Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →

Strong 6 Solid coverage with minor gaps

Candid Health Patient Collections APIManage patient invoicing, payments, refunds, and accounts receivable. Automates patient billing workflows a...65.8 Zoho InvoiceThe Zoho Invoice API allows you to perform all the operations that you do with the web client. It is built ...65.1 Telr QuickLink and E-Invoicing APIRemote creation of QuickLink payment links and e-invoices with extra data fields, for merchants who collect...62.6 HyperPay HyperBillHyperBill issues invoices and shareable payment links that collect payment through the HyperPay platform wi...55.6 Flywire Invoicing APIREST API for the Flywire Invoicing Platform — contacts, invoices, credit notes and invoice payments for a c...55.0 Pabbly Subscription Billing APIREST API for Pabbly Subscription Billing — 95 documented operations across customers, subscriptions, produc...54.8

Developing 13 Usable, with meaningful gaps to close

AccountsIQ Integration API 2.0The current AIQ SOAP 1.1 integration web service. 219 operations covering customers, suppliers, stock items...54.2 Proactis Invoice APIRetrieve invoices from Proactis, receive them pushed to your own endpoint as they reach a configured status...54.0 Coupa Invoicing APIThe Coupa Invoicing API provides RESTful endpoints for creating, updating, and querying invoices associated...53.5 Autopay Accounting APIThe Autopay Accounting API provides Autopay invoicing data to external accounting and ERP systems, enabling...52.1 Tabs Platform APIREST API for the Tabs revenue automation platform that exposes the core data model of customers, contracts,...50.7 AdvicePay APIThe AdvicePay REST API (v1.0.1) exposes the fee-for-service billing platform to integrators: admins, adviso...50.4 Deskera Books APIREST API for Deskera Books, the cloud ERP and accounting product — contacts, products, accounts, invoices, ...50.1 Semble Billing & Payments APIGraphQL surface for practice finances — invoices, invoice payments and line items, account statements, prod...49.4 Spotnana Invoicing APIAPIs to manage invoicing.47.5 Request Finance AP and AR APIThe Accounts Payable and Receivable REST API for issuing invoices, accepting crypto and fiat payments, runn...43.6 GuestReady Invoicing APIThe invoicing API from GuestReady — 2 operation(s) for invoicing.43.4 Harvest API v2REST API for managing clients, projects, tasks, time entries, expenses, invoices, estimates, and users in H...42.6 Depositphotos Enterprise APIThe Enterprise API provides organizations with full content licensing workflows including searching 331M+ a...39.8

