Synctera Alternative for Payment APIs | OnlineCheckWriter

Payment API

A Synctera Alternative for Teams That Need Payment APIs

Add ACH payments, virtual cards, and check mailing to your product, without building a full banking program from the ground up.

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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
embed.json
// Add payment features to your product
{
  "method": "virtual_card",
  "amount": "850.00",
  "purpose": "vendor_expense",
  "status": "issued"
}
REST API
Sandbox included
PHP · Node.js · Python SDKs

Illustrative example. See the API docs for exact request format.

Add payments without a full BaaS build

What OnlineCheckWriter covers

Some teams building a product don’t need to launch a full banking program, they need to add ACH, virtual cards, or check mailing to what they’ve already built. OnlineCheckWriter covers that narrower need.

ACH API

Add ACH transfers to your product with one call. Same Day ACH available; your integration team confirms your cutoff. Payment status updates through the API or webhooks.

Virtual Card API

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

Check Mailing API

Add check mailing to your product 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

What this does and doesn’t replace

May fit if you need

ACH payments, virtual card issuing, check mailing, or bulk payments added to your existing product.

A full banking platform may fit better if you need

Customer account or card-program issuing, KYC/KYB and compliance monitoring, or ledger infrastructure built for an embedded-finance program.

Adding payments

Add payment features in three steps

Start with the feature your product needs most.

Create a sandbox account

Test ACH, card, or check calls against your own product flow.

Pick your first feature

Most teams start with virtual cards or ACH, then add check mailing later.

Go live with your integration specialist

Complete verification and move from sandbox to production when you’re ready.

Modular by design

Add only the payment features you need

No requirement to adopt a full banking, compliance, or ledger stack to use one payment feature.

  • Bulk Payment API combines ACH, check, wire, and card in one call
  • One-time-use virtual cards for single transactions
  • 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"]
  }
}
FAQ

Payment API questions, answered

ACH

What is OnlineCheckWriter’s ACH API?
A REST API for sending ACH credits and debits programmatically. It supports single, recurring, and batch payments.
Is there a limit on Same Day ACH transactions?
The Nacha ACH network sets a $1,000,000 per-transaction ceiling for Same Day ACH, effective since March 2022. Your specific account limit is confirmed with your integration team and may be lower than the network ceiling. A $10,000,000 network ceiling has been proposed for September 2027; it is not in effect yet.

Virtual Cards

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.

Check Mailing

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.

Account & Security

Is OnlineCheckWriter Nacha compliant?
Yes. OnlineCheckWriter is an official Nacha member, and the platform holds PCI-DSS and ISO 27001 certifications.
Does OnlineCheckWriter provide KYC/KYB or compliance monitoring for my platform?
No. OnlineCheckWriter is a payment API for ACH, virtual cards, and check mailing. It does not offer KYC/KYB onboarding or compliance/risk monitoring tooling. Your platform remains responsible for its own KYC/KYB and compliance program.

Adding to Your Product

Can I add just one payment feature without building the others?
Yes. Payment methods can be integrated individually rather than all at once. Production access and timing are confirmed with the integration team.
Can I test before integrating into my product?
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.

Add it in

See if these payment features fit your product

Test ACH, virtual cards, or check mailing in sandbox, or talk to an integration specialist.

Get API Access
Book a Demo