BILL

BILL (formerly Bill.com) is a cloud-based financial operations platform for small and midsize businesses that automates accounts payable, accounts receivable, and spend & expense management. The BILL API Platform exposes these workflows through the BILL v3 REST API and embeddable BILL Elements UI components, enabling partners and ERPs to integrate bill capture, approvals, payments, and real-time event notifications via webhooks. The API uses session-based authentication with API keys and developer keys against production and sandbox gateways.

BILL publishes 11 API contracts indexed on the APIs.io network, including v3 API, Authentication API, Bills API, and 8 more. Tagged areas include Accounts Payable, Accounts Receivable, Spend Management, Expense Management, and Payments.

The BILL catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

BILL’s developer surface includes engineering blog, sandbox, changelog, getting-started guide, authentication, documentation, API reference, and 14 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

53.9/100 developing ▲ 6.1 Agent 24/100 agent aware Front door AI 5/6 prominent saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract

Accounts Payable Accounts Receivable Spend Management Expense Management Payments Bill Pay Financial Operations Fintech Accounting

What this lets a business do 1

Business capabilities this provider's published APIs can perform, derived from its own contracts. Browse all capabilities →

Financial Management

BC-200

BillsCustomersInvoicesPaymentsVendors

POST /bills POST /invoices POST /invoices/{invoiceId}/send POST /vendors

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 53.9/100 · developing

Contract Quality 9.8 / 19

Developer Ergonomics 10.4 / 15

Access Clarity 12.6 / 15

Operational Transparency 2.3 / 10

Contract Governance 1.2 / 9

Discoverability 4.8 / 8

Regulatory Posture 2.7 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 24/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 6 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Payments regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link

8 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Contract Quality scores 52.1 — up to +12.0 composite points
Contract Governance scores 13.6 — up to +10.4 composite points
Operational Transparency scores 23.7 — up to +9.9 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/bill/apis.yml: open an issue on github.com/api-evangelist/bill to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Accounting and Finance Ops	regulated	36.4 (thin)	-	-
Procurement and B2B Buying (source-to-pay suites, spend management)	regulated	36.4 (thin)	-	-
Canada RPAA Payment Service Providers (Bank of Canada registry + Payments Canada)	regulated	36.4 (thin)	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Standards implemented 2

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OpenAPI

measured — observed by APIs.io (published)

AsyncAPI

measured — observed by APIs.io (published)

APIs 11

Individual APIs this provider publishes, each with its own machine-readable definition.

BILL v3 API

REST API providing full-breadth access to BILL's Accounts Payable, Accounts Receivable, and Spend & Expense capabilities including bills, invoices, vendors, customers, payments,...

BILL Elements

Low-code, embeddable UI components that surface the BILL Accounts Payable workflow inside partner applications with minimal development effort.

BILL Authentication API

The Authentication API from BILL — 5 operation(s) for authentication.

BILL Bills API

The Bills API from BILL — 4 operation(s) for bills.

BILL Customers API

The Customers API from BILL — 3 operation(s) for customers.

BILL Funding Accounts API

The Funding Accounts API from BILL — 2 operation(s) for funding accounts.

BILL Invoices API

The Invoices API from BILL — 3 operation(s) for invoices.

BILL Organizations API

The Organizations API from BILL — 2 operation(s) for organizations.

BILL Payments API

The Payments API from BILL — 5 operation(s) for payments.

BILL Vendors API

The Vendors API from BILL — 3 operation(s) for vendors.

BILL Webhooks API

The Webhooks API from BILL — 2 operation(s) for webhooks.

Scroll for all 11

Open Collections 10

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

BILL v3 Authentication API

OPEN COLLECTION

BILL v3 Authentication Bills API

OPEN COLLECTION

BILL v3 Authentication Customers API

OPEN COLLECTION

BILL v3 Authentication Funding Accounts API

OPEN COLLECTION

BILL v3 Authentication Invoices API

OPEN COLLECTION

BILL v3 Authentication Organizations API

OPEN COLLECTION

BILL v3 Authentication Payments API

OPEN COLLECTION

BILL v3 Authentication Vendors API

OPEN COLLECTION

BILL v3 Authentication Webhooks API

OPEN COLLECTION

BILL v3 API

OPEN COLLECTION

Scroll for all 10

BILL API pricing

Prices published by BILL, read 2026-10-28 from www.bill.com/product/pricing.

