Fluidkey

• Name: Fluidkey
• URL: https://www.fluidkey.com/
• Category: privacy-preserving wallet-control plane / stealth-address smart-account wallet
• Tags: ethereum-ecosystem
• Summary: Fluidkey is a privacy wallet built around stealth Safe accounts. The interesting parts are address generation, viewing and spending key derivation, recovery defaults, and the bank-transfer or yield wrappers layered around that wallet surface. The rest is consumer packaging.
• What it does:
  • Uses stealth Safe smart accounts and counterfactual address generation so users can receive funds at privacy-preserving addresses without deploying each account up front
  • Derives user spending and viewing keys client-side from a signed key-generation message, with an open-source kit documenting and implementing the core cryptographic functions
  • Offers self-custodial account recovery through long-term login choice, cloud or local encrypted backups, optional private-key export, and spend-limit / multi-factor controls for larger transfers
  • Provides bank-transfer rails for USD and EUR through Bