Best Invoicing and Billing Platforms with Client Portals and Online Pay

An electronic bill presentment platform for utilities and governments with 160+ pre-built ERP integrations.

Editor's takeInvoiceCloud processes 133 million transactions a year across more than 3,200 local governments, with over 160 pre-built real-time integrations into systems like Oracle Utilities and Tyler Technologies CIS platforms. Guest checkout lets payers pay without creating an account, and one resolution cited a 50 percent increase in paperless enrollment within a year of conversion. The friction points sit with end-users, since convenience fees around $2.95 per credit card payment are common, and the Better Business Bureau lists complaints about difficulty reaching customer support, alongside reports of login loops and session timeouts.

Budget accounting software for small businesses outside the US, starting at $10 a month.

Editor's takeSage Business Cloud Accounting undercuts many rivals at $10 a month for its Start plan and $25 for full Accounting. That value no longer applies to US buyers. Sage officially retired the product in the United States as of December 31, 2024, with support ending January 31, 2025, so this listing now applies mainly to international small businesses.

All-in-one CRM, billing and client portal platform with unlimited users and extreme white-labeling.

Editor's takeAdding staff or clients never raises the bill, even on the $19 Start plan. It bundles CRM, an LMS and billing with white-labeling deep enough to hide the SuiteDash name entirely. The tradeoff shows up in the interface, which reviewers call outdated and difficult to learn at first.

ISO 27001 certified practice management platform with Stripe payments and US insurance claiming for allied health.

Editor's takeZanda Health, formerly Power Diary, holds ISO 27001 certification, a rare standard among practice management platforms in this niche. It integrates directly with Stripe for payments and keeps protected health information separate from billing data. US insurance claiming adds a $50 enrollment fee plus $0.15 per claim, and SMS reminders carry extra per-message costs.

An API-first global payments platform with 160+ local payment methods, multi-currency accounts and like-for-like settlement.

Editor's takeAirwallex's like-for-like settlement, holding funds in the currency customers actually paid in across 130-plus currencies, is a genuine edge for businesses tired of forced conversions. The account-freeze complaints are the real risk to weigh: several businesses describe funds locked for weeks during compliance reviews with slow, unclear communication from support.

AI-powered AP/AR platform with two-way sync to QuickBooks, Xero, and NetSuite.

Editor's takeBILL automates AP and AR with OCR invoice capture and two-way accounting sync, a real time-saver for finance teams. Its 7.1 million member payment network and public-company backing signal stability. Reddit and review sites carry repeated reports of frozen funds and slow support, a real cost when cash flow is on the line.

A law firm client portal for secure invoicing, payments, and document sharing with IOLTA compliance built in.

Editor's takeBill4Time builds IOLTA and ABA trust-accounting compliance directly into its client portal, letting clients pay via LawPay, Stripe, or PayPal while staying within bar association rules. Data lives in SSAE-18 Type II certified centers with 256-bit SSL encryption and supports MFA. The QuickBooks integration only flows one direction, from Bill4Time to QuickBooks, exporting totals rather than line-item detail, and per-user pricing runs from $27 to $80 a month depending on tier.

A proposal-to-payment platform for professional services that collects payment details upfront.

Editor's takeIgnition collects binding payment authorization inside the proposal itself, so professional service firms stop chasing unpaid invoices after the fact. Customers have processed over $13 billion in revenue through the platform, and it holds SOC 2 Type 2 certification with PCI-DSS Level 1 payment processing via Recurly. The Core plan starts at $99 a month, but a 0.3% surcharge applies to bank payments over $3,000, and support runs through an in-app messenger with a roughly 3-hour response time rather than live chat.

Free, unlimited invoicing tied to the Square ecosystem, charging only processing fees per payment.

Editor's takeSquare removes the monthly fee barrier entirely on invoicing, charging only when a payment lands, and takes the PCI compliance burden off merchants as the merchant of record. That model pairs well with businesses already on Square POS. The risk to watch is fund holds, with some users reporting a 90-day freeze on payouts.

Legal billing software with rare bi-directional QuickBooks Desktop sync and trust accounting tools.

Editor's takeTimeSolv wins on a feature most rivals dropped, real two-way QuickBooks Desktop sync. It has processed over $5.3 billion in billings since 1999, per its own G2 profile. PCMag calls its interface one of the worst in the category, a real tradeoff for that depth.

Cloud invoicing for freelancers with recurring billing, multi-currency support, and a free 5-invoice tier.

Editor's takeInvoicely keeps things simple and cheap, a Basic plan at $9.99 a month with a 5-invoice free tier. That affordability comes with a real security scar though, an October 2025 breach exposed 178,519 files. Exposed data included scanned checks, tax documents, and banking information, per a WebsitePlanet report.