Prosper

Prosper Marketplace operates one of the largest peer-to-peer (marketplace) lending platforms in the United States, matching individual and institutional investors with consumers seeking personal loans, and also offering a HELOC and a credit-card product. For investors, Prosper publishes a RESTful Investor API that lets individual, institutional, and third-party agents connect directly to the platform to view account balances, search active loan listings, place orders (bids) to purchase Notes, and track owned Notes, loans, and payments. The API uses OAuth 2.0 over SSL with comprehensive filtering and sorting, and offers a sandbox environment for integration testing. This profile was surfaced as a portfolio company of Emergence Capital, IVP, and QED Investors and enriched from Prosper's public developer documentation.

Prosper publishes 1 API on the APIs.io network. Tagged areas include Company, Fintech, Lending, Peer-to-Peer Lending, and Marketplace Lending.

Prosper’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, signup flow, pricing, and 13 more developer resources.

🌐 Visit website 📡 Source on GitHub

28.7/100 thin ▬ flat Agent 10/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessSelf serve

1 APIs

Company Fintech Lending Peer-to-Peer Lending Marketplace Lending Investing Personal Loans Consumer Credit Financial-Services

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 28.7/100 · thin

Contract Quality 0.0 / 25

Developer Ergonomics 13.2 / 20

Access Clarity 6.3 / 20

Operational Transparency 1.0 / 13

Contract Governance 0.5 / 12

Discoverability 7.6 / 10

Agent readiness — 10/100 · agent aware

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 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 Well-Known Document 0 / 5

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

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/prosper: 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 1

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

Prosper Investor API

RESTful API for Prosper investors and third-party agents to view account information, search active loan listings, place orders to purchase Notes, and retrieve owned Notes, inve...

Security Posture 2

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

Prosper Authentication

oauth2 · 3 schemes

SECURITY

Prosper Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

SignUp

Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

WellKnown

WellKnown

LLMsTxt

LLMsTxt

AgentSkill

AgentSkill

Build 1

SDKs, sample code, and the tooling you integrate with

Packages

Packages

Access & Security 3

Authentication, authorization, and security posture

Authentication

Authentication

OAuth

OAuth

DomainSecurity

DomainSecurity

Operate 2

Status, limits, changes, and where to get help

Support

Support

HelpCenter

HelpCenter

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Source (apis.yml)

aid: prosper
name: Prosper
description: Prosper Marketplace operates one of the largest peer-to-peer (marketplace) lending platforms in the United States,
  matching individual and institutional investors with consumers seeking personal loans, and also offering a HELOC and a credit-card
  product. For investors, Prosper publishes a RESTful Investor API that lets individual, institutional, and third-party agents
  connect directly to the platform to view account balances, search active loan listings, place orders (bids) to purchase
  Notes, and track owned Notes, loans, and payments. The API uses OAuth 2.0 over SSL with comprehensive filtering and sorting,
  and offers a sandbox environment for integration testing. This profile was surfaced as a portfolio company of Emergence
  Capital, IVP, and QED Investors and enriched from Prosper's public developer documentation.
url: https://raw.githubusercontent.com/api-evangelist/prosper/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- emergence-capital
- ivp
- qed-investors
x-tier: profiled
x-tier-reason: has-public-api
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
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-20'
image: https://www.prosper.com/favicon.ico
tags:
- Company
- Fintech
- Lending
- Peer-to-Peer Lending
- Marketplace Lending
- Investing
- Personal Loans
- Consumer Credit
- Financial-Services
tags_raw:
- Company
- Fintech
- Lending
- Peer-to-Peer Lending
- Marketplace Lending
- Investing
- Personal Loans
- Consumer Credit
- Financial Services
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
apis:
- name: Prosper Investor API
  description: RESTful API for Prosper investors and third-party agents to view account information, search active loan listings,
    place orders to purchase Notes, and retrieve owned Notes, invested loans, and loan payments. OAuth 2.0 over SSL. Production
    and sandbox environments.
  humanURL: https://developers.prosper.com/docs/investor/
  baseURL: https://api.prosper.com/v1
  tags:
  - Lending
  - Investing
  - Notes
  - Listings
  - Order
  tags_raw:
  - Lending
  - Investing
  - Notes
  - Listings
  - Orders
  properties:
  - type: Documentation
    url: https://developers.prosper.com/docs/investor/
  - type: Authentication
    url: authentication/prosper-authentication.yml
  - type: Conventions
    url: conventions/prosper-conventions.yml
  - type: Idempotency
    url: conventions/prosper-conventions.yml
  - type: ErrorCatalog
    url: errors/prosper-problem-types.yml
  - type: Lifecycle
    url: lifecycle/prosper-lifecycle.yml
  - type: Deprecation
    url: lifecycle/prosper-lifecycle.yml
  - type: Sandbox
    url: sandbox/prosper-sandbox.yml
  - type: X-MCPServerCandidate
    url: mcp/prosper-mcp.yml
    note: 'Renamed from MCPServer 2026-09-03 (roadmap#247): the manifest self-describes as status: candidate — a tool list
      derived from the published API contracts, not an existing server. The scorer already read the manifest and reported
      mcp_server correctly; the MCPServer type was crediting the artifact-type surfaces with a server that does not exist.'
  - type: DataModel
    url: data-model/prosper-data-model.yml
  - type: Conformance
    url: conformance/prosper-conformance.yml
common:
- type: Website
  url: https://www.prosper.com
- type: DeveloperPortal
  url: https://developers.prosper.com/
- type: Documentation
  url: https://developers.prosper.com/docs/
- type: APIReference
  url: https://developers.prosper.com/docs/investor/
- type: GettingStarted
  url: https://developers.prosper.com/docs/investor/
- type: Support
  url: https://developers.prosper.com/support/
- type: HelpCenter
  url: https://help.prosper.com/
- type: Blog
  url: https://www.prosper.com/blog
- type: SignUp
  url: https://www.prosper.com/signup
- type: Pricing
  url: https://www.prosper.com/loans/rates-and-fees
- type: TermsOfService
  url: https://www.prosper.com/legal/terms-of-use
- type: PrivacyPolicy
  url: https://www.prosper.com/legal/privacy-policy
- type: Authentication
  url: authentication/prosper-authentication.yml
- type: OAuth
  url: https://www.prosper.com/oauth
- type: Sandbox
  url: sandbox/prosper-sandbox.yml
- type: DomainSecurity
  url: security/prosper-domain-security.yml
- type: WellKnown
  url: well-known/prosper-well-known.yml
- type: Packages
  url: packages/prosper-packages.yml
- type: LLMsTxt
  url: llms/prosper-llms.txt
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-07-20'
  status: enriched
  artifacts_added: 13
  pass: local-v1

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