Ignition: engagement letter software with automated billing and payments

Is Ignition worth using in 2026?

Ignition is built for firms that want their proposals, engagement letters, billing and payments to run as one automated flow — with payment details collected upfront, so signed work is paid work.

The platform's design premise is that the agreement and the payment belong in the same document: a client signing an Ignition proposal accepts the engagement letter terms and provides payment details in the same step, after which invoicing and payment collection happen automatically — including instant billing for out-of-scope work when the engagement changes.

Ignition reports more than 8,500 service-based businesses on the platform, with a 14-day free trial that requires no credit card.

How Ignition is positioned

Ignition describes itself as a single platform to "sell, bill and get paid" — automating deals, proposals, contracts, billing and payment collection, purpose-built for professional services. Its own FAQ draws the category line explicitly: the platform focuses on client engagement, proposals, billing and payment automation, complementing traditional accounting software and practice management systems rather than replacing them.

The current emphasis is pricing intelligence: AI-powered Price Insights, built on real proposal data, give firms tailored pricing guidance, with Ignition citing 40% more revenue for firms using the feature. Bulk agreement renewals with automatic price increases carry the same theme into the annual renewal cycle.

Why engagement letters matter now

The engagement letter is the accounting profession's first line of defense in a dispute — and the profession's own liability data shows how often it's missing. The figures below are drawn from the primary sources (the Journal of Accountancy, AICPA & CIMA, and The Tax Adviser, each reporting the CNA claims database behind the AICPA Professional Liability Insurance Program), each linked so you can verify them directly.

Ignition by the numbers

The figures below are drawn from Ignition's own site — including its published customer stories — and describe the scale and shape of the platform rather than independent benchmarks.

What is engagement letter software?

Engagement letter software creates, sends and manages the formal agreements between a firm and its clients — the documents that define the services, terms, scope and payment details of an engagement — with e-signatures, templates and renewal handling built in. It replaces the Word-document-and-PDF process where letters go unsent, unsigned, or out of date, which is exactly the gap the profession's liability data keeps finding.

Ignition implements this with the agreement connected to what follows it: engagement letter terms form part of the online proposal, templates from selected accounting industry bodies keep the language compliant, up to ten decision-makers can review and sign, and — the platform's defining step — payment details are collected in the same document, so acceptance triggers automated billing and payment collection. Bulk renewals let a firm update terms and apply price increases across its client base at renewal time.

Key factors in engagement and billing software for a firm

Firms comparing engagement letter, proposal and billing platforms commonly evaluate them across these areas:

• The agreement and the payment in one step — payment details captured at signature, so accepted work starts billed rather than invoiced later.

  Chasing payment is a process failure that begins at the proposal.

• Compliant, current letter templates — industry-standard engagement letter language, versioned and reissued every year rather than copied from last year's PDF.

  The profession's claims data shows the missing letter is the common failure.

• Scope changes that get billed — a defined path from out-of-scope request to amended agreement to invoice.

  Scope-of-service disagreements sit behind the most frequent liability claims.

• Renewals at portfolio scale — annual re-engagement and price changes handled in bulk, not client by client.

  The renewal cycle is where firm pricing decisions actually take effect.

• Invoicing synced to the ledger — invoices created and reconciled in the firm's accounting platform automatically.

  A billing layer that doesn't write to the ledger creates its own reconciliation job.

• Fit with the practice stack — connections to the practice management and workflow tools the firm already runs.

  Engagement software sits in front of the practice system, never instead of it.

Ignition's published feature set covers all six areas: payment details collected upfront in proposals, legally vetted and industry-body engagement letter templates, scope-change adjustment with instant billing for additional work, bulk renewals with automatic price increases, invoices created and marked paid in Xero or QuickBooks Online, and integrations spanning practice management tools including Karbon, TaxDome and Xero Practice Manager.

Ignition at a glance

Key features: from prospect to paid

Ignition's defining capability is that one signed document carries the sale, the legal agreement and the payment authority — everything after it is automation.

1. Proposals with AI Price Insights

Selling — branded online proposals are built from templates and a services library, presented with pricing options, and signed online. AI-powered Price Insights, built on real proposal data, guide what to charge; Ignition cites 40% more revenue for firms using the feature.

The pricing decision gets data before the proposal goes out.

2. Engagement letters built into the proposal

Agreements — engagement letter terms form part of the proposal itself, drawn from legally vetted templates and templates from selected accounting industry bodies, with e-signature for up to ten decision-makers. Terms libraries keep language consistent across the firm.

The letter can't go unsent — it's the document the client signs.

3. Payments collected upfront

Money — client payment details are collected in the proposal; once signed, billing and payment happen automatically, and invoices are created and marked paid in the firm's ledger. Ignition frames the outcome as eliminating accounts receivable.

Acceptance and payment authority arrive in the same signature.

