In development · onboarding design partners

Your Sage 50 integration, as a CSV as an API.

NexusCortex Connect gives your SaaS product a hosted REST API into each customer's Sage 50 US company file, so bills, expenses and vendors sync instead of being exported, fixed and re-imported.

Become a design partner How it connects

PURCHASES_OCT.CSVToday

Vendor ID,Invoice/CM #,Date,Number of Distributions,G/L Account,Amount

ACME-SUP,10432,10/01/26,1,61000,1250.00

NORTHWIND,88-17,10/01/26,2,6100,310.40

NORTHWIND,88-17,10/01/26,2,64000,89.60

BLUEPINE,A-2291,10/02/26,1,57500,4020.00

HARBOR-LOG,77120,10/02/26,1,57500,615.25

Import stopped at row 3: G/L Account 6100 not found

with NexusCortex Connect

POST /v1/files/cf_8a21/bills

201 Created

{ "id": "bill_31f0", "vendor_id": "NORTHWIND",
  "gl_account": "64000", "status": "posted" }

How it connects

Sage 50 lives on a Windows PC. Your app doesn't have to.

Sage 50 US has no cloud API; its data sits in a company file on the customer's machine. We run a small connector next to it and give your product a normal HTTPS endpoint.

Your product

Your SaaS app

Calls one REST API with an API key

Hosted by us

NexusCortex API

One consistent schema across every customer's file

Customer's PC

Connector

Lightweight Windows service installed alongside Sage 50

Customer's data

Sage 50 company file

Stays exactly where it is today

What your team skips

Ship the integration your customers keep asking for.

If your help center has a “How to import your CSV into Sage 50” article, you already know the support cost.

~~import_template_v7.csv~~

No CSV templates

Push bills and expenses straight into Sage 50, and pull vendors and G/L accounts back to validate before posting.

~~Sage50Sdk.dll~~

No Windows code

The connector, the Sage 50 SDK and yearly version changes are ours to maintain. Your engineers stay in your stack.

~~enterprise_msa.pdf~~

No enterprise contract

Priced per connected company file, so you pay for customers who actually use it.

API preview

Build it once, like any other API.

Familiar REST resources over HTTPS with JSON and API keys. Design partners decide which objects come first.

/vendorsread · create
/accountschart of accounts · read
/billspurchases · create
/invoicessales · create
/paymentsread · create

create-bill.shpreview

# Post a bill to a customer's Sage 50 company file
curl -X POST \
  https://api.nexuscortex.dev/v1/files/cf_8a21/bills \
  -H "Authorization: Bearer $NEXUSCORTEX_KEY" \
  -d '{
    "vendor_id": "ACME-SUP",
    "invoice_number": "10432",
    "date": "2026-10-01",
    "lines": [
      { "gl_account": "61000", "amount": 1250.00,
        "description": "October hosting" }
    ]
  }'

Endpoints and fields may change during the design-partner phase.

Design partners

Help shape the API before it ships.

Free for your first three months of connected company files
We build the objects and endpoints you need first
A direct line to the engineer building it

Apply as a design partner

Or write to admin@nexuscortex.dev

PricingPer company file

Design-partner periodFirst 3 months$0.00

Monthly, per connected fileAfter the design-partner periodSet together

Setup fee or contract minimumNone

Pay only for company files that are connected.