A private alternative to Inbox Zero

What to check before you connect Inbox Zero

The permission it asks for

Connecting a Gmail account grants the gmail.modify scope, which covers reading, changing, sending and trashing any message in the mailbox, plus gmail.settings.basic and, where the contacts feature is enabled, your address book. The scope list is in the public source. Klar asks for no permission at all: it is an Apple Mail extension, so macOS hands it the message that is already on your Mac.

Where your mail goes

Its published subprocessor list names six AI model providers: OpenRouter, OpenAI, Anthropic, Google Vertex AI, AWS Bedrock and Groq. Message content is processed by whichever one serves the request, on US infrastructure, with standard contractual clauses for European users. Inbox Zero states that providers may not train on your data and that content is not retained beyond what a feature needs. With Klar the question does not arise: the model runs on your Mac and nothing is sent anywhere.

Which law your mail sits under

Inbox Zero is built in Israel and incorporated as Inbox Zero Inc. in Delaware. Its terms are governed by the law of the State of New York, and its hosting and AI providers are American. For a European user that means message content crosses the Atlantic, covered by standard contractual clauses. Klar is built in France, and the question stops earlier: your mail is classified on your Mac and never transferred, so there is no transfer to put a safeguard around.

Open source is not the same as private

The code is public on GitHub, over 11,000 stars, under AGPL-3.0 with an added clause barring commercial resale, and contributing means signing a CLA governed by Israeli law. Self-hosting it privately is real work: Postgres, Redis, your own Google Cloud OAuth app and Pub/Sub topic, and a machine left on, because mail arrives at all hours. It also means running the model yourself, since pointing the install at a hosted API sends your mail straight back out. In their own example config the hosted providers get frontier models and the Ollama option a 4B one, and closing that gap on your own hardware costs a graphics card, not a config change. Klar needs none of that: deciding whether a message is spam is a classification job, so the model is 382 MB inside the app and runs on a Mac with 8 GB of memory.

What it costs

Starter is $18 per user per month billed annually, which is $216 a year, or $20 month to month. Plus is $28 and Professional $42 on the annual plan. There is a 7-day trial and no free tier. Klar's spam filtering is free, with no account and no subscription.

Where the name comes from

Merlin Mann coined Inbox Zero on 43 Folders in 2006 and explained it in a Google Tech Talk the year after. The zero was never the message count. It was, in his words, “how much of your own brain is in that inbox”, and he has said since that the empty-inbox reading is a misinterpretation. The product is unrelated to him and took the phrase for something else. Worth holding on to when comparing tools: an assistant that sorts and drafts for you still puts your attention in the inbox. A spam filter spends it differently, by making sure the junk was never there to triage.