4. Scope changes billed instantly

Scope — when the engagement changes, the agreement adjusts and additional work is billed instantly, with dedicated scope-creep management in the platform. Out-of-scope work moves from awkward conversation to line item.

The change request and its invoice are the same action.

5. Bulk renewals and price increases

Renewals — client agreements renew in bulk, with updated terms and automatic price increases applied across the portfolio at renewal time.

Annual repricing becomes one operation, not hundreds of letters.

6. Deals, forms, AML and reporting

Pipeline to insight — Deals manages the pipeline from lead to signed client, Forms automate data collection from lead capture to client intake, AML compliance tooling supports regulatory checks, and the reporting dashboard shows projected revenue and billing at a glance.

The platform covers the commercial layer end to end — prospect to paid to projected.

What is proposal software for accountants?

Proposal software for accountants produces the priced, branded, e-signable offer a firm sends a prospective client — services, options, terms and acceptance in one online document — replacing the emailed PDF and its follow-up thread. For accounting firms specifically, the proposal carries an extra load: it doubles as the engagement letter that professional standards and liability insurers expect on every engagement.

Ignition merges the two by design: the proposal contains the engagement letter terms and the payment details, so a single client signature closes the sale, executes the agreement and authorizes the billing. Templates cover the proposal side (a published template library) and the agreement side (industry-body letter templates), with acceptance tracking showing opens, views and signatures in real time.

In an accounting firm, the proposal and the engagement letter are the same document — Ignition treats them that way.

What is billing software for accounting firms?

Billing software for accounting firms automates the invoicing and payment collection for client engagements — recurring fees, fixed fees and out-of-scope additions — and reconciles the results into the firm's ledger. It differs from generic invoicing software for accountants' small-business clients in that the billing follows the firm's own engagements: what was agreed, at what price, on what schedule, and what changed along the way.

In Ignition, billing runs from the signed agreement: invoices are generated on the agreed schedule, payments collect automatically from the details captured at signature, scope changes bill instantly, and everything is created and marked paid in Xero or QuickBooks Online. The reporting dashboard shows projected revenue and billing across the client base.

The agreement is the billing instruction — the firm doesn't issue invoices, the platform does.

How Ignition runs a client from prospect to paid

Ignition models the commercial side of an engagement as one connected flow:

• Capture: Forms take the lead's details and intake information; Deals tracks the prospect through the pipeline.
• Propose: a branded proposal goes out from templates, priced with AI Price Insights, with the engagement letter terms built in.
• Sign: up to ten decision-makers review and sign online, providing payment details in the same step.
• Bill: invoicing and payment collection run automatically on the agreed schedule, created and marked paid in the ledger; scope changes bill instantly.
• Renew: at the end of the term, agreements renew in bulk with updated terms and automatic price increases, and the dashboard shows projected revenue ahead.

Connected practice tools — Karbon, TaxDome, Xero Practice Manager and others — pick up the delivery side, with Ignition supplying the signed engagement and the money flow around it.

Pricing model

Ignition publishes its plans in USD at ignitionapp.com/pricing, noting current plans and pricing have been effective from December 2024 for new customers, with a 14-day free trial that requires no credit card. Pricing changes over time, so verify current plans directly on ignitionapp.com/pricing.

The comparison Ignition itself frames is commercial: the platform against the revenue leakage it targets — unsigned letters, unbilled scope changes, late payments and under-priced renewals — with its customer stories stated in those terms.

What the platform includes

• Proposals, engagement letters, billing and payment collection in one platform, with one client signature driving all of it
• Legally vetted and industry-body engagement letter templates, e-signable by up to ten decision-makers
• Automated invoicing synced to Xero or QuickBooks Online, instant billing for out-of-scope work, and bulk renewals with automatic price increases
• AI-powered Price Insights, Deals pipeline, Forms, AML compliance tooling and a revenue-projection dashboard

Considerations before adopting

• Ignition positions itself as complementing practice management and accounting software — firms wanting workflow, document or job management need those systems alongside it
• The automation model assumes clients sign online and pay by stored details; firms should map which clients and payment methods that covers (Ignition notes payment support varies by country)
• Moving a client base onto upfront payment terms is a commercial change as much as a software one — the renewal cycle is the natural migration point

Who Ignition is built for

• Accounting and tax firms and bookkeepers — the segments Ignition publishes dedicated solutions for, alongside agencies, consultants and financial advisors
• Firms running recurring, agreement-based client relationships where billing should follow the signed engagement automatically
• Practices from solo through mid-market and enterprise, per Ignition's published solution tiers

What it is not designed as

• A practice management or workflow system — Ignition's own FAQ positions it as complementing those platforms, and it integrates with them instead
• A ledger — invoices are created and reconciled in Xero or QuickBooks Online, not in a general ledger of its own