Groundbreaking innovations that work seamlessly on top of your email provider.

Smart Failover™

What happens when an email fails to go through your provider?

Flute relays and verifies every single outbound email, listens for delivery problems, and automatically takes action by safely rerouting individual emails through a backup provider, whenever possible (without creating duplicates).

We detect certain types of spam bounces, all kinds of API errors, provider downtime, and other sporadic delivery issues.

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Elastic Paper Trails

Search and view all your outgoing email on our dashboard. Yes, the entire email content.

We are the first (and only) delivery platform to offer full-text elastic-searchable logs. We understand the importance of being able to follow-up on your customers, and maintain independent paper trails for auditing and compliance.

Load Balancing

Distribute your email sending volume across multiple providers, in order to gain maximum capacity/cost benefits.

Test and try different providers to compare performance and deliverability, without involving developers.

Secure Isolated Environments

Do you need to send your critical transactional email through Postmark, your marketing email through SendGrid, and highly sensitive email through your own SMTP servers?

Flute makes it easy to segment different types of email through securely isolated environments, with different failover configurations.

Your marketing email reputation, and potential spam complaints, should not affect your critical emails.


Developers will love our simple REST API for sending email and retrieving delivery info, complete with support for attachments and other standard email features.

Alternatively, just drop in our SMTP credentials, and support legacy applications immediately.

View our developer documentation for more info.

Simple Aggregated Statistics

Get a simple, straight answer on how many of your emails were delivered.

We aggregate and simplify the vast myriad of complicated events (bounces, errors, opens, etc.) from multiple providers into one simple data point: SUCCESS or FAIL.

One API for any provider or server

Flute supports Smart Failover and Secure Environments for SendGrid, Mailgun, Amazon SES, SparkPost, Postmark and most SMTP servers.

More providers coming soon!

Let us know if you’d like us to support your provider not listed here.

Always Improving Toolset

Our team enjoys working on email delivery, to the point that it has become an obsession. As a focused, nimble team, we are constantly iterating on our platform, bringing modern features to your delivery API, while monitoring and improving our core reliability and deliverability functions, especially Smart Failover.

Scalable API Infrastructure

Designed to handle the world’s mission-critical email, Flute uses state-of-the art AWS-deployed infrastructure trusted by the world's largest brands. We are bound to our promise to be the most reliable solution for your email, and eventually we plan to build globally redundant availability zones for unparalleled performance and uptime.


Get started in minutes, for free.
Currently in public beta.

For a limited time, contact us and we’ll also check that your SPF, DKIM and DMARC configurations are tuned for maximum deliverability.