BILL website screenshot

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 10 APIs on the APIs.io network, including v3 API, Authentication API, Bills API, and 7 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 12 more developer resources.

🌐 Visit website 📡 Source on GitHub
41.3/100 developing ▬ flat Agent 20/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0
1 APIs
Accounts PayableAccounts ReceivableSpend ManagementExpense ManagementPaymentsBill PayFinancial OperationsFintech

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0
Composite quality — 41.3/100 · developing
Contract Quality 10.6 / 19
Developer Ergonomics 7.0 / 15
Access Clarity 6.7 / 15
Operational Transparency 1.2 / 10
Contract Governance 1.2 / 9
Discoverability 5.0 / 8
Regulatory Posture 4.7 / 15
Create-or-Update Ergonomics 0.0 / 10
Agent readiness — 20/100 · 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
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/.
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 github.com/api-evangelist/bill: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

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 11

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

API Collection

OPEN COLLECTION

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 11

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 API 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

40 operations · 26 acting

AGENTIC

Resources

Get Started 4

Portal, sign-up, and the first successful call

Sandbox
Sandbox
 GettingStarted
GettingStarted
 DeveloperPortal
DeveloperPortal
 Signup
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 3

Pricing, plans, and the legal terms of use

PrivacyPolicy
PrivacyPolicy
 TermsOfService
TermsOfService
 Pricing
Pricing

Company 3

The organization behind the API

Blog
Blog
 Website
Website
 LinkedIn
LinkedIn

Source (apis.yml)

apis.yml Raw ↑ 
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: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/bill.png
tags:
- Accounts Payable
- Accounts Receivable
- Spend Management
- Expense Management
- Payments
- Bill Pay
- Financial Operations
- Fintech
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: 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

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