Comparison · facts checked
OnDue vs Monk
Both use AI to chase invoices. Monk is a wide platform sold through demos, built for finance teams with an ERP, with more channels and modules. OnDue is newer and narrower: owner-approved email reminders for teams on QuickBooks Online or Xero, with its prices published.
What Monk does better
- QuickBooks and Xero plus 14 other accounting and ERP systems on its integrations page, from NetSuite and SAP S/4HANA to Workday and Oracle.
- An AI voice agent that makes outbound calls, answers inbound calls and callbacks, and leaves voicemails.
- AP portal submission: it registers as your vendor in 600+ buyer portals like Coupa and SAP Ariba, and handles rejections and resubmission.
- Cash application, deductions, a 13-week cash forecast (beta) and customer credit risk in the same product.
- Independent security attestations, SSO and role-based access today.
Which one to pick
Pick Monk if
- You run NetSuite, SAP, Oracle, Workday, Dynamics or another ERP.
- Many of your customers make you submit invoices through AP portals.
- You want AI phone calls as part of collections.
- You need cash application, deductions or forecasting now.
- Your procurement checklist needs security attestations or SSO today.
- You want customers paying in a portal, or reminders sent without approval, today.
Pick OnDue if
- Your books are in QuickBooks Online or Xero.
- You want to see the price before you talk to anyone.
- You would rather connect your books yourself than book a demo.
- You want a person to approve every AI-drafted reminder before it goes.
- Email reminders and sorted replies cover the job for now.
Line by line
Monk facts are from Monk’s own pages and the sources listed below, read on November 8, 2026. Products change; check before you buy.
Pricing
Not published. The homepage says “Pricing scales with business volume. Book a demo to learn more.” Monk’s blog describes a flat monthly fee, not a percentage of collections.
Source: monk.com/blog/best-ar-automation-for-small-businessPublished early-access prices: Starter $49/mo, Growth $149/mo, Scale from $499/mo; annual billing gets 2 months free. Billing hasn’t started, so nobody is charged during early access.
How you buy
Request early access; accounts open in small batches. Then you connect your books yourself, with no implementation project.
Time to go live
“3 weeks” average go-live on the homepage. Its methodology page says teams go live “in under a month”.
Source: monk.com/methodologyConnect QuickBooks Online or Xero by signing in; open invoices import straight away. We haven’t measured go-live times across customers, so we don’t publish one.
Accounting systems
QuickBooks and Xero plus 14 other accounting and ERP systems listed, including NetSuite, SAP S/4HANA, Oracle, Workday, Dynamics 365 and Sage Intacct. Monk says dedicated internal resources own each integration.
Source: monk.com/platform/integrationsQuickBooks Online and Xero. NetSuite, Sage Intacct, Business Central, Acumatica, Odoo, Oracle Fusion Cloud ERP and Deltek Vantagepoint Coming soon
Email collections
Drafts each follow-up from the account’s context (invoice, history and thread), and re-routes when a message bounces. Playbooks set tone, cadence and escalation rules per account tier.
Source: monk.com/platform/intelligent-collectionsAI drafts each reminder from the invoice and its step in the cadence. Early-access accounts run the standard cadence (days 1, 7, 14 and 30 after due); custom cadences Coming soon
Replies and disputes
A promise to pay pauses follow-up until the promised date. A dispute opens with the invoice, the reason and an owner, and only the contested invoice pauses.
Source: monk.com/platform/disputesReplies sorted into promise to pay (held to the promised date), dispute or question, already paid, wrong contact and out of office. A dispute pauses that invoice only and comes to you.
Human control
Review every draft before it sends, or turn on auto-send. Anything uncertain is drafted for review instead of sent.
Source: monk.com/platform/intelligent-collectionsEvery reminder waits for your approval: approve, skip or approve the batch. Editing drafts and sending without approval Coming soon
Voice calls
An AI voice agent makes outbound calls and handles inbound calls and callbacks. Voice support entered beta on July 15, 2026; voicemail templates were added October 31, 2026.
Source: monk.com/changelogNo phone calls.
SMS and WhatsApp
WhatsApp is listed as a native channel. SMS isn’t mentioned on the page we read.
Source: monk.com/platform/intelligent-collectionsEmail today. SMS and WhatsApp Coming soon, once client-consent capture is in place.
AP portal submission
Says it supports 600+ corporate payables portals, including SAP Ariba, Coupa, Bill.com, Tipalti, Tungsten and Workday.
Source: monk.com/platform/portalsNot available. Coming soon
Customer payments
A portal where customers see open invoices, statements, credit memos and payment history, and pay invoices. The page doesn’t list payment methods or fees.
Source: monk.com/platform/payment-hubA card and ACH pay page through Stripe, at Stripe's standard rates with no OnDue fee, Coming soon. Today customers pay the way they already do, and OnDue stops the reminders when you record the payment.
Cash application
Matches incoming payments and posts them to the connected ERP. Monk says 80% match automatically, rising to 95% with suggested rules (its own figures).
Source: monk.com/platform/cash-applicationPayments you record in your books stop the reminders. Bank-feed cash application Coming soon
Deductions, credit, forecasting
Automatic deduction and short-pay classification, credit risk on the customer page, a Payment Risk report (beta) and a 13-week cash forecast (beta since June 15, 2026).
Source: monk.com/changelogNot available. A 13-week cash forecast is Coming soon
Security attestations
Its security page lists an independent security attestation report, ISO 27001, GDPR and CCPA badges, and offers reports through its trust center.
Source: monk.com/platform/securityNone yet. OnDue holds no third-party certification or attestation. Ask us for our security questionnaire answers.
SSO and roles
SSO, MFA and role-based access are listed on its security page.
Source: monk.com/platform/securityOptional authenticator-app two-factor sign-in and owner and member roles today. SSO and finer roles Coming soon
Published results
Says teams see DSO drop by more than 40% and save about 26 hours a month, “measured with our first 100 customers”, and that it resolves 87% of collections with no human intervention (engineering data, July 2026). The methodology page gives no time window for these figures.
Source: monk.com/methodologyNone yet. OnDue is new. We won’t publish results until we can show how they were measured.
If you’re evaluating both
Ask each vendor the same five questions, and get the answers in writing.
- What will I pay in year one, all in? Platform fee, implementation, seats, and any fee on payments.
- When does the first reminder reach a real customer? Ask for a date, not an average.
- Can I approve every message before it goes? For how long, and what changes if I stop?
- What do you write to my books? Which records change in QuickBooks or Xero, and which are never touched?
- How were your published results measured? Sample size, time window, and how customers were chosen.
Questions
How much does Monk cost?
As of November 8, 2026, Monk does not publish pricing. Its homepage says pricing scales with business volume and asks you to book a demo, and its blog says it charges a flat monthly fee rather than a percentage of collections. We don’t know its prices, so ask for a written quote. OnDue’s early-access prices are public: $49, $149 and from $499 a month, and nobody is billed during early access.
Is OnDue a Monk alternative for QuickBooks Online and Xero?
For some teams. OnDue is built for businesses whose books are in QuickBooks Online or Xero and who want owner-approved AI reminders without a sales process. It is in early access and does less than Monk: no calls, no portals, no pay page yet. If you run NetSuite, SAP, Oracle or another ERP, Monk supports far more systems today.
Does OnDue make phone calls like Monk?
No. OnDue sends email and sorts the replies. If phone outreach is central to how you collect, Monk is the stronger choice today.
Can OnDue submit invoices to Coupa or SAP Ariba?
Not today. AP portal submission is on the OnDue roadmap. Monk lists more than 600 portals, which matters if many of your customers require them.
Why does this page say where Monk is ahead?
Because a comparison that only lists your own strengths is an ad. Monk has more integrations, more channels and more modules. OnDue is narrower, publishes its prices and lets you connect your books yourself. Pick the one that fits.
Sources, read November 8, 2026
- Monk homepage
- Monk: Intelligent Collections
- Monk: Disputes
- Monk: AP Portals
- Monk: Cash Application
- Monk: Payment Hub
- Monk: Integrations
- Monk: Security
- Monk: Methodology (last updated November 2, 2026)
- Monk: Changelog
- Monk blog: best AR automation for small business (updated July 9, 2026)
We don’t use Monk’s logos, screenshots or copy. Spot something out of date? Email hello@ondue.ai and we’ll fix it.
Other comparisons: Upflow · Chaser · Paidnice · Tesorio · Versapay
Next time an invoice goes late, let OnDue draft the first email.