Sezzle

Sezzle is a buy-now-pay-later platform that enables merchants to offer installment payment options at checkout. Its REST APIs support merchant checkout integration, order management, shopper authentication, customer tokenization, and payment installment processing — allowing shoppers to split purchases into four interest-free payments over six weeks.

Sezzle publishes 8 API contracts indexed on the APIs.io network, including Bearer Authentication API, Customer API, Order API, and 5 more. Tagged areas include Buy Now Pay Later, Payments, Installments, Fintech, and Merchant Integration.

The Sezzle catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Sezzle’s developer surface includes engineering blog, authentication, developer portal, GitHub presence, pricing, terms of service, privacy policy, and 16 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

31.8/100 thin ▬ flat Agent 25/100 agent aware Front door AI 1/6 silent Heartbeat 99/100 alive saas Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessPaid

1 published contract

Buy Now Pay Later Payments Installments FintechMerchant IntegrationCheckout

What this lets a business do 1

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

Developer Platform & API Ecosystem Management

BC-4270

Webhooks

POST /webhooks GET /webhooks POST /webhooks/test

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 31.8/100 · thin

Contract Quality 9.8 / 19

Developer Ergonomics 5.0 / 15

Access Clarity 1.9 / 15

Operational Transparency 1.4 / 10

Contract Governance 0.9 / 9

Discoverability 5.0 / 8

Regulatory Posture 3.6 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 25/100 · 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 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 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 0 / 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 Ask about this →
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) Ask about this →
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes Ask about this →
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0 Ask about this →
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document Ask about this →
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented) Ask about this →

8 more unmet checks in the Agent Readiness table above.

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

Access Clarity scores 12.8 — up to +17.4 composite points Ask about this →
Developer Ergonomics scores 33.3 — up to +13.3 composite points Ask about this →
Contract Quality scores 52.0 — up to +12.0 composite points Ask about this →

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.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

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/sezzle/apis.yml: open an issue on github.com/api-evangelist/sezzle 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
MACH & Headless Commerce	builds-on	51.7	-	-
Consumer Lending Licensing (UK, US, Canada credit licence registers)	builds-on	51.7	-	-
E-commerce Extension Marketplaces (Adobe Commerce / Magento, Shopware)	builds-on	51.7	-	-

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 1

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)

APIs 8

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

Sezzle API v1

The legacy Sezzle v1 API for merchants. Supports checkout creation and order completion via redirect-based flow. Deprecated in favor of v2; existing integrations are encouraged ...

Sezzle Bearer Authentication API

The Bearer Authentication API from Sezzle — 1 operation(s) for bearer authentication.

Sezzle Customer API

The Customer API from Sezzle — 4 operation(s) for customer.

Sezzle Order API

The Order API from Sezzle — 7 operation(s) for order.

Sezzle Reports API

The Reports API from Sezzle — 4 operation(s) for reports.

Sezzle Session API

The Session API from Sezzle — 2 operation(s) for session.

Sezzle Token API

The Token API from Sezzle — 2 operation(s) for token.

Sezzle Webhooks API

The Webhooks API from Sezzle — 3 operation(s) for webhooks.

Scroll for all 8

Scroll for all 7

Sezzle API pricing

Not yet checked against Sezzle's own pricing page. Compiled by API Evangelist; confirm before you rely on a figure.

Plan	Price
Standard Merchant Plan merchant	—
Enterprise / Volume Plan enterprise	—

Plan details, limits and sources →

Pricing Plans 1

Published pricing tiers and plan structures.

Plans

2 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Rate Limits

0 limits

RATE LIMITS

FinOps 1

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

Finops

FINOPS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Sezzle Context

12 classes · 60 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Sezzle — jsonschema rules

5 rules · 4 warn-severity 1 info-severity

SPECTRAL

JSON Schema 8

Standalone JSON Schema definitions for this provider's data models.

Address

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

Sezzle Agentic Access

27 operations · 15 acting

AGENTIC

Resources

Get Started 1

Portal, sign-up, and the first successful call

Portal

Portal

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

Build 7

SDKs, sample code, and the tooling you integrate with

GitHub

SDKNode

SDKAndroid

SDKiOS

IntegrationMagento2

IntegrationMagento2

IntegrationWooCommerce

IntegrationWooCommerce

IntegrationShopify

IntegrationShopify

Scroll for all 7

Access & Security 3

Authentication, authorization, and security posture

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 2

Status, limits, changes, and where to get help

RateLimits

RateLimits

MerchantSupport

MerchantSupport

Commercial 5

Pricing, plans, and the legal terms of use

Plans

FinOps

Pricing

Terms

Privacy

Company 2

The organization behind the API

Blog

Blog

Website

Website

Other 2

Properties that don't map to a standard resource type

CapabilityMap

CapabilityMap

Dashboard

Dashboard

Source (apis.yml)

name: Sezzle
description: Sezzle is a buy-now-pay-later platform that enables merchants to offer installment payment options at checkout.
  Its REST APIs support merchant checkout integration, order management, shopper authentication, customer tokenization, and
  payment installment processing — allowing shoppers to split purchases into four interest-free payments over six weeks.
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: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/sezzle.png
url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/apis.yml
version: '0.19'
created: '2026-06-13'
modified: '2026-10-06'
specificationVersion: '0.23'
x-docs-platform: mintlify
x-docs-platform-confidence: medium
x-docs-platform-checked: 2026-10-04
x-docs-hosting: vercel
tags:
- Buy Now Pay Later
- Payments
- Installments
- Fintech
- Merchant Integration
- Checkout
tags_raw:
- Buy Now Pay Later
- BNPL
- Payments
- Installments
- Fintech
- Merchant Integration
- Checkout
apis:
- name: Sezzle API v1
  description: The legacy Sezzle v1 API for merchants. Supports checkout creation and order completion via redirect-based
    flow. Deprecated in favor of v2; existing integrations are encouraged to migrate to v2.
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://docs.sezzle.com/docs/api/v1/v1
  baseURL: https://gateway.sezzle.com/v1
  tags:
  - Payments
  - Checkout
  - Legacy
  properties:
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/v1/v1
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v1
  contact:
  - FN: Sezzle Merchant Support
    url: https://merchant-help.sezzle.com
    email: ''
- aid: sezzle:sezzle-bearer-authentication-api
  name: Sezzle Bearer Authentication API
  description: The Bearer Authentication API from Sezzle — 1 operation(s) for bearer authentication.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Bearer Authentication
  properties:
  - type: OpenAPI
    url: openapi/sezzle-bearer-authentication-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-customer-api
  name: Sezzle Customer API
  description: The Customer API from Sezzle — 4 operation(s) for customer.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Customers
  tags_raw:
  - Customer
  properties:
  - type: OpenAPI
    url: openapi/sezzle-customer-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-order-api
  name: Sezzle Order API
  description: The Order API from Sezzle — 7 operation(s) for order.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Order
  properties:
  - type: OpenAPI
    url: openapi/sezzle-order-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-reports-api
  name: Sezzle Reports API
  description: The Reports API from Sezzle — 4 operation(s) for reports.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Reports
  properties:
  - type: OpenAPI
    url: openapi/sezzle-reports-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-session-api
  name: Sezzle Session API
  description: The Session API from Sezzle — 2 operation(s) for session.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Sessions
  tags_raw:
  - Session
  properties:
  - type: OpenAPI
    url: openapi/sezzle-session-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-token-api
  name: Sezzle Token API
  description: The Token API from Sezzle — 2 operation(s) for token.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Tokens
  tags_raw:
  - Token
  properties:
  - type: OpenAPI
    url: openapi/sezzle-token-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
- aid: sezzle:sezzle-webhooks-api
  name: Sezzle Webhooks API
  description: The Webhooks API from Sezzle — 3 operation(s) for webhooks.
  humanURL: https://docs.sezzle.com/docs/api/intro
  baseURL: https://gateway.sezzle.com/v2
  tags:
  - Webhook
  tags_raw:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/sezzle-webhooks-api-openapi.yml
  - type: Documentation
    url: https://docs.sezzle.com/docs/api/intro
  - type: Sandbox
    url: https://sandbox.gateway.sezzle.com/v2
  - type: Authentication
    url: https://docs.sezzle.com/docs/api/intro
  - type: Plans
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/plans/plans.yml
  - type: RateLimits
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/rate-limits/rate-limits.yml
  - type: FinOps
    url: https://raw.githubusercontent.com/api-evangelist/sezzle/refs/heads/main/finops/finops.yml
common:
- type: Plans
  url: plans/plans.yml
- type: RateLimits
  url: rate-limits/rate-limits.yml
- type: FinOps
  url: finops/finops.yml
- url: https://sezzle.com/news/
  type: Blog
- type: CapabilityMap
  url: capabilities/sezzle-capability-edges.yml
  name: Sezzle Business Capability Map
- type: Website
  url: https://www.sezzle.com/
- type: AgenticAccess
  url: agentic-access/sezzle-agentic-access.yml
- type: VulnerabilityDisclosure
  url: security/sezzle-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/sezzle-domain-security.yml
- type: Authentication
  url: authentication/sezzle-authentication.yml
- type: Portal
  url: https://docs.sezzle.com/
- type: Dashboard
  url: https://dashboard.sezzle.com/merchant
- type: MerchantSupport
  url: https://merchant-help.sezzle.com
- type: GitHub
  url: https://github.com/sezzle
- type: SDKNode
  url: https://github.com/sezzle/sezzle-node
- type: SDKAndroid
  url: https://github.com/sezzle/sezzle-merchant-sdk-android
- type: SDKiOS
  url: https://github.com/sezzle/sezzle-merchant-sdk-ios
- type: IntegrationMagento2
  url: https://github.com/sezzle/sezzle-magento2
- type: IntegrationWooCommerce
  url: https://docs.sezzle.com/
- type: IntegrationShopify
  url: https://apps.shopify.com/sezzle-payments
- type: Pricing
  url: https://sezzle.com/pricing
- type: Terms
  url: https://sezzle.com/terms-of-service
- type: Privacy
  url: https://sezzle.com/privacy-policy
maintainers:
- FN: API Evangelist
  url: https://apievangelist.com
  email: kin@apievangelist.com

Sezzle API — frequently asked questions

Does Sezzle have an API?

Yes. APIs.io lists 8 APIs from Sezzle, including Sezzle API v1, Sezzle Bearer Authentication API and Sezzle Customer API, and 5 more.

Is there an OpenAPI specification for the Sezzle API?

Yes. APIs.io indexes 7 OpenAPI specifications for Sezzle, each linked for download from this page.

How do I authenticate with the Sezzle API?

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

How much does the Sezzle API cost?

APIs.io lists 2 pricing plans for Sezzle, with each plan's price, limits and inclusions under Pricing on this page.

Is the Sezzle API ready for AI agents?

Sezzle has a Kin Score of 31.8 out of 100 (thin) and an Agent Readiness score of 24.8 (agent-aware), scored by API Evangelist on 2026-11-13.

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