# Isolated Providers — PostFrame — EternalEngine

Each tenant connects their own email providers with their own API keys and credentials. No shared sending infrastructure between organizations.

[Back to Multi-Tenant](https://eternalengineos.io/features/postframe/multi-tenant/)

Enterprise Architecture

# Isolated Providers

Each workspace connects its own providers with its own credentials, priority order, and daily and hourly limits. A provider failing for one workspace opens a circuit for that connection only.

[Start free](https://app.eternalengineos.io/signup?plan=free&interval=annual)[Multi-tenant overview](https://eternalengineos.io/features/postframe/multi-tenant/)

## Per-Tenant Provider Configuration

Own credentials

Each workspace stores its own SES, Postmark, Mailgun, SendGrid or SMTP credentials — 24 provider adapters in all — never shared

Independent failover

Provider priority and failover rules are configured per-tenant — one tenant's outage doesn't affect others

Per-provider limits

Set a daily and an hourly limit on each connection

Provider mix flexibility

One tenant can use SES, another Postmark — each tenant picks what works for them

Isolation Guarantees

Credentials in the vault

Provider secrets are written to the secrets vault; the database holds only a vault path

Health per connection

An on-demand health check against the provider's API, and a circuit breaker per connection

Rate limits scoped to tenant

Independent throttling per organization

Failover rules configured per-org

Custom fallback chains for each tenant

## Keep exploring PostFrame

[### Bring your own provider Every provider PostFrame connects to, and how failover works. Open Bring your own provider →](https://eternalengineos.io/features/postframe/byop/)[### API key isolation Scoped keys under row-level security. Open API key isolation →](https://eternalengineos.io/features/postframe/multi-tenant/api-key-isolation/)[### Separate domains One workspace per domain, platform-wide. Open Separate domains →](https://eternalengineos.io/features/postframe/multi-tenant/separate-domains/)

Questions

## Common questions, straight answers.

Which providers can a workspace connect?

Amazon SES, Postmark, Mailgun, SendGrid, SparkPost, Brevo, Mailtrap and more — 24 adapters, plus any custom SMTP server. Every connection is private to the workspace that created it.

Where are my provider credentials stored?

In the EternalEngine secrets vault. The PostFrame database keeps only a vault path for each provider connection, never the secret itself.

If another workspace's provider fails, does it affect mine?

No. Circuit breakers are keyed per provider connection, and each workspace has its own connections, so a failing account elsewhere never opens a circuit on yours.

Can I cap how much a provider sends?

Yes. Each connection has optional daily and hourly limits; PostFrame moves to the next provider by priority once a limit is reached.

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