Thin 29 Limited public surface area

FreeAgent REST APIRESTful API for the FreeAgent cloud accounting platform. Provides full access to invoices, estimates, conta...38.0 CyberSource Invoicing APICreates and manages payment invoices with customizable fields, due dates, and customer information. Generat...37.5 Billogram v2 APIRESTful JSON API for managing invoices (billograms), customers, items, credit invoices, payment sources, of...37.4 Wave Financial GraphQL APIGraphQL API providing programmatic access to Wave accounting features including businesses, customers, invo...36.4 Outpost Merchant of Record APIREST API to issue proforma invoices for B2B customers paying by bank transfer, receive settlement webhooks,...35.9 Hnry Platform APIThe REST API behind the Hnry app. It backs the Hnry iOS/Android clients and the published Hnry Zapier integ...35.3 Bakuraku APIREST API for the Bakuraku (バクラク) back-office suite. Publicly documented capabilities are retrieval and list...35.2 Zenskar APIZenskar's REST API for billing, contracts, usage metering, invoicing, payments, credit notes, and accountin...35.1 Fatora REST APIFatora's REST API for hosted-checkout payment collection, card tokenization, refunds and payment verificati...34.4 Cora APICora's transactional banking API for Direct Integration: registered boleto and carnê (installment) issuance...34.2 QuickBooksREST API for managing QuickBooks Online accounting entities including Customer, Vendor, Employee, Item, Inv...34.2 UNFI EDI IntegrationUNFI supports Electronic Data Interchange (EDI) for automated exchanges of purchase orders, invoices, and f...33.5 MyFatoorah Invoicing APICreate invoices and payment links.32.5 MakeLeaps APIREST API for the MakeLeaps cloud invoicing platform. Authenticated with OAuth 2.0 client-credentials agains...32.4 National Australia Bank (NAB) Gateway Payments APINAB's first-party merchant payments REST API platform (the NAB Gateway / NAB Transact developer portal at n...32.4 Taulia Supplier APIThe supplier-side integration API described in the SAP Taulia Description of Software Services. It exchange...31.5 FreshBooks REST APIREST API for FreshBooks providing CRUD access to clients, invoices, estimates, expenses, projects, time ent...31.1 FreshBooks Webhooks (Callbacks API)Event delivery surface for the FreshBooks Callbacks API. Subscribers register an HTTPS endpoint, complete a...31.1 Geidea Pay by Invoice APICreate, update, fetch, delete, and send payment invoices (KSA) that customers settle through a Geidea-hoste...30.2 Geidea Pay by Link APIProgrammatically create, update, fetch, delete, and send (by email or SMS) shareable payment links so custo...30.2 Exact Online REST / OData APIREST and OData API (v1) for Exact Online covering financials, sales, purchasing, inventory, HRM, CRM, proje...29.6 Cegid Click & Finance APIREST API for the Koalaboox / Cegid Click & Finance invoicing and invoice-financing platform. Resource-orien...29.5 Oyster HR APIREST API for global employment operations including hiring, payroll, benefits, time off, expenses, invoicin...29.0 Clear Books REST APIRESTful API for integrating with Clear Books accounting software to manage invoices, payments, contacts, ba...28.9 NYISO Finance Invoicing APIThe Invoicing component of NYISO's Finance APIs, retrieving daily reconciliation data for both settlements ...28.2 Iugu APIRESTful API providing 140+ endpoints for payment processing, customer management, invoicing, subscriptions,...27.4 Accelo REST APIREST API for Accelo with CRUD access to companies, contacts, activities, tasks, projects (jobs), milestones...27.1 Holded Invoicing APIThe Invoicing API from Holded — 15 operation(s) for invoicing.27.0 Holded REST APIREST API for managing invoicing, contacts, products, accounting, projects, employees, and CRM records insid...27.0

Emerging 9 Early or largely undocumented

Zoho Invoice APIREST API for managing organizations, contacts, items, invoices, estimates, credit notes, recurring invoices...25.8 Novo PaymentsNovo money movement - invoicing, ACH transfers, and faster payouts (Express ACH). These capabilities are de...25.3 Fawaterak API v2REST API for the EasyPay/Fawaterak payment gateway. Authenticated with a vendor Bearer token, it lists avai...25.1 Found InvoicingCreate and send invoices, track their status, and get paid directly into the Found account, with invoice in...22.0 VAT API v2REST API for EU and UK VAT compliance including VAT rate lookups by country, VAT number validation against ...21.3 BillDesk CX+ Deep APIDirect REST API access for advanced payment processing, giving merchants full control over checkout UX. Sup...21.1 Certinia Billing Central APIGlobal Apex service classes for subscription and usage billing. BillingService, BillingDocumentsService, Bi...20.8 Heartland Bill Pay APIThe Heartland Bill Pay API enables invoice and bill payment processing for merchants accepting recurring or...15.6 UBS QR Portal APIA free programmatic QR-bill creation service supporting the Swiss QR payment standard. Returns QR bills in ...11.3

Minimal 5 Almost no public developer surface

LEAP Time & Billing APIModeled time recording, invoicing, and billing surface, evidenced by LEAP's own marketed "automatic timekee...9.1 Knight-Swift EDI IntegrationKnight-Swift Transportation supports EDI integration for freight tendering, shipment tracking, and invoicin...8.9 CN eBillCN eBill is the customer tool for managing rail freight invoices, account statements, and online bill payme...8.6 ServicingLease and loan servicing covering invoicing, collections, portfolio management, and asset-level financial t...8.0 xCBL — XML Common Business LibraryxCBL 4.0 is a royalty-free library of XML business documents and reusable components for business-to-busine...0.0

Companies reaching this through an API (32)

These companies publish an API, specification or operation carrying “Invoicing” but do not classify their business under it. Listed unranked and kept out of the count above, because one tagged operation is not a statement about what a company does.

Score breakdown

Frequency

65.2

log-scaled weighted occurrences

Breadth

4.5

spread across providers

Quality lift

43.4

mean composite of providers using it

Cohesion

24.0

strength of nearest seed neighbor

Where this tag sits

173 providers carry this tag directly, and 188 counting the 1 narrower tag below — 15 more to reach.

Accounting broader E-Invoicing 27 providers

Where this tag comes from

Provider tag173

Api tag64

Openapi tag3

Openapi op tag33

Cohort brief

Auto-generated

The 171 providers in the APIs.io catalog tagged Invoicing, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.

Providers

171

all scored

Mean Kin Score

35.4

+12.5 vs catalog 22.9

Mean Agent Readiness

22.8

+10.9 vs catalog 11.9

Spread

0–75.4

median 35.1 · σ 15.4

How the 171 split by band

Exemplar 2Strong 18Developing 42Thin 64Emerging 37Minimal 8

Facet averages, against the whole catalog

Facet	This cohort	Catalog	Difference	Scored
Contract Quality	34.2	17.6	+16.6	171
Access Clarity	40.4	26.5	+13.9	171
Developer Ergonomics	36.4	23.2	+13.2	171
Operational Transparency	24.5	13.7	+10.8	171
Discoverability	65.6	58.1	+7.5	171
Contract Governance	7.9	6.3	+1.6	171

A facet is averaged over the members that carry it, not over the whole cohort — the “Scored” column is that count. Averaging an absent facet as zero would score our own coverage gaps as the providers’ posture.

What this cohort publishes

Artifact	This cohort	Catalog	Difference
MCP server (any)	22%	14%	+8
MCP server (first-party)	22%	12%	+10
Agent Skills	0%	0%	0
OAuth scopes	25%	11%	+14
Security	99%	98%	+1
Arazzo workflows	1%	2%	-1
Governance rules	14%	14%	0

mcp_pct counts any mcp/ artifact including ones API Evangelist derived from the provider OpenAPI; mcp_first_party_pct counts only servers the provider publishes. Prefer the latter.

Top by Kin Score

1 Square 75.4
2 Stax 72.4
3 Tradeshift 64.7
4 Visma 64.2
5 Resolve 63.7
6 Agave 61.3
7 Slash 61
8 Lili 60.8
9 Solvimon 60.7
10 FieldPulse 59.3

Work with this as data

Every tag here is available over the APIs.io API and to AI agents over MCP.

MCP server

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https://apis.io/mcp

Tools for tags

7 MCP tools reach this

find_tagsBrowse and filter every tag in the catalog.
get_cohortThis tag as a scored cohort — every provider carrying it, with scores.
cohort_statsPRO — the distribution across this tag: mean, median, band split, adoption rates.
cohort_rankingsPRO — the leaderboard, on composite AND agent-readiness axes.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

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This tag

curl "https://apis.io/api/v1/tags/invoicing"

All tags

curl "https://apis.io/api/v1/tags?limit=25"

As a scored cohort

curl "https://apis.io/api/v1/cohorts/tag/invoicing"

The distribution (Pro)

curl "https://apis.io/api/v1/cohorts/tag/invoicing/stats" \
  -H "X-API-Key: $APIS_IO_KEY"

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Invoicing

Providers using this tag (173)

APIs with this tag (62)