Flowvault - 2026 Pricing, Features, Reviews & Alternatives

Flowvault is a zero-knowledge encrypted notepad application that provides browser-based note taking with client-side encryption and plausible deniability capabilities. The software operates without requiring user accounts or email addresses and positions itself as a privacy-focused alternative to similar solutions. Notes never leave the browser in plaintext and multiple passwords can unlock different notebooks on the same web address. Observers and service operators cannot determine how many notebooks exist or whether any exist at all.

The application employs Argon two-id password hashing with sixty-four mebibytes of memory and three iterations per derivation combined with authenticated encryption using AES-GCM with a two hundred fifty-six-bit key for all stored content. The hidden-volume architecture enables plausible deniability by allowing decoy passwords to unlock separate notebook sets. Each encrypted slot is indistinguishable from random data. Multi-notebook tabs are supported within a single password-protected workspace where tab titles, ordering, and content are encrypted within the same slot. Fixed-size ciphertext prevents analysis of usage patterns and optimistic concurrency control protects against data loss when editing across multiple browser tabs by rejecting stale writes.

A trusted handover feature allows designation of a beneficiary and a check-in interval so that a wrapped key is automatically released to the designated party if the interval elapses. Time-locked notes leverage a distributed randomness beacon to encrypt messages that remain unreadable until a specified future moment. Encrypted send functionality provides self-destructing one-time notes with server-enforced view counts and expiry limits where the decryption key resides in the URL fragment and never reaches the backend.

Bring-your-own-storage mode enables maintenance of vault files entirely on local devices as a single file via the File System Access application programming interface. Encrypted backup and restore capabilities are provided through files that contain opaque ciphertext and key derivation function parameters without embedded passwords. A plaintext Markdown export is available behind explicit confirmation. The application is fully open source with frontend code, cloud functions, security rules, and deployment configuration published in a public repository. Flowvault operates without analytics, third-party scripts, or advertisements and confines browser communications exclusively to its chosen backend. Upgradable key derivation parameters are stored within the vault structure to allow increased computational cost as hardware capabilities evolve without affecting compatibility with existing vaults.