Plan	Price
Essentials	$49 user/ month Includes: AP & AR features, manual CSV integration, API access
Team	$65 user/ month Includes: Automatic 2-way sync with QuickBooks/Xero, custom user roles, cash flow forecasting
Corporate	$89 user/ month Includes: AP, AR, Procurement, SSO, multi-entity
Enterprise	Custom Pricing Includes: All Corporate features plus ERP syncs, dual control, priority support, API access
Spend & Expense	$0 user/ month Includes: Cards, budgets, expense management, API and developer resources
BILL AP & AR Partner (accountants)	$49/month Includes: Accountant console, wholesale client subscription pricing
BILL Spend & Expense Partner	$0 Includes: Free-to-use for firm and clients

Plan details, limits and sources →

Billed by: user · FinOps profile →

Pricing Plans 2

Published pricing tiers and plan structures.

Bill Plans Pricing

7 plans

PLANS

Bill Price Estimates

0 plans

PLANS

Service Levels 1

Uptime the provider promises or reports, as SLA4OAI. Read from its own pages; APIs.io runs no monitors.

BILL

SLA

FinOps 1

Cost, billing, and metering signals for API financial operations.

Bill Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

BILL Webhooks

Outbound webhook event notifications delivered by the BILL v3 API Platform to subscriber `notificationUrl` endpoints. Subscribers register through the BILL v3 webhook subscripti...

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

BILL — asyncapi rules

8 rules · 1 errors 6 warnings 1 info

SPECTRAL

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Bill Authentication

apiKey · 1 scheme

SECURITY

Bill Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Bill Agentic Access

40 operations · 26 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

Sandbox

GettingStarted

DeveloperPortal

Signup

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

LlmsText

LlmsText

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Webhooks

Webhooks

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

ChangeLog

ChangeLog

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

PrivacyPolicy

TermsOfService

Pricing

Company 3

The organization behind the API

Blog

Blog

Website

Website

LinkedIn

Other 1

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Source (apis.yml)

