Newline Transfers API
Initiate, list, retrieve, and cancel Transfers that move assets between Synthetic Accounts across payment rails — ACH, wire, Real-Time Payments (RTP), and internal book transfers. Balance and access checks run before a Transfer is initiated, and Transfers can be canceled only while queued or pending. This is the core money-movement endpoint of the Newline platform.
Newline Transfers API is one of 13 APIs that Fifth Third Bancorp publishes on the APIs.io network, described by a machine-readable OpenAPI specification.
Tagged areas include Transfers, Payments, ACH, Wire, and Real-Time Payments. The published artifact set on APIs.io includes an OpenAPI specification, an API reference, and API documentation.
This API exposes 53 operations across 40 paths, organized into 13 resource areas. It is described by OpenAPI 3.0.2, at version 1.0.0.
Requests are made against a single base URL, https://sandbox.newline53.com/api/v1.
Metadata
The identity and technical contract details declared by the specification.
Authentication & Security 1
Newline Transfers API declares
1 security scheme
for authenticating requests.
An API key is passed in the header as Authorization (ApiKeyAuth).
By default, every request must be authenticated.
ApiKeyAuth— Access token signed with shared HMAC
Paths & Operations 53
Across 40 paths, the API surfaces 53 operations — 3 DELETE, 34 GET, 9 POST, 7 PUT. They span 13 resource areas, including Auth, Customers, Pools, Products, Customer Products, Custodial Accounts, Synthetic Accounts, Transfers, and 5 more. Each is listed below with its method, path, parameters, and response codes.
The Authentication section explains how to securely interact with Newline's API using access tokens and static IP addresses. Learn how to generate and refresh tokens to access pro…
The Customers section provides details on managing end-user accounts. Learn how to create, update, and archive customer records and onboard them to financial products while meetin…
Pools group multiple Customers for asset sharing and distributed account ownership. Each Pool is unique to a Customer or program. Endpoints: - GET [List Pools: GET /pools](https:/…
Products represent financial services available in your program. Discover onboarding requirements, prerequisites, and detailed product configurations. Endpoints: - GET [List Produ…
Customer Products link Customers to financial products. This section outlines how to onboard customers, manage their product relationships, and track statuses. Endpoints: - GET [L…
Fifth Third Bank holds Custodial Accounts and represents funds managed for Customers. Through these endpoints, you can manage balances and track account statuses. Endpoints: - GET…
Synthetic Accounts serve as the foundation for asset tracking in Newline. They allow for flexible configurations tailored to your program. Endpoints: - GET [List Synthetic Account…
Transfers facilitate the movement of assets between accounts, enabling transactions such as payments and withdrawals. Endpoints: - GET [List Transfers: GET /transfers](https://dev…
The Sandbox section provides tools to test and simulate interactions with the Newline API in a controlled environment. Endpoints: - POST [Simulate a Transaction: POST /sandbox/moc…
Transactions represent asset movements, such as ACH payments, wire transfers, or card purchases. Track transaction statuses and events through these endpoints. Endpoints: - GET [L…
VRNs act as aliases for accounts, enabling unique use cases like accounts receivable segmentation or reconciliation. Endpoints: - GET [List Virtual Reference Numbers: GET /virtual…
The Returns endpoints help initiate, track, and manage returns of received and originated payments. These endpoints are accessible within the Sandbox and Production environments.…
The Combined Transfers endpoint allows clients to create both a transfer and a counterparty in a single API call. This simplifies the process by eliminating the need to first crea…
Specification
The full machine-readable OpenAPI contract behind this narrative.
Source
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Other APIs Fifth Third Bancorp publishes across the network.