Sieve Studio

no backend

no tracking

no server upload

Sieve filter generator and tester, build email filter rules visually, generate RFC 5228-compliant Sieve scripts and test them against raw messages.
All locally in your browser, compatible with Proton and many others.

Sieve Filter Generator

Build a Sieve filter rule

Add conditions and actions — the Sieve script is generated and updated live as you build.

Rule name Logic for multiple conditions

Conditions

Define when the filter should trigger.

Actions

Choose what should happen when a message matches.

Live Preview

Generated Sieve script

The Sieve script updates instantly as you change the rule.

Supported Proton scope

The generator and tester are aligned with Proton's officially documented list of supported Sieve actions and tests.

Open Proton documentation

Sieve Filter Tester

Test a Sieve filter locally

Paste a Sieve script, load a raw email, and inspect the simulated match result — no server required.

Sieve filter

Email including headers

Paste the full raw message or load a local `.eml` file.

Load local `.eml`

Raw email

Advanced test data

Simulated current time Current flags Envelope-From Envelope-To Current expiration time External lists as JSON