ACI Worldwide

ACI Worldwide (NASDAQ: ACIW) is a US-headquartered payment-software company that builds real-time payment, card, merchant/eCommerce, and bill-payment technology for banks, processors, merchants, and billers around the world. Its enterprise portfolio spans BASE24 card and ATM switching, the ACI Enterprise Payments Platform for real-time and ISO 20022 account-to-account rails, and ACI Speedpay bill payment — most of which ship as licensed, on-premise or hosted software rather than public self-serve APIs. ACI's genuinely API-native surface is the ACI Open Payment Platform (the PAY.ON global payment gateway): a unified RESTful API documented at docs.aciworldwide.com that lets merchants and PSPs accept and manage card and alternative-payment transactions through Server-to-Server, COPYandPAY, Mobile SDK, BackOffice, and Pay By Link integrations, authenticated with an Authorization Bearer access token plus a channel entityId and complemented by PAYMENT and REGISTRATION webhook notifications. Its home market is the United States, inside the deep, fragmented, API-native US payments landscape.

ACI Worldwide is listed with 5 APIs on the APIs.io network. Tagged areas include Payments, United States, Payment Gateway, Payment Processing, and Acquiring.

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

ACI Worldwide’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, authentication, changelog, and 20 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

45.7/100 developing ▬ flat Agent 26/100 agent aware Front door AI 5/6 prominent Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

5 APIs 1 MCP Servers

Payments United States Payment Gateway Payment Processing Acquiring Card Payments E-Commerce Fraud Prevention Tokenization 3D Secure Bill Payments Real-Time Payments ISO 20022

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 45.7/100 · developing

Contract Quality 8.3 / 21

Developer Ergonomics 12.1 / 17

Access Clarity 4.9 / 17

Operational Transparency 2.6 / 11

Contract Governance 1.9 / 10

Discoverability 6.5 / 9

Regulatory Posture 5.9 / 15

Agent readiness — 26/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 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 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 5 / 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 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/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
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)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented)
Request/Response Examples +7 pts — share of operations carrying request/response examples; else an Examples / Code Samples link
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document

8 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 39.0 — up to +15.3 composite points
Access Clarity scores 28.9 — up to +14.2 composite points
Operational Transparency scores 23.7 — up to +9.9 composite points

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.

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/aci-worldwide/apis.yml: open an issue on github.com/api-evangelist/aci-worldwide 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
Argentine Fintech Registers (BCRA PSP + entities, CNV agents + PSAV, Cámara Fintech)	standard	47.8	-	-
MACH & Headless Commerce	standard	47.8	-	-

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 3

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.

3-D Secure

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

ISO 20022

tagged — the provider's own APIs.json carries the standard as a tag; implementation not verified

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

APIs 5

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

ACI Open Payment Platform — Server-to-Server API

The core RESTful payment API of the ACI Open Payment Platform (PAY.ON gateway). Server-to-Server integration lets merchants and PSPs run end-to-end payment workflows — preauthor...

ACI COPYandPAY

COPYandPAY is ACI's secure, PCI-friendly embedded payments widget for merchants and integrators. It renders a hosted card and alternative-payment form that tokenizes and submits...

ACI BackOffice API

BackOffice operations on the Open Payment Platform let integrators process and manage previously authorized transactions — captures, refunds, reversals, and related post-authori...

ACI Pay By Link API

Pay By Link lets merchants create secure, customizable hosted payment link pages and collect payments without a full checkout integration, built on the Open Payment Platform gat...

ACI Mobile SDK

The ACI Mobile SDK lets developers accept payments inside native mobile apps, wrapping the Open Payment Platform's card and alternative-payment flows with device-side tokenizati...

MCP Servers 1

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

ACI Worldwide MCP Server

MCP SERVER

Event Specifications 1

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

Aci Worldwide Webhooks

ASYNCAPI

Security Posture 2

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

Aci Worldwide Authentication

http/apiKey · 2 schemes

SECURITY

Aci Worldwide Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Resources

Get Started 3

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Sandbox

Sandbox

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

MCPServer

MCPServer

LLMsTxt

LLMsTxt

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Webhooks

Lifecycle

Components

Conformance

Build 3

SDKs, sample code, and the tooling you integrate with

DeclineCodes

DeclineCodes

Packages

Packages

SDKs

SDKs

Access & Security 3

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Compliance

Compliance

Operate 3

Status, limits, changes, and where to get help

Support

Support

ChangeLog

ChangeLog

ChangeLog

ChangeLog

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 3

The organization behind the API

BlogRSS

BlogRSS

Website

Website

Blog

Blog

Source (apis.yml)

aid: aci-worldwide
url: https://raw.githubusercontent.com/api-evangelist/aci-worldwide/refs/heads/main/apis.yml
name: ACI Worldwide
kind: company
description: 'ACI Worldwide (NASDAQ: ACIW) is a US-headquartered payment-software company that builds real-time payment, card,
  merchant/eCommerce, and bill-payment technology for banks, processors, merchants, and billers around the world. Its enterprise
  portfolio spans BASE24 card and ATM switching, the ACI Enterprise Payments Platform for real-time and ISO 20022 account-to-account
  rails, and ACI Speedpay bill payment — most of which ship as licensed, on-premise or hosted software rather than public
  self-serve APIs. ACI''s genuinely API-native surface is the ACI Open Payment Platform (the PAY.ON global payment gateway):
  a unified RESTful API documented at docs.aciworldwide.com that lets merchants and PSPs accept and manage card and alternative-payment
  transactions through Server-to-Server, COPYandPAY, Mobile SDK, BackOffice, and Pay By Link integrations, authenticated with
  an Authorization Bearer access token plus a channel entityId and complemented by PAYMENT and REGISTRATION webhook notifications.
  Its home market is the United States, inside the deep, fragmented, API-native US payments landscape.'
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: '2026-11-06'
  method: derived
image: https://www.aciworldwide.com/wp-content/uploads/2021/05/cropped-android-chrome-512x512-1-192x192.png
tags:
- Payments
- United States
- Payment Gateway
- Payment Processing
- Acquiring
- Card Payments
- E-Commerce
- Fraud Prevention
- Tokenization
- 3D Secure
- Bill Payments
- Real-Time Payments
- ISO 20022
tags_raw:
- Payments
- United States
- Payment Gateway
- Payment Processing
- Acquiring
- Card Payments
- eCommerce
- Fraud
- Tokenization
- 3D Secure
- Bill Payment
- Real-Time Payments
- ISO 20022
created: '2026-07-24'
modified: '2026-10-06'
specificationVersion: '0.23'
apis:
- aid: aci-worldwide:open-payment-platform-server-to-server
  name: ACI Open Payment Platform — Server-to-Server API
  description: The core RESTful payment API of the ACI Open Payment Platform (PAY.ON gateway). Server-to-Server integration
    lets merchants and PSPs run end-to-end payment workflows — preauthorization, debit, capture, refund, and reversal — across
    cards and alternative payment methods. Requests are authenticated with an Authorization Bearer access token plus a channel
    entityId. Production host is https://eu-prod.oppwa.com and test host is https://eu-test.oppwa.com.
  humanURL: https://docs.aciworldwide.com/integrations/server-to-server
  baseURL: https://eu-prod.oppwa.com
  tags:
  - Payments
  - Server-to-Server
  - Card Payments
  - REST
  tags_raw:
  - Payments
  - Server to Server
  - Card Payments
  - REST
  properties:
  - type: Documentation
    url: https://docs.aciworldwide.com/integrations/server-to-server
  - type: APIReference
    url: https://docs.aciworldwide.com/reference/parameters
  - type: GettingStarted
    url: https://docs.aciworldwide.com/integrations/widget
- aid: aci-worldwide:copyandpay
  name: ACI COPYandPAY
  description: COPYandPAY is ACI's secure, PCI-friendly embedded payments widget for merchants and integrators. It renders
    a hosted card and alternative-payment form that tokenizes and submits sensitive data directly to the Open Payment Platform,
    reducing the merchant's PCI scope while running on the same oppwa.com gateway and access-token/entityId authentication
    as the Server-to-Server API.
  humanURL: https://docs.aciworldwide.com/integrations/widget
  baseURL: https://eu-prod.oppwa.com
  tags:
  - Payments
  - Embedded Checkout
  - PCI
  - E-Commerce
  tags_raw:
  - Payments
  - Embedded Checkout
  - PCI
  - eCommerce
  properties:
  - type: Documentation
    url: https://docs.aciworldwide.com/integrations/widget
  - type: APIReference
    url: https://docs.aciworldwide.com/reference/parameters
  - type: Components
    url: components/aci-worldwide-components.yml
- aid: aci-worldwide:backoffice
  name: ACI BackOffice API
  description: BackOffice operations on the Open Payment Platform let integrators process and manage previously authorized
    transactions — captures, refunds, reversals, and related post-authorization actions — via the same RESTful oppwa.com gateway
    and bearer-token/entityId authentication.
  humanURL: https://docs.aciworldwide.com/integrations/backoffice
  baseURL: https://eu-prod.oppwa.com
  tags:
  - Payments
  - Refunds
  - Transaction Management
