Capstack

Capstack Technologies operates a digital bank-to-bank marketplace that lets banks, credit unions, and other financial institutions trade whole loans and loan participations, access liquidity, and manage portfolio concentration risk. Founded in 2023 and headquartered in Miami, FL, the SaaS platform integrates with originating banks' core banking systems and loan-origination systems (LOS) to surface loans available for syndication, then lets participating institutions search by criteria, ask questions live, and submit bids. It adds loan servicing (payment processing, remittance reporting, loan status tracking) and real-time portfolio analytics, specializing in commercial real estate, multifamily residential, and farmland loans. The marketplace has featured over $2B in assets across 200+ registered banks and credit unions. Capstack is backed by Cowboy Ventures and Citi Ventures. This is a private enterprise platform accessed via a demo/onboarding flow; no public developer API, SDKs, or documentation are published at this time.

Capstack is profiled on the APIs.io network. Tagged areas include Company, Fintech, Banking, Loan Marketplace, and Loan Trading.

Capstack’s developer surface includes engineering blog, product news, and 5 more developer resources.

🌐 Visit website 📡 Source on GitHub

9.0/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

0 APIs

CompanyFintechBankingLoan MarketplaceLoan TradingLoan ServicingPortfolio AnalyticsCredit UnionsCapital Markets

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 9.0/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 0.4 / 17

Access Clarity 4.7 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.3 / 9

Regulatory Posture 2.7 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 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

Regulatory Posture applies to this provider. Its tags matched the Banking & Open Finance 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/capstack: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Get Started 1

Portal, sign-up, and the first successful call

Login

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 3

The organization behind the API

Website

Website

Blog

Blog

News

News

Source (apis.yml)

aid: capstack
name: Capstack
description: Capstack Technologies operates a digital bank-to-bank marketplace that lets banks, credit unions, and other financial
  institutions trade whole loans and loan participations, access liquidity, and manage portfolio concentration risk. Founded
  in 2023 and headquartered in Miami, FL, the SaaS platform integrates with originating banks' core banking systems and loan-origination
  systems (LOS) to surface loans available for syndication, then lets participating institutions search by criteria, ask questions
  live, and submit bids. It adds loan servicing (payment processing, remittance reporting, loan status tracking) and real-time
  portfolio analytics, specializing in commercial real estate, multifamily residential, and farmland loans. The marketplace
  has featured over $2B in assets across 200+ registered banks and credit unions. Capstack is backed by Cowboy Ventures and
  Citi Ventures. This is a private enterprise platform accessed via a demo/onboarding flow; no public developer API, SDKs,
  or documentation are published at this time.
url: https://raw.githubusercontent.com/api-evangelist/capstack/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- cowboy-ventures
x-tier: stub
x-tier-reason: portfolio-lead
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://cdn.prod.website-files.com/680e1a1aae58387b8bb8c846/680e204ddfbff60dbb7906ec_capstack-logo.svg
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-18'
tags:
- Company
- Fintech
- Banking
- Loan Marketplace
- Loan Trading
- Loan Servicing
- Portfolio Analytics
- Credit Unions
- Capital Markets
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: DomainSecurity
  url: security/capstack-domain-security.yml
- type: Website
  url: https://capstack.ai
- type: Login
  url: https://app.capstack.ai/
- type: Blog
  url: https://capstack.ai/blog
- type: TermsOfService
  url: https://capstack.ai/terms-conditions
- type: PrivacyPolicy
  url: https://capstack.ai/privacy-policy
- type: News
  url: https://capstack.ai/news
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence