Increase Alternative for Payment APIs | OnlineCheckWriter

Payment API

An Increase Alternative for Teams That Need Payment APIs

Send ACH payments, issue virtual cards, and automate check mailing, all from one payment API.

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OnlineCheckWriter.com – powered by Zil Money, is a financial technology company, not a bank. Banking and money movement services are provided through partner financial institutions and licensed service providers. FDIC insurance coverage applies only to eligible deposit products and accounts, and is subject to applicable terms, conditions, limitations, and requirements. Additional information regarding partner institutions, products, and services is available in the applicable terms and agreements.

One API
payment.json
// One API for ACH, cards, and checks
{
  "method": "ach",
  "amount": "4,250.00",
  "same_day": true,
  "status": "sent"
}
REST API
Sandbox included
PHP · Node.js · Python SDKs
Built for developers

One API for ACH, cards, and checks

Some teams evaluating a banking API platform mainly need to move money: ACH, virtual cards, checks, or multi-method payouts, not build banking infrastructure from scratch.

ACH API

Send ACH credits and debits with one call. Same Day ACH available; your integration team confirms your cutoff during setup. Payment status updates through the API or webhooks.

Virtual Card API

Issue Visa virtual cards for online purchases and vendor payments, with spending limits and card-level controls.

Check Mailing API

Print and mail checks with one call. Pay per check, starting at $1.25 for First Class, no subscription required.

Sandbox & SDKs

Test in a sandbox environment before you go live. Public PHP, Node.js, and Python SDKs are available.

Scope

When OnlineCheckWriter fits, and when it doesn’t

May fit if you need

ACH payments, virtual card issuing, check printing and mailing, or bulk business payments combined in one integration.

A full banking platform may fit better if you need

Direct Federal Reserve network connectivity, or a full end-to-end banking program built from the ground up, such as account issuing, card programs, or a compliance stack.

How it works

Start in three steps

Move one payment method at a time, or all three.

Create a sandbox account

Test ACH, card, or check workflows without moving production traffic.

Map your payment methods

Identify which ACH, check, or card workflows you want to move first.

Move to production

Complete account verification with your integration specialist, then go live.

Built for accounts payable

Everything you need in one payment API

From vendor payouts to payroll, combine payment methods without stitching together separate tools.

  • Bulk Payment API combines ACH, check, wire, and card in one call
  • Batch and recurring ACH payments
  • Role-based permissions for your team
  • Full payment history in your account dashboard
GET/capabilities200 OK
{
  "ach": { "same_day": true },
  "virtual_card": { "issuance": "on_demand" },
  "check_mailing": { "price": "$1.25/check" },
  "bulk_payment_api": {
    "methods": ["ach", "check", "wire", "card"]
  }
}

Same Day ACH requires submitting before your confirmed cutoff time. Per-transaction limit is $1,000,000.

FAQ

Payment API questions, answered

What is OnlineCheckWriter’s ACH API?
A REST API for sending ACH credits and debits programmatically. It supports single, recurring, and batch payments, and is typically used for vendor payments, payroll, and recurring transfers sent directly from an application rather than a banking portal.
Is there a limit on Same Day ACH transactions?
Yes. The current per-transaction limit is $1,000,000, effective since March 2022. This limit comes from the Nacha ACH network rules, not from OnlineCheckWriter specifically. A $10,000,000 cap has been proposed for September 2027 but is not active yet.
Is OnlineCheckWriter Nacha compliant?
Yes. OnlineCheckWriter is an official Nacha member, and the platform holds PCI-DSS and ISO 27001 certifications. Nacha membership means ACH payments sent through the platform follow the same network rules used by standard bank-to-bank ACH transfers.
What happens if an ACH payment is returned?
Return handling depends on the specific return reason, for example insufficient funds or an invalid account number. The exact process is confirmed with the integration team during setup.
How do I create a virtual card?
Virtual cards can be issued through the API or the dashboard, for online purchases and vendor payments. A virtual card is a card number generated for digital use, issued without a physical card.
How does check mailing pricing work?
You pay per check mailed, starting at $1.25 for First Class. There is no subscription fee to use the check mailing feature.
Can I start with only ACH?
Yes. Payment methods can be integrated individually rather than all at once. Production access and migration timing are confirmed with the integration team.
Can I test before migrating anything?
Yes. Sandbox access is available before any production account or verification is required.
Does OnlineCheckWriter replace a direct FedACH connection?
No. OnlineCheckWriter is a payment API built on existing banking rails, not a direct Federal Reserve connection or bank charter.

Start today

See whether your current payment workflow fits

Explore the API, test in sandbox, or talk to an integration specialist.

Get API Access
Book a Demo