---
title: "open connection · RUAL Documentation"
description: "Opens an mssgs mail connection for the send blocks. Leave both pins empty to use the mssgs mail service provider this entity binds to transactional emai…"
canonical: https://docs.rual.nl/block-types/mssgs%20mail/mssgsmailconnection_open
language: en
---

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# open connection

This block is part of the [`mssgs mail`](https://docs.rual.nl/block-types/mssgs%20mail) group and was last modified in core [`v15.0.1`](https://docs.rual.nl/core-versions/150001).

Opens an mssgs mail connection for the send blocks. Leave both pins empty to use the mssgs mail service provider this entity binds to transactional email; name a `provider` to use a specific one; or pass a literal API key on `api key`.

- flow `flow`

- provider `value` Name of an mssgs mail service provider (Settings → Service providers). Empty uses the one bound to transactional email.

- api key `value` A literal `msm_…` API key. Only read when `provider` is empty. Stored in the blueprint in plaintext : a service provider is the better home for it.

- flow `flow`

- success `condition`

- error `value`

- connection `mssgsmailconnection`

Builds the connection object every mssgsmailconnection_* block takes. Makes NO network call. Credential order: `provider` (the name of an mssgs mail service provider) → with `provider` empty, a literal `token` (an msm_… API key) → with both empty, the mssgs mail provider the entity binds to the transactional_email purpose. A provider-based connection carries only the provider NAME; the key is resolved at send time and never appears on a pin or in a simulation trace. A literal token IS stored in the blueprint in plaintext : prefer a provider. success=false with error PROVIDER_WRONG_TYPE when the named or bound provider is Postmark/Lettermint rather than mssgs mail, PROVIDER_NOT_FOUND for an unknown name, NO_CREDENTIAL when nothing resolves. Branch on success before sending.

| `mssgsmail` |
| --- |
| `mssgs mail` |
| `email` |
| `mail` |

A typical wiring for [open connection](https://docs.rual.nl/block-types/mssgs%2520mail/mssgsmailconnection_open): a [function trigger](https://docs.rual.nl/block-types/globals/trigger_custom_function) starts the flow; the `flow` out pin feeds [debug](https://docs.rual.nl/block-types/state%2520ui/state_debug).

[![Studio canvas example for the open connection block: typical wiring for open connection.](https://docs.rual.nl/canvas-examples/mssgsmailconnection_open.png)](https://docs.rual.nl/canvas-examples/mssgsmailconnection_open.png?v=3)

## Version history

Introduced in [`v15.0.1`](https://docs.rual.nl/core-versions/150001).

- [Back to `mssgs mail`](https://docs.rual.nl/block-types/mssgs%20mail): Return to the main group to view all sub-groups

- [Back to `mssgs mail`](https://docs.rual.nl/block-types/mssgs%20mail?group=mssgs%20mail): Return to the group to view all blocks within this group

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