a build spec for remote signing of Forms 8878 and 8879. Its nine software developer requirements, restated for product teams.
Read the post2026-08-24Who Is Responsible for Compliance When eSignature Is Embedded in Tax Software?
The IRS assigns e-file duties to roles, not contracts. Which roles your platform holds depends on what it does, and white-label resale is now one.
Read the post2025-12-14Embedding eSignature in Accounting Practice Software
What signing must handle inside practice management software: season volume, per-firm branding, and identity assurance that varies by document.
Read the postEvidence your reviewers will respect.
SOC 2 Type I · HIPAA compliant · ESIGN & UETA · eIDAS SES / AES · GDPR. Legally valid in 50+ countries and 60+ jurisdictions. Tamper-evident PDFs with digitally signed certificates and full audit trails.