Resolve REST API Custom Integrations: 2026 Developer Guide

Resolve REST API custom integrations are designed for B2B merchants that need net terms, receivables automation, and payment workflows inside a custom stack. If your team runs a proprietary OMS, a custom storefront, an internal procurement workflow, or a non-standard ERP setup, Resolve gives you a flexible way to connect buyer credit decisions, invoicing, collections, and reconciliation without forcing a platform change. Rather than treating credit, payments, and accounts receivable as separate systems, Resolve brings them together in one embedded workflow built for B2B commerce.

That matters because extending terms manually creates two problems at once: slower cash flow for the seller and more operational complexity for the finance team. Resolve is built to address both. It helps merchants offer net terms, automate parts of the credit and receivables lifecycle, accept buyer payments through a branded portal, and connect those workflows to ecommerce, ERP, and accounting systems through native integrations and flexible APIs. For teams outside Resolve’s standard connector set, custom integrations are the path to bringing the same capabilities into an existing environment. This guide explains where custom integrations fit, what to prepare before implementation, how the end-to-end workflow typically works, and which claims you should verify directly in the official developer documentation before going live.

Key Takeaways

• Custom integrations fit non-standard stacks: Resolve’s API approach is best suited to merchants running a proprietary OMS, ERP, marketplace, or storefront that is not already covered by a native connector.
• Resolve combines credit, invoicing, and payments: The platform is built to connect underwriting, receivables workflows, and buyer payment collection in one B2B payments infrastructure.
• Native integrations still matter: If you use a supported platform such as Shopify, NetSuite, or QuickBooks Online, Resolve’s native connectors may reduce custom development work.
• Advance amounts depend on the workflow and risk profile: Resolve supports upfront payment on approved invoices, with advance structures tied to the product and underwriting context.
• Security claims should stay current: Use the official developer docs and current Resolve materials for implementation details, access methods, and security documentation before production rollout.
• The strongest custom builds keep Resolve embedded in core operations: The best implementations connect Resolve to order creation, invoicing, collections, and reconciliation instead of treating it as a separate finance tool.

Why Teams Build Custom Resolve REST API Integrations

Resolve already offers integration options for platforms such as Shopify, BigCommerce, Magento 2, WooCommerce, QuickBooks Online, Xero, NetSuite, and Sage Intacct. If your stack is already supported, that is usually the fastest route to launch.

Custom integrations make sense when your workflow falls outside that list or when your business logic is more complex than a standard connector can handle.

Common use cases for a custom build

• Proprietary OMS or storefront: Your business runs on an internal ordering system or a custom buyer portal.
• Multi-system reconciliation: Orders, invoices, and payment records need to flow across several internal tools.
• Embedded B2B checkout experiences: You want to place Resolve inside your own buyer flow instead of relying only on a standard plugin.
• Marketplace or platform models: You need a credit and payments layer that can connect to a broader product experience.
• Industry-specific workflows: Your invoicing, approval logic, or collections process does not map cleanly to an off-the-shelf integration.

For teams in these categories, Resolve’s integrations platform and B2B net terms infrastructure give you a way to embed credit, payments, and receivables into the systems you already use.

What You Need Before You Start

Before planning a custom Resolve integration, make sure the project is a fit operationally and commercially.

Implementation checklist

1. A Resolve merchant relationship: Your team should already be working with Resolve or be in the process of onboarding.
2. A server-side integration environment: Sensitive credentials and financial workflows should be handled server-side, not in browser code.
3. Clear source-of-truth systems: Decide whether your OMS, ERP, or accounting platform is the authoritative record for customers, orders, invoices, and payment status.
4. A defined receivables workflow: Document how your team currently handles approval, invoicing, reminders, collections, and reconciliation.
5. Technical owners on both sides: Custom integrations move faster when engineering and finance both review the implementation plan.
6. Eligibility alignment: Resolve’s context materials note a minimum of $1M+ annual B2B revenue for eligibility.

If you are still evaluating architecture, review the developer documentation, the integrations overview, and Resolve’s accounts receivable automation product pages first.

How Resolve Custom Integrations Work

At a high level, a custom integration connects four parts of the B2B transaction lifecycle:

1. Buyer qualification and credit assessment
2. Order and invoice workflow
3. Seller funding and buyer payment collection
4. Back-office sync for reconciliation and reporting

Resolve’s product materials consistently position the platform as a system that combines credit, invoicing, collections, and payments in one workflow. That means your integration should be designed around the full order-to-cash process rather than a single API call.

Core workflow

A typical implementation looks like this:

• A buyer requests terms through your custom checkout, sales workflow, or account process
• Resolve evaluates the buyer using its credit and underwriting workflow
• Your system creates or syncs the order and invoice records
• Resolve supports the payment and receivables workflow for approved transactions
• Buyer payments, reconciliation activity, and status changes are reflected back into the systems your team uses

That architecture is why Resolve is often described as an embedded B2B payments platform rather than just a financing tool. The B2B payments platform and accounts receivable automation pages both emphasize reconciliation, invoicing, collections, and payment workflows as part of the same system.

What Data Usually Needs to Sync

The exact field mapping depends on your environment, but most custom integrations need to sync a consistent set of business objects.

Buyer and company data

Your integration may need to pass business identity and account data so Resolve can support credit and workflow decisions. Resolve’s business credit check materials describe streamlined business credit checks and note that only limited business information may be needed in some workflows.

Orders and invoice data

Your system should define how purchase orders, invoice numbers, due dates, payment status, and internal customer IDs map to Resolve. This matters because receivables automation only works cleanly when your order and invoice records are stable and uniquely identifiable.

Payment and reconciliation records

If finance teams still need to manually re-enter buyer payments, funding activity, or status updates, the integration is incomplete. Resolve’s accounts receivable automation and net terms management pages both frame reconciliation and collections as core parts of the product, not optional add-ons.

How Resolve Fits Into Credit and Net Terms Workflows

One reason teams pursue custom integrations is to keep the buyer experience inside their own systems while still using Resolve for net terms and credit workflows.

Credit decisions and underwriting

Resolve positions itself as the merchant’s embedded credit team. Its product materials describe AI-supported underwriting, dynamic credit decisions, and a workflow that combines automated signals with finance-oriented controls. For some credit-check flows, Resolve states that a business name and address may be enough to begin assessment through its business credit check workflow.

Net terms and upfront payment

Resolve’s net terms materials state that sellers can offer terms such as Net 30, Net 45, Net 60, and Net 90, while Resolve helps support cash flow and reduce risk through its non-recourse model. Product pages also note that advance pay can be up to 100% on approved invoices, though the exact structure depends on underwriting, the product used, and the buyer profile.

Collections and buyer payments

Resolve also handles key downstream workflows. Its product materials describe payment reminders, collections support, and branded payment experiences that can accept ACH, wire, credit card, and check depending on the workflow. That is important in a custom integration because your team does not need to rebuild every part of the buyer payment experience from scratch.

Security and Implementation Guardrails

Security language should stay tightly grounded in what Resolve publicly states and in the current developer documentation.

What to keep in scope

• Store credentials in a secure secrets system such as AWS Secrets Manager, Google Secret Manager, or an equivalent internal platform
• Validate message integrity for any callback or signature workflow using standard methods such as HMAC where applicable
• Separate sandbox and production credentials if Resolve provides them in your implementation
• Keep API access server-side
• Confirm production requirements directly in the latest Resolve docs before launch

What not to overstate

Do not publish or document unsupported claims about exact rate limits, authentication schemes, certification status, webhook header names, retry timing, or load-testing allowances unless those details are confirmed in the current official documentation. Resolve’s context materials support the platform’s non-recourse model and embedded workflow, but they do not explicitly verify broad PCI, ISO, or SOC claims in the extracted source set.

Best Practices for a Production-Ready Integration

A strong Resolve integration does more than create records. It makes finance and operations cleaner after launch.

Recommended design principles

• Use one source of truth for invoices: Avoid duplicate invoice creation across your OMS and ERP.
• Store Resolve identifiers with your internal records: This simplifies reconciliation and support.
• Map order states before launch: Decide which events move an order from approved to invoiced to paid.
• Design for exceptions: Credit reviews, invoice corrections, partial shipments, and payment failures should be considered early.
• Keep finance in the loop: Reconciliation rules should be approved by the accounting team before production rollout.
• Review native options first: In some cases, a blend of native integrations and a lighter custom build is the better path.

Resolve REST API vs. Native Integrations

The choice is not always custom build versus no build. Sometimes the better architecture is Resolve’s native connector for a supported system plus custom logic around it.

If your team needs custom buyer experiences but standard accounting sync, a hybrid setup can be especially effective. Resolve’s seller workflows, buyer experience, and net terms for ecommerce pages are useful starting points for planning where custom logic belongs.

Final Verdict: Is a Resolve Custom Integration Right for You?

Resolve custom integrations are the right fit when your team needs to embed net terms, receivables automation, and B2B payments into a stack that does not match Resolve’s native connector model. The value is not just in connecting one endpoint to another. It is in keeping credit, invoicing, collections, and reconciliation inside the same operating workflow.

For B2B merchants that want a more unified order-to-cash process, Resolve offers a stronger foundation than a patchwork of separate credit, payment, and AR tools. Its product suite spans B2B net terms, accounts receivable automation, B2B payments, business credit checks, and flexible integrations. That makes it a practical option for merchants that want to grow sales, get paid faster, and reduce operational friction without pushing buyers into a disconnected finance process.

If you are evaluating a custom build, start with Resolve’s developer docs, map your internal order and invoice lifecycle, and then decide whether a fully custom integration or a hybrid architecture will get you live faster.

Frequently Asked Questions

When should a business choose a custom Resolve integration instead of a native connector?

Choose a custom integration when your team uses a proprietary OMS, a custom storefront, or an internal ERP workflow that is not already covered by Resolve’s native integrations. If your environment is already supported, a native connector may reduce implementation time.

What Resolve products are most relevant to a custom API build?

The most relevant products are Integrations, B2B Net Terms, Accounts Receivable, B2B Payments, and Business Credit Check.

Can Resolve support both buyer-facing and back-office workflows?

Yes. Resolve’s product materials position the platform as supporting buyer credit workflows, invoicing, collections, payment acceptance, and reconciliation, which is why many teams integrate it across both checkout and finance operations.

Does Resolve support non-recourse workflows for approved invoices?

Resolve’s context materials state that cash advances are non-recourse and that sellers can keep approved advances, while Resolve handles underwriting and much of the downstream risk and collections workflow.

Where should developers verify endpoint-level implementation details?

Developers should confirm current implementation details in the official Resolve developer documentation and with the Resolve team before production deployment.

This post is to be used for informational purposes only and does not constitute formal legal, business, or tax advice. Each person should consult his or her own attorney, business advisor, or tax advisor with respect to matters referenced in this post. Resolve assumes no liability for actions taken in reliance upon the information contained herein.