Self-hosted Excel add-ins

Excel, backed by your data.

Custom Excel functions, defined in a dashboard — served from your own network, never ours.

Quarterly review.xlsx
B2fx=CONNXL.SALES.TOPCUSTOMERS("Q2")
Live · spilled B2:D5 · 96 ms

Works in Excel for Windows, Mac, and the web.

  • Your data never leaves your network
  • mTLS on every agent connection
  • Egress-only — no inbound ports
Private by design

Your data never leaves your network.

The add-in manifest points Excel at an agent you run. Formulas resolve inside your walls — ConnXL stores configuration, never rows.

Excel and your systems talk only to the agent inside your network; only configuration metadata crosses to ConnXL cloud.
ConnXL cloud
Configuration of record
Your network
Excel
=CONNXL. formulas
ConnXL agent
one binary · N replicas
Your systems
Postgres, APIs, more

The only thing that crosses the boundary is configuration metadata. Our backend is never on the path that touches data.

Access you can defend in an audit.

Your identity provider

SSO through Entra ID, Google, or any OIDC provider.

Per-namespace permissions

Allow or deny function namespaces by user or group.

Vault-backed secrets

ConnXL stores a reference. The value never leaves your vault.

mTLS agent channel

Every agent connection is mutually authenticated and encrypted.

Functions

Your own Excel functions. Without writing an add-in.

=CONNXL.SALES.TOPCUSTOMERS("Q2")
=CONNXL.FIN.FX_RATE("EURUSD")1.08421.08471.08391.0844

Streaming functions update the cell as your data moves.

Wrap a query or an endpoint into a named, namespaced function. Version it, promote it across environments, call it from any cell.

16
connector types
11
function kinds — lookups to entities
3
ways to run — sync, async, streaming

Sixteen connector types, one function surface.

  • PostgreSQL
  • MySQL
  • SQL Server
  • Oracle
  • Azure Synapse
  • AWS Athena
  • MongoDB
  • Azure Cosmos DB
  • DynamoDB
  • Valkey / Redis
  • HTTP API
  • GraphQL
  • Files / object storage
  • AWS Lambda
  • Azure Function
  • GCP Cloud Function

Ship an org-wide add-in without writing one.

Describe the add-in. Run the agent. Roll it out.

01

Describe it

Define connections, functions, and your taskpane in the dashboard. No manifest XML, no add-in code, nothing to build.

For the developer
02

Run the agent

One self-contained binary on a machine you control. Bring a TLS certificate — it serves the add-in itself, pulls its config from ConnXL, and scales to N replicas.

For platform & IT
03

Deploy to Excel

Take the generated manifest to the Microsoft 365 admin center and roll the add-in out to the whole organization.

For the M365 admin

End-users just open Excel.

Or build it yourself.

What a hand-rolled Office.js add-in costs you, next to describing it in a dashboard.

Building it yourselfConnXL
Author and version manifest XML and JSON by handGenerated for both formats, always in sync
Build, host, and certify an HTTPS web app for the add-in assetsOne binary serves everything — bring a TLS certificate
Wire up SSO, token exchange, and session handling yourselfEntra ID, Google, or any OIDC provider, built in
Invent your own per-function permissionsAllow or deny namespaces by user or group
Hand-code streaming transports per Excel platformSync, async, and streaming functions out of the box
Re-deploy and re-ingest for every changeConfig changes go live on the next open — no re-deploy
White label

Your name. Your icon. Your taskpane.

What ships looks built in-house.

NNorthwind DataData add-in
Functions
SALES.TOPCUSTOMERSasync
OPS.INVENTORYstreaming
FIN.FX_RATEsync
Signed in with SSO
Pricing

Free for a month. Then $300 per add-in.

Trial

$0 for one month
For testing
1 add-in
Every feature
Unlimited users and replicas

Production

$300/mo per add-in
For everything after
As many add-ins as you need
Flat price — not per seat
Every feature

Questions, answered.

What can ConnXL see?

Configuration metadata only — function definitions, connection settings, telemetry. Formulas resolve inside your network, and our backend is never on the path that touches your data.

Do we need to open inbound firewall ports?

No. The agent dials out to ConnXL over HTTPS to pull configuration — nothing connects in. Excel reaches the agent inside your network, and the agent's only on-disk requirement is a TLS certificate.

What counts as an add-in?

One Excel add-in, with as many environments, functions, connections, and users as you need. Pricing is flat per add-in — never per seat.

What happens when the free month ends?

Your add-in continues on the Production plan. You can cancel at any time from the billing page.

Does it work with our identity provider?

Yes — SSO through Entra ID, Google, or any OIDC provider, with per-namespace allow and deny rules by user or group.

Can we remove the ConnXL branding?

Completely. Set your own name, icon, and taskpane — and choose your own function prefix when you create the add-in, so your users type =NORTHWIND.SALES.TOPCUSTOMERS() instead of =CONNXL…

Which Excel versions are supported?

Excel for Windows, Mac, and the web, rolled out through the Microsoft 365 admin center.

Start with one function.

Connect a source, define a function, type the formula.

Not ready yet? Get product updates.