  properties:
  - type: Documentation
    url: https://docs.aciworldwide.com/integrations/backoffice
  - type: APIReference
    url: https://docs.aciworldwide.com/reference/parameters
- aid: aci-worldwide:pay-by-link
  name: ACI Pay By Link API
  description: Pay By Link lets merchants create secure, customizable hosted payment link pages and collect payments without
    a full checkout integration, built on the Open Payment Platform gateway.
  humanURL: https://docs.aciworldwide.com/integrations/paybylink
  baseURL: https://eu-prod.oppwa.com
  tags:
  - Payments
  - Payment Links
  - E-Commerce
  tags_raw:
  - Payments
  - Payment Links
  - eCommerce
  properties:
  - type: Documentation
    url: https://docs.aciworldwide.com/integrations/paybylink
  - type: APIReference
    url: https://docs.aciworldwide.com/reference/parameters
- aid: aci-worldwide:mobile-sdk
  name: ACI Mobile SDK
  description: The ACI Mobile SDK lets developers accept payments inside native mobile apps, wrapping the Open Payment Platform's
    card and alternative-payment flows with device-side tokenization and 3-D Secure support against the same oppwa.com gateway.
  humanURL: https://docs.aciworldwide.com/integrations/mobile-sdk
  baseURL: https://eu-prod.oppwa.com
  tags:
  - Payments
  - Mobile SDK
  - In-App Payments
  properties:
  - type: Documentation
    url: https://docs.aciworldwide.com/integrations/mobile-sdk
  - type: APIReference
    url: https://docs.aciworldwide.com/reference/parameters
common:
- url: https://www.aciworldwide.com/feed
  type: BlogRSS
- type: MCPServer
  url: https://docs.aciworldwide.com/integrations/agentic/mcp-server
- type: DomainSecurity
  url: security/aci-worldwide-domain-security.yml
- type: Website
  url: https://www.aciworldwide.com/
- type: DeveloperPortal
  url: https://docs.aciworldwide.com/
- type: Documentation
  url: https://docs.aciworldwide.com/
- type: APIReference
  url: https://docs.aciworldwide.com/reference/parameters
- type: GettingStarted
  url: https://docs.aciworldwide.com/integrations/widget
- type: Support
  url: https://docs.aciworldwide.com/support
- type: Blog
  url: https://www.aciworldwide.com/blog
- type: TermsOfService
  url: https://www.aciworldwide.com/terms-of-use
- type: PrivacyPolicy
  url: https://www.aciworldwide.com/privacy-policy
- type: Authentication
  url: authentication/aci-worldwide-authentication.yml
- type: Conventions
  url: conventions/aci-worldwide-conventions.yml
- type: ErrorCatalog
  url: errors/aci-worldwide-result-codes.yml
- type: DeclineCodes
  url: errors/aci-worldwide-decline-codes.yml
- type: Webhooks
  url: asyncapi/aci-worldwide-webhooks.yml
- type: Lifecycle
  url: lifecycle/aci-worldwide-lifecycle.yml
- type: ChangeLog
  url: https://docs.aciworldwide.com/reference/release-notes
- type: ChangeLog
  url: changelog/aci-worldwide-changelog.yml
- type: Sandbox
  url: sandbox/aci-worldwide-sandbox.yml
- type: Components
  url: components/aci-worldwide-components.yml
- type: Conformance
  url: conformance/aci-worldwide-conformance.yml
- type: Compliance
  url: conformance/aci-worldwide-conformance.yml
- type: Packages
  url: packages/aci-worldwide-packages.yml
- type: SDKs
  url: packages/aci-worldwide-packages.yml
- type: LLMsTxt
  url: llms/aci-worldwide-llms.txt
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

ACI Worldwide API — frequently asked questions

Does ACI Worldwide have an API?

Yes. APIs.io lists 5 APIs from ACI Worldwide, including ACI Open Payment Platform — Server-to-Server API, ACI COPYandPAY and ACI BackOffice API, and 2 more.

How do I authenticate with the ACI Worldwide API?

ACI Worldwide uses bearer-token authentication (http/apiKey · 2 schemes). The details are profiled on APIs.io as Aci Worldwide Authentication.

Does ACI Worldwide have an MCP server?

Yes. APIs.io lists 1 MCP server for ACI Worldwide.

Is the ACI Worldwide API ready for AI agents?

ACI Worldwide has a Kin Score of 45.7 out of 100 (developing) and an Agent Readiness score of 25.8 (agent-aware), scored by API Evangelist on 2026-11-06.

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get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
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resolveTurn a domain, URL or GitHub org into the provider it belongs to.
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Every operation they expose

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How their score was established

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