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

38.6/100 thin ▬ flat Agent 24/100 agent aware saas Full breakdown ↓
scored 2026-08-30 · rubric v0.17.2

AccessSelf serve

1 APIs 1 MCP Servers

Company Fintech Payments BNPL Buy Now Pay Later B2B Invoicing Checkout Germany

Kin Score

Kin Score How this is scored →
scored 2026-08-30 · rubric v0.17.2

Composite quality — 38.6/100 · thin

Contract Quality 9.1 / 21

Developer Ergonomics 9.2 / 17

Access Clarity 2.9 / 17

Operational Transparency 3.5 / 11

Contract Governance 0.5 / 10

Discoverability 6.5 / 9

Regulatory Posture 6.3 / 15

Agent readiness — 24/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 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 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 Surface 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.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% 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/. 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 1

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

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 1

Model Context Protocol servers that expose these APIs to AI agents.

Get Started 5

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

Sandbox

SignUp

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

AgentSkill

LLMsTxt

WellKnown

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Webhooks

Conventions

ErrorCatalog

Lifecycle

Conformance

DataModel

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

DomainSecurity

Authentication

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)

aid: billie
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: self-serve
  trial: false
  try_now: false
  public: false
  label: Self-serve signup
  confidence: medium
  source:
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/billie.png
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: '0.23'
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

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