Billie

Billie is a Berlin-based B2B "buy now, pay later" (BNPL) payment provider that lets merchants offer business buyers invoice purchase, pay-after-delivery, and installment terms at checkout while Billie assumes the credit and fraud risk and pays the merchant out. Its Payment API v2 (paella.billie.io) uses OAuth 2.0 client-credentials and covers checkout sessions, a hosted payment page, direct backend order creation, order management, captures (invoicing), payment confirmation, refunds/credit notes, and a webhook event surface. Billie also ships an embeddable checkout widget, a PHP SDK, e-commerce plugins (Shopware, Magento, WooCommerce, JTL), and partner routes via Klarna, Mollie, Adyen, Stripe, and Kustom. Backed by Creandum and Speedinvest.

Billie publishes 1 API on the APIs.io network. Tagged areas include Company, Fintech, Payments, BNPL, and Buy Now Pay Later.

The Billie catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Billie’s developer surface includes documentation, API reference, getting-started guide, authentication, sandbox, support, engineering blog, and 27 more developer resources.

🌐 Visit website 📡 Source on GitHub
34.7/100 thin Agent 46/100 agent ready Full breakdown ↓
scored 2026-07-20 · rubric v0.4
1 APIs 1 MCP Servers 0 Features
CompanyFintechPaymentsBNPLBuy Now Pay LaterB2BInvoicingCheckoutGermany

API Rating

API Evangelist API Evangelist Rating How this is scored →
scored 2026-07-20 · rubric v0.4
Composite quality — 34.7/100 · thin
Contract Quality 0.0 / 25
Developer Ergonomics 16.1 / 20
Commercial Clarity 4.7 / 20
Operational Transparency 5.1 / 13
Governance 0.0 / 12
Discoverability 8.8 / 10
Agent readiness — 46/100 · agent ready
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
MCP Server 12 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 6 / 6
Agent Skills 5 / 5
Well-Known Catalog 4 / 4
Consent & Bot Identity 3 / 3
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/billie: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs

Billie Payment API

OAuth2 client-credentials REST API for B2B BNPL: checkout sessions, hosted payment page, backend order creation, order management, captures (invoices), payment confirmation, ref...

MCP Servers

billie-mcp.yml

MCP SERVER

Event Specifications

Billie Webhooks

ASYNCAPI

Resources

Get Started 5

Portal, sign-up, and the first successful call

DeveloperPortal
DeveloperPortal
 GettingStarted
GettingStarted
 Sandbox
Sandbox
 SignUp
SignUp
 Login
Login

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

MCPServer
MCPServer
 AgentSkill
AgentSkill
 LLMsTxt
LLMsTxt
 WellKnown
WellKnown

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Webhooks
Webhooks
 Conventions
Conventions
 ErrorCatalog
ErrorCatalog
 Lifecycle
Lifecycle
 Conformance
Conformance
 DataModel
DataModel
 Components
Components

Scroll for all 7

Build 4

SDKs, sample code, and the tooling you integrate with

SDKs
SDKs
 Packages
Packages
 DeclineCodes
DeclineCodes
 GitHubOrganization
GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

VulnerabilityDisclosure
VulnerabilityDisclosure
 Security
Security
 DomainSecurity
DomainSecurity
 Authentication
Authentication
 SecurityTxt
SecurityTxt

Operate 3

Status, limits, changes, and where to get help

StatusPage
StatusPage
 Support
Support
 HelpCenter
HelpCenter

Commercial 1

Pricing, plans, and the legal terms of use

PrivacyPolicy
PrivacyPolicy

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 1

Properties that don't map to a standard resource type

Imprint
Imprint

Source (apis.yml)

apis.yml Raw ↑ 
aid: billie
name: Billie
description: Billie is a Berlin-based B2B "buy now, pay later" (BNPL) payment provider that lets merchants offer business
  buyers invoice purchase, pay-after-delivery, and installment terms at checkout while Billie assumes the credit and fraud
  risk and pays the merchant out. Its Payment API v2 (paella.billie.io) uses OAuth 2.0 client-credentials and covers checkout
  sessions, a hosted payment page, direct backend order creation, order management, captures (invoicing), payment confirmation,
  refunds/credit notes, and a webhook event surface. Billie also ships an embeddable checkout widget, a PHP SDK, e-commerce
  plugins (Shopware, Magento, WooCommerce, JTL), and partner routes via Klarna, Mollie, Adyen, Stripe, and Kustom. Backed
  by Creandum and Speedinvest.
url: https://raw.githubusercontent.com/api-evangelist/billie/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- creandum
- speedinvest
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-18'
tags:
- Company
- Fintech
- Payments
- BNPL
- Buy Now Pay Later
- B2B
- Invoicing
- Checkout
- Germany
apis:
- name: Billie Payment API
  description: 'OAuth2 client-credentials REST API for B2B BNPL: checkout sessions, hosted payment page, backend order creation,
    order management, captures (invoices), payment confirmation, refunds/credit notes, and webhooks.'
  humanURL: https://docs.billie.io/reference/integration-checklist
  baseURL: https://paella.billie.io/api/v2
  properties:
  - type: Documentation
    url: https://docs.billie.io/
  - type: APIReference
    url: https://docs.billie.io/reference/integration-checklist
  - type: Authentication
    url: authentication/billie-authentication.yml
  - type: Webhooks
    url: asyncapi/billie-webhooks.yml
  - type: Sandbox
    url: sandbox/billie-sandbox.yml
  - type: DeclineCodes
    url: errors/billie-decline-codes.yml
  - type: ErrorCatalog
    url: errors/billie-problem-types.yml
  - type: Conventions
    url: conventions/billie-conventions.yml
  - type: Lifecycle
    url: lifecycle/billie-lifecycle.yml
  - type: Conformance
    url: conformance/billie-conformance.yml
  - type: DataModel
    url: data-model/billie-data-model.yml
  - type: MCPServer
    url: mcp/billie-mcp.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: VulnerabilityDisclosure
  url: security/billie-vulnerability-disclosure.yml
- type: Security
  url: https://billie.io/coordinated-vulnerability-disclosure-policy
- type: DomainSecurity
  url: security/billie-domain-security.yml
- type: Website
  url: https://www.billie.io/
- type: DeveloperPortal
  url: https://docs.billie.io/
- type: Documentation
  url: https://docs.billie.io/
- type: APIReference
  url: https://docs.billie.io/reference/integration-checklist
- type: GettingStarted
  url: https://docs.billie.io/docs/get-started-with-billies-api-integration
- type: Authentication
  url: authentication/billie-authentication.yml
- type: SDKs
  url: packages/billie-packages.yml
- type: Packages
  url: packages/billie-packages.yml
- type: Sandbox
  url: sandbox/billie-sandbox.yml
- type: Webhooks
  url: asyncapi/billie-webhooks.yml
- type: MCPServer
  url: mcp/billie-mcp.yml
- type: AgentSkill
  url: skills/_index.yml
- type: LLMsTxt
  url: llms/billie-llms.txt
- type: WellKnown
  url: well-known/billie-well-known.yml
- type: SecurityTxt
  url: well-known/billie-security.txt
- type: Conventions
  url: conventions/billie-conventions.yml
- type: DeclineCodes
  url: errors/billie-decline-codes.yml
- type: ErrorCatalog
  url: errors/billie-problem-types.yml
- type: Lifecycle
  url: lifecycle/billie-lifecycle.yml
- type: StatusPage
  url: https://status.billie.io/
- type: Conformance
  url: conformance/billie-conformance.yml
- type: DataModel
  url: data-model/billie-data-model.yml
- type: Components
  url: components/billie-components.yml
- type: Support
  url: https://help.billie.io/merchant/s/
- type: HelpCenter
  url: https://help.billie.io/merchant/s/
- type: Blog
  url: https://www.billie.io/blog
- type: GitHubOrganization
  url: https://github.com/ozean12
- type: SignUp
  url: https://dashboard.billie.io/public/registration
- type: Login
  url: https://dashboard.billie.io/public/login
- type: PrivacyPolicy
  url: https://www.billie.io/datenschutz
- type: Imprint
  url: https://www.billie.io/impressum
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence