Cardstream

Cardstream is an independent United Kingdom payment gateway providing a white-label payment platform that banks, PSPs, ISOs, acquirers and software companies resell under their own brand. It connects merchants to card schemes (Visa, Mastercard), digital wallets and 150+ Alternative Payment Methods from a single integration, with PCI DSS Level 1 processing, tokenisation, recurring billing, 3-D Secure 2 authentication, risk and fraud checking, and dynamic currency conversion. Its developer surface is a mature form-post gateway API exposed through three integration methods — Hosted (Hosted Payment Pages and Hosted Payment Fields), Direct (server-to-server), and Batch — documented in a public GitBook integration guide and supported by SDKs for PHP, Java, Node.js, Go, Ruby, C#, iOS and Android plus e-commerce modules. Requests are HTTP POST with application/x-www-form-urlencoded fields authenticated by merchantID plus optional password, HMAC message signing and IP allow-listing; the gateway does not publish a downloadable OpenAPI/Swagger definition or a JSON/REST surface.

Cardstream publishes 4 APIs on the APIs.io network. Tagged areas include Payments, United Kingdom, Payment Gateway, Payment Processing, and White Label.

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

Cardstream’s developer surface includes documentation, API reference, getting-started guide, authentication, engineering blog, changelog, sandbox, and 22 more developer resources.

🌐 Visit website 📡 Source on GitHub

50.0/100 developing ▬ flat Agent 26/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

4 APIs

Payments United Kingdom Payment Gateway Payment Processing White Label Card Payments Acquiring Hosted Payment Pages Tokenization 3D Secure Alternative Payment Methods Subscription

Kin Score

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

Composite quality — 50.0/100 · developing

Contract Quality 8.8 / 21

Developer Ergonomics 12.1 / 17

Access Clarity 4.3 / 17

Operational Transparency 4.7 / 11

Contract Governance 1.9 / 10

Discoverability 6.9 / 9

Regulatory Posture 9.4 / 15

Agent readiness — 26/100 · 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 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 6 / 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

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 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.

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/. 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/cardstream: 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 4

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

Cardstream Gateway - Hosted Integration

Hosted Payment Pages (HPP) integration. The merchant's browser POSTs a URL-encoded request to the Gateway, which collects and processes the cardholder's payment details on a Car...

Cardstream Gateway - Direct Integration

Server-to-server integration. The merchant collects payment details on its own secure server and sends a URL-encoded HTTP POST directly to the Gateway for processing, supporting...

Cardstream Gateway - Batch Integration

An enhancement to the Direct Integration that submits multiple transactions in a single multipart/mixed HTTP POST. The Gateway queues the transactions and returns a batch refere...

Cardstream Hosted Payment Fields

A client-side library where only the individual input fields that collect sensitive cardholder data are hosted by the Gateway while the rest of the payment form is served by the...

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Cardstream Webhooks

ASYNCAPI

Security Posture 2

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

Cardstream Authentication

merchantID/password/message-signing/ip-allowlist · 4 schemes

SECURITY

Cardstream Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Get Started 4

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Login

Sandbox

Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions

Idempotency

ErrorCatalog

Conformance

Lifecycle

Components

Webhooks

Scroll for all 7

Build 4

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

SDKs

DeclineCodes

Access & Security 4

Authentication, authorization, and security posture

DomainSecurity

Authentication

Authentication

Compliance

Operate 3

Status, limits, changes, and where to get help

StatusPage

StatusPage

HelpCenter

HelpCenter

ChangeLog

ChangeLog

Commercial 1

Pricing, plans, and the legal terms of use

PrivacyPolicy

PrivacyPolicy

Company 3

The organization behind the API

Website

Website

Blog

Blog

LinkedIn

Source (apis.yml)

aid: cardstream
url: https://raw.githubusercontent.com/api-evangelist/cardstream/refs/heads/main/apis.yml
name: Cardstream
kind: company
description: Cardstream is an independent United Kingdom payment gateway providing a white-label payment platform that banks,
  PSPs, ISOs, acquirers and software companies resell under their own brand. It connects merchants to card schemes (Visa,
  Mastercard), digital wallets and 150+ Alternative Payment Methods from a single integration, with PCI DSS Level 1 processing,
  tokenisation, recurring billing, 3-D Secure 2 authentication, risk and fraud checking, and dynamic currency conversion.
  Its developer surface is a mature form-post gateway API exposed through three integration methods — Hosted (Hosted Payment
  Pages and Hosted Payment Fields), Direct (server-to-server), and Batch — documented in a public GitBook integration guide
  and supported by SDKs for PHP, Java, Node.js, Go, Ruby, C#, iOS and Android plus e-commerce modules. Requests are HTTP POST
  with application/x-www-form-urlencoded fields authenticated by merchantID plus optional password, HMAC message signing and
  IP allow-listing; the gateway does not publish a downloadable OpenAPI/Swagger definition or a JSON/REST surface.
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: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - authentication
  - security
  - sandbox
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
tags:
- Payments
- United Kingdom
- Payment Gateway
- Payment Processing
- White Label
- Card Payments
- Acquiring
- Hosted Payment Pages
- Tokenization
- 3D Secure
- Alternative Payment Methods
- Subscription
tags_raw:
- Payments
- United Kingdom
- Payment Gateway
- Payment Processing
- White Label
- Card Payments
- Acquiring
- Hosted Payment Pages
- Tokenization
- 3-D Secure
- Alternative Payment Methods
- Subscriptions
created: '2026-07-24'
modified: '2026-07-24'
specificationVersion: '0.23'
apis:
- aid: cardstream:cardstream-gateway-hosted
  name: Cardstream Gateway - Hosted Integration
  description: Hosted Payment Pages (HPP) integration. The merchant's browser POSTs a URL-encoded request to the Gateway,
    which collects and processes the cardholder's payment details on a Cardstream-hosted page (lightbox, redirect or iframe)
    and POSTs the signed result back to the merchant's redirectURL. Removes cardholder data from the merchant's PCI scope.
  humanURL: https://guides.gitbook.io/integrationguide/getting-started/introduction-to-our-gateway/integration-methods
  baseURL: https://gateway.cardstream.com/hosted/
  tags:
  - Hosted Payment Pages
  - Card Payments
  properties:
  - type: Documentation
    url: https://guides.gitbook.io/integrationguide/
  - type: APIReference
    url: https://guides.gitbook.io/integrationguide/gateway-functionality/features/new-transactions/request-fields
- aid: cardstream:cardstream-gateway-direct
  name: Cardstream Gateway - Direct Integration
  description: Server-to-server integration. The merchant collects payment details on its own secure server and sends a URL-encoded
    HTTP POST directly to the Gateway for processing, supporting sales, refunds, cancellations, 3-D Secure 2, tokenisation
    and management requests. Optionally used with Hosted Payment Fields so sensitive card data is tokenised by the Gateway
    before the Direct request.
  humanURL: https://guides.gitbook.io/integrationguide/getting-started/introduction-to-our-gateway/integration-methods
  baseURL: https://gateway.cardstream.com/direct/
  tags:
  - Card Payments
  - Refunds
  - 3D Secure
  - Tokenization
  tags_raw:
  - Card Payments
  - Refunds
  - 3-D Secure
  - Tokenization
  properties:
  - type: Documentation
    url: https://guides.gitbook.io/integrationguide/
  - type: APIReference
    url: https://guides.gitbook.io/integrationguide/gateway-functionality/features/new-transactions/request-fields
  - type: Authentication
    url: https://guides.gitbook.io/integrationguide/getting-started/setting-up-your-integration/authentication
- aid: cardstream:cardstream-gateway-batch
  name: Cardstream Gateway - Batch Integration
  description: An enhancement to the Direct Integration that submits multiple transactions in a single multipart/mixed HTTP
    POST. The Gateway queues the transactions and returns a batch reference number used to download a status file; useful
    for capturing many transactions or collecting recurring subscription and loan-repayment charges. Does not support interactive
    flows such as 3-D Secure or wallet checkouts.
  humanURL: https://guides.gitbook.io/integrationguide/getting-started/introduction-to-our-gateway/integration-methods
  baseURL: https://gateway.cardstream.com/direct/
  tags:
  - Batch
  - Subscription
  - Recurring
  tags_raw:
  - Batch
  - Subscriptions
  - Recurring
  properties:
  - type: Documentation
    url: https://guides.gitbook.io/integrationguide/
  - type: APIReference
    url: https://guides.gitbook.io/integrationguide/getting-started/setting-up-your-integration/integration-details
- aid: cardstream:cardstream-hosted-payment-fields
  name: Cardstream Hosted Payment Fields
  description: A client-side library where only the individual input fields that collect sensitive cardholder data are hosted
    by the Gateway while the rest of the payment form is served by the merchant. On submission the Gateway returns a payment
    token representing the card data, which the merchant then processes via the Direct Integration without ever handling raw
    cardholder data.
  humanURL: https://guides.gitbook.io/integrationguide/references/code-references/integration-libraries/hosted-payment-fields-library
  baseURL: https://gateway.cardstream.com/hosted/
  tags:
  - Tokenization
  - Hosted Payment Pages
  properties:
  - type: Documentation
    url: https://guides.gitbook.io/integrationguide/references/code-references/integration-libraries/hosted-payment-fields-library
common:
- type: DomainSecurity
  url: security/cardstream-domain-security.yml
- type: Website
  url: https://cardstream.com/
- type: DeveloperPortal
  url: https://cardstream.com/developer/
- type: Documentation
  url: https://guides.gitbook.io/integrationguide/
- type: APIReference
  url: https://guides.gitbook.io/integrationguide/gateway-functionality/features/new-transactions/request-fields
- type: GettingStarted
  url: https://guides.gitbook.io/integrationguide/getting-started/setting-up-your-integration
- type: Authentication
  url: https://guides.gitbook.io/integrationguide/getting-started/setting-up-your-integration/authentication
- type: GitHubOrganization
  url: https://github.com/cardstream
- type: StatusPage
  url: https://status.cardstream.com/
- type: HelpCenter
  url: https://support.cardstream.com/hc/
- type: Login
  url: https://mms.cardstream.com/
- type: Blog
  url: https://cardstream.com/blog/
- type: PrivacyPolicy
  url: https://cardstream.com/privacy-policy/
- type: LinkedIn
  url: https://www.linkedin.com/company/cardstream
- type: Packages
  url: packages/cardstream-packages.yml
- type: SDKs
  url: packages/cardstream-packages.yml
- type: Authentication
  url: authentication/cardstream-authentication.yml
- type: Conventions
  url: conventions/cardstream-conventions.yml
- type: Idempotency
  url: conventions/cardstream-conventions.yml
- type: ErrorCatalog
  url: errors/cardstream-problem-types.yml
- type: DeclineCodes
  url: errors/cardstream-decline-codes.yml
- type: Conformance
  url: conformance/cardstream-conformance.yml
- type: Compliance
  url: https://guides.gitbook.io/integrationguide/getting-started/introduction-to-our-gateway/security-and-compliance
- type: Lifecycle
  url: lifecycle/cardstream-lifecycle.yml
- type: ChangeLog
  url: changelog/cardstream-changelog.yml
- type: Sandbox
  url: sandbox/cardstream-sandbox.yml
- type: Components
  url: components/cardstream-components.yml
- type: Webhooks
  url: asyncapi/cardstream-webhooks.yml
- type: LLMsTxt
  url: llms/cardstream-llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

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