aid: bill
name: BILL
description: BILL (formerly Bill.com) is a cloud-based financial operations platform for small and midsize businesses that
  automates accounts payable, accounts receivable, and spend & expense management. The BILL API Platform exposes these workflows
  through the BILL v3 REST API and embeddable BILL Elements UI components, enabling partners and ERPs to integrate bill capture,
  approvals, payments, and real-time event notifications via webhooks. The API uses session-based authentication with API
  keys and developer keys against production and sandbox gateways.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/bill.png
x-docs-platform: readme
x-docs-platform-confidence: high
x-docs-platform-checked: 2026-09-20
tags:
- Accounts Payable
- Accounts Receivable
- Spend Management
- Expense Management
- Payments
- Bill Pay
- Financial Operations
- Fintech
- Accounting
url: https://raw.githubusercontent.com/api-evangelist/bill/refs/heads/main/apis.yml
created: '2026-05-11'
modified: '2026-05-30'
specificationVersion: '0.23'
apis:
- aid: bill:v3-api
  name: BILL v3 API
  description: REST API providing full-breadth access to BILL's Accounts Payable, Accounts Receivable, and Spend & Expense
    capabilities including bills, invoices, vendors, customers, payments, approvals, and webhook event notifications. Production
    calls are made to https://gateway.prod.bill.com/connect/v3 with sandbox at https://gateway.stage.bill.com/connect/v3.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Accounts Payable
  - Accounts Receivable
  - Spend Management
  - Payments
  - Webhook
  tags_raw:
  - Accounts Payable
  - Accounts Receivable
  - Spend Management
  - Payments
  - Webhooks
  properties:
  - type: Documentation
    url: https://developer.bill.com/docs/home
  - type: APIReference
    url: https://developer.bill.com/reference
  - type: GettingStarted
    url: https://developer.bill.com/docs/bill-v3-api-get-started
  - type: PostmanCollection
    url: https://www.postman.com/bill-api-platform/bill-api-platform-workspace/overview
  - type: AsyncAPI
    url: https://raw.githubusercontent.com/api-evangelist/bill/refs/heads/main/asyncapi/bill-webhooks-asyncapi.yml
- aid: bill:elements
  name: BILL Elements
  description: Low-code, embeddable UI components that surface the BILL Accounts Payable workflow inside partner applications
    with minimal development effort.
  humanURL: https://developer.bill.com/docs/home
  tags:
  - Embeddable UI
  - Accounts Payable
  properties:
  - type: Documentation
    url: https://developer.bill.com/docs/home
- aid: bill:bill-authentication-api
  name: BILL Authentication API
  description: The Authentication API from BILL — 5 operation(s) for authentication.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Authentication
  properties:
  - type: OpenAPI
    url: openapi/bill-authentication-api-openapi.yml
- aid: bill:bill-bills-api
  name: BILL Bills API
  description: The Bills API from BILL — 4 operation(s) for bills.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Bills
  properties:
  - type: OpenAPI
    url: openapi/bill-bills-api-openapi.yml
- aid: bill:bill-customers-api
  name: BILL Customers API
  description: The Customers API from BILL — 3 operation(s) for customers.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Customers
  properties:
  - type: OpenAPI
    url: openapi/bill-customers-api-openapi.yml
- aid: bill:bill-funding-accounts-api
  name: BILL Funding Accounts API
  description: The Funding Accounts API from BILL — 2 operation(s) for funding accounts.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Funding Accounts
  properties:
  - type: OpenAPI
    url: openapi/bill-funding-accounts-api-openapi.yml
- aid: bill:bill-invoices-api
  name: BILL Invoices API
  description: The Invoices API from BILL — 3 operation(s) for invoices.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Invoices
  properties:
  - type: OpenAPI
    url: openapi/bill-invoices-api-openapi.yml
- aid: bill:bill-organizations-api
  name: BILL Organizations API
  description: The Organizations API from BILL — 2 operation(s) for organizations.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Organization
  tags_raw:
  - Organizations
  properties:
  - type: OpenAPI
    url: openapi/bill-organizations-api-openapi.yml
- aid: bill:bill-payments-api
  name: BILL Payments API
  description: The Payments API from BILL — 5 operation(s) for payments.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Payments
  properties:
  - type: OpenAPI
    url: openapi/bill-payments-api-openapi.yml
- aid: bill:bill-vendors-api
  name: BILL Vendors API
  description: The Vendors API from BILL — 3 operation(s) for vendors.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Vendors
  properties:
  - type: OpenAPI
    url: openapi/bill-vendors-api-openapi.yml
- aid: bill:bill-webhooks-api
  name: BILL Webhooks API
  description: The Webhooks API from BILL — 2 operation(s) for webhooks.
  humanURL: https://developer.bill.com/docs/bill-v3-api-get-started
  baseURL: https://gateway.prod.bill.com/connect/v3
  tags:
  - Webhook
  tags_raw:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/bill-webhooks-api-openapi.yml
common:
- type: Plans
  url: plans/bill-plans-pricing.yml
- type: CapabilityMap
  url: capabilities/bill-capability-edges.yml
  name: BILL Business Capability Map
- type: Blog
  url: https://www.bill.com/blog
- type: Webhooks
  url: https://developer.bill.com/docs/webhooks
- type: Sandbox
  url: https://developer.bill.com/docs/sandbox-bank-account-setup
- type: ChangeLog
  url: https://developer.bill.com/changelog
- type: PrivacyPolicy
  url: https://www.bill.com/privacy
- type: TermsOfService
  url: https://www.bill.com/legal/terms-of-service
- type: GettingStarted
  url: https://developer.bill.com/docs/get-started-in-production
- type: AgenticAccess
  url: agentic-access/bill-agentic-access.yml
- type: DomainSecurity
  url: security/bill-domain-security.yml
- type: Authentication
  url: authentication/bill-authentication.yml
- type: Website
  url: https://www.bill.com
- type: DeveloperPortal
  url: https://developer.bill.com
- type: Documentation
  url: https://developer.bill.com/docs/home
- type: APIReference
  url: https://developer.bill.com/reference
- type: Pricing
  url: https://www.bill.com/pricing
- type: Signup
  url: https://app.bill.com/Signup
- type: Support
  url: https://developersupport.bill.com
- type: LinkedIn
  url: https://www.linkedin.com/company/bill-com
- type: LlmsText
  url: https://developer.bill.com/llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

BILL API — frequently asked questions

Does BILL have an API?

Yes. APIs.io lists 11 APIs from BILL, including BILL v3 API, BILL Elements and BILL Authentication API, and 8 more.

Is there an OpenAPI specification for the BILL API?

Yes. APIs.io indexes 9 OpenAPI specifications for BILL, each linked for download from this page.

How do I authenticate with the BILL API?

BILL uses bearer-token authentication (apiKey · 1 scheme). The details are profiled on APIs.io as Bill Authentication.

How much does the BILL API cost?

BILL publishes its prices; its Essentials plan is $49 user/ month as of 2026-10-28. APIs.io lists 7 pricing plans for BILL, with each plan's price, limits and inclusions under Pricing on this page.

Is the BILL API ready for AI agents?

BILL has a Kin Score of 53.9 out of 100 (developing) and an Agent Readiness score of 24.4 (agent-aware), scored by API Evangelist on 2026-11-06.

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