BILL vs Stampli vs Melio: Which AP Tool Fits Your Firm?

BILL, Stampli, and Melio all pay a vendor bill by ACH, card, or check and post the result back to the ledger. Past that shared job, they are built for three different clients and priced three different ways. BILL charges per user, from $49 to $89 a month, and leans on the deepest accountant partner program of the three. Stampli publishes no price at all; it quotes by bill volume once you get on a call, and year-one spend for a mid-market client typically lands between $8,000 and $25,000. Melio starts at zero, adds a $10-per-user fee on the Core and Boost tiers, and drops per-user fees entirely only at the $80 Unlimited plan, but connects only to QuickBooks and Xero.

That spread means the right pick depends less on a feature checklist than on which client you are buying for. This guide works from a three-question filter, the client's ledger, how complex the approval chain needs to be, and what the per-client budget actually is, rather than a side-by-side score that treats a solo bookkeeper's five-bill-a-month client the same as a mid-market NetSuite account. All three sit in CurateSuite's broader AP automation comparison, which covers eleven tools across five pricing models; this piece narrows to the three a firm most often ends up choosing between.

The short answer

• Solo bookkeepers and micro clients on QuickBooks or Xero: Melio's free Go tier covers one user and five ACH payments a month at no cost, with Core at $25 a month adding approval workflows and 1099 automation.
• Multi-client firms on QuickBooks, Xero, NetSuite, or Sage Intacct: BILL has the widest accountant program and wholesale client pricing, from $49 to $89 per user per month.
• Mid-market clients on NetSuite, Sage Intacct, or SAP with layered approval rules or purchase-order matching: Stampli sits on top of the existing ERP with no migration, custom-quoted by volume.
• Clients outside the United States: none of the three fit. All three handle US domestic payment rails only; BILL and Stampli add international wire support on outbound payments, and Melio supports cross-border vendor payments in USD and local currencies.

The three-question filter

1. What ledger or ERP does the client run?

Melio stops at QuickBooks and Xero. Nothing else. If a client runs NetSuite, Sage Intacct, SAP, or Microsoft Dynamics, Melio is out regardless of price, and the choice narrows to BILL or Stampli. BILL covers QuickBooks, Xero, NetSuite, Sage Intacct, and Microsoft Dynamics natively, with automatic two-way sync for QuickBooks Online and Xero starting on its Team tier. Stampli goes further still, connecting to more than 70 systems including SAP, Acumatica, and Workday, and it sits on top of whatever ERP the client already runs rather than requiring a switch.

2. How complex does the approval chain need to be?

Melio's approval workflows start at the $25 Core plan and stay simple: routing and W-9 collection, nothing layered. BILL runs rule-based approval routing that covers most firms' needs without much configuration. Stampli is the deepest of the three here: single approver, multi-step, threshold-based, department-based, project-based, vendor-based, and conditional combinations, plus purchase-order matching that flags mismatches automatically. If a client's approval process genuinely has that many branches, or the audit trail on who-approved-what needs to live with the bill itself rather than scattered across email and chat, Stampli is built for that case specifically.

3. What does the per-client budget actually allow?

Melio is free at the entry tier, adds a $10-per-user fee on the Core and Boost tiers, and tops out at $80 a month with no per-user fee once a client reaches Unlimited. BILL runs $49 to $89 per user per month, softened by 10 to 20 percent wholesale pricing on the accountant program. Stampli quotes custom, and a mid-market client should expect $8,000 to $25,000 in year-one spend across software and setup, with no free trial to test the waters first. A client generating a handful of bills a month cannot justify Stampli's pricing regardless of how well the approval engine fits; a mid-market client with real volume and multiple approvers rarely finds BILL's per-seat model or Melio's QuickBooks-and-Xero ceiling sufficient.

BILL: per-user pricing with the deepest accountant program

BILL runs the full AP and AR cycle: a vendor bill arrives by email or scan, BILL reads it, routes it through an approval queue, and pays out by ACH, card, or check once approved, posting the transaction back to QuickBooks, Xero, NetSuite, Sage Intacct, or Microsoft Dynamics without re-keying. Pricing tiers from Essentials ($49 per user per month, manual ledger sync) through Team ($65, automatic two-way sync for QuickBooks Online and Xero) to Corporate ($89, procurement and custom approval policies) with a custom Enterprise tier above that for multi-entity accounts. A free Spend and Expense tier adds corporate cards funded by interchange rather than a subscription.

The accountant partner program is BILL's strongest differentiator for a multi-client practice: bulk client management, a management console for oversight across the roster, and wholesale pricing at 10 to 20 percent off based on volume. What it does not do is AI-driven line-item coding the way Stampli does; BILL's auto-coding works well on recurring suppliers but leans more on rule-based routing than judgment calls. BILL is US-only, covering domestic ACH, wire, and check with international wire support for outbound payments, and it offers a free trial on both AP and AR plans.

Stampli: custom-quoted approval depth without an ERP migration

Stampli's defining feature is keeping every bill discussion, approval decision, and audit trail attached to the invoice itself rather than spread across a separate workflow tool, email, and chat. When a manager opens a flagged bill, the full history, who asked what, who approved, who pushed back, is right there on the document. That matters most for clients with approval processes too layered for a generic rules engine: threshold-based routing, department or project-based approvers, vendor-specific rules, and combinations of all four.

Because Stampli sits on top of the client's existing ERP rather than replacing it, there is no migration to plan for. It connects to more than 70 systems, with a Built for NetSuite verified connection and Sage Recommended Solution status for Sage Intacct, plus API connections to SAP, QuickBooks, and Microsoft Dynamics. Purchase orders match against invoice lines automatically, with mismatches flagged for review, a feature neither BILL nor Melio offers at this depth. The tradeoff is transparency: Stampli publishes no pricing and offers no free trial. Quotes are based on invoice volume and integration scope, and a mid-market client should plan for $8,000 to $25,000 in year-one spend. For a client with under 100 bills a month, that cost rarely pencils out against BILL or Melio.

Melio: free tier for solo bookkeepers and micro clients

Melio covers vendor bill pay and invoicing for small businesses and the accountants who work with them, with a genuinely free Go tier: one user, five ACH payments a month, AI bill capture, and free QuickBooks or Xero sync. Core at $25 a month adds batch payments, approval workflows, W-9 collection, and 1099 automation. Boost at $55 brings QuickBooks Desktop sync and advanced approval rules. Unlimited at $80 drops per-user fees entirely, useful for a firm adding staff faster than it adds clients.

The limitation is ledger reach: QuickBooks and Xero only, nothing else. A client on NetSuite or Sage Intacct needs BILL or Stampli regardless of budget. Melio's partner program tiers from Bronze to Diamond with 30 to 45 percent discounts on firm-billed plans and a free Boost plan for the firm's own internal use, which makes it worth adopting even for a firm whose real client volume sits with BILL or Stampli. A 30-day free trial covers the full feature set, and cross-border vendor payments are available in USD and local currencies even though the firm and client must be US-based.

Feature and pricing comparison

Prices reflect what each vendor publishes as of this writing. Confirm the current number on the vendor's own pricing page before committing a client to a contract, and get a written quote from Stampli before assuming it fits the budget.

Ledger fit narrows this before approval depth or price do

Check the client's ledger first. Melio's QuickBooks-and-Xero ceiling rules it out immediately for anything on NetSuite, Sage Intacct, SAP, or Dynamics, which leaves BILL or Stampli. Between those two, the question shifts to how layered the approval process actually needs to be: BILL's rule-based routing covers most firms without extra configuration, and Stampli's threshold, department, and vendor-based combinations exist for the clients whose approval chain a generic engine cannot represent. Budget follows from there rather than leading it. A client whose approval needs justify Stampli's depth usually has the invoice volume to justify the custom quote too; a client that does not need that depth is paying for capability sitting unused.

None of the three handle everything an AP client might need. For clients paying vendors across multiple countries, or the broader field of tools priced by invoice volume rather than seats or a flat fee, see the full AP automation software comparison, and browse the AP, AR, and payments category for tools built for cross-border payments or spend intelligence that sit outside this three-way comparison. For the receivables side of the same ledger, Best AI Tools for Accounts Receivable and Cash Collection covers tools built for chasing payment rather than sending it.

Running the filter on three real setups

A solo bookkeeper with a dozen clients, all sole traders on QuickBooks Online paying a handful of bills a month. Ledger says QuickBooks. Approval needs are minimal, one person signs off on everything. Budget is close to zero per client. Answer: Melio, starting on the free Go tier.

A five-person firm managing 30 clients across QuickBooks and Xero, with a couple of clients on Sage Intacct. Ledger fits BILL for the QuickBooks and Xero majority and either BILL or Stampli for the Sage Intacct clients. Approval needs are moderate, a manager reviews and one owner signs off. Budget favors the accountant program's wholesale pricing. Answer: BILL, with its Sage Intacct coverage handling the outliers without a second tool.

A controllership client on NetSuite with department budgets, project codes, and three layers of approval before a bill gets paid. Ledger rules out Melio outright. BILL's rule-based routing would need heavy workarounds to represent three approval layers cleanly. Stampli's threshold and department-based rules were built for exactly this case, and the client's invoice volume is high enough to justify a custom quote. Answer: Stampli.

Common questions

Is BILL or Melio cheaper?

Melio, for a client with light volume. Its Go tier is free for one user and five ACH payments a month, and even its top Unlimited plan at $80 a month has no per-user fee. BILL starts at $49 per user per month with no free tier, so a two-person AP team on BILL runs closer to $100 a month before payment fees. The gap closes once a client needs NetSuite or Sage Intacct sync, which Melio does not offer at any price.

Why won't Stampli publish its pricing?

Stampli prices by invoice volume, user count, and integration scope, all of which vary too much across mid-market clients for a fixed rate card to make sense. The tradeoff for a firm evaluating it is that a real number only comes after a sales call, with year-one spend typically landing between $8,000 and $25,000 for a mid-market client. Firms that want a published number to compare against a budget upfront should start with BILL or Melio instead.

Which of the three works with NetSuite?

BILL and Stampli both connect to NetSuite. BILL's sync covers the core ledger; Stampli holds a Built for NetSuite verified connection and adds purchase-order matching on top. Melio does not connect to NetSuite at all, only QuickBooks and Xero.

Can a firm run more than one of these across its client list?

Yes, and it is common once a client roster spans firm sizes. A typical split runs Melio for the smallest clients where the free tier already covers the volume, and BILL or Stampli for the clients with real invoice volume, multiple approvers, or an ERP that Melio does not reach. There is no requirement to standardize every client onto one platform.

Does any of the three work outside the United States?

No. BILL and Stampli handle US domestic ACH, wire, and check payments, with international wire support for outbound payments to other countries; Melio handles US domestic ACH, card, and check, with cross-border vendor payments available in USD and local currencies. None of the three support UK, Australian, or EU domestic payment rails. Firms with non-US clients typically look at Tipalti or the AP features built into Xero or QuickBooks directly, covered in the full AP automation comparison.

If working through ledger fit, approval depth, and budget by hand feels like more than the decision is worth, the CurateSuite matchmaker takes a few questions about a client's ERP, volume, and approval needs and returns the AP tools that fit, with results shown immediately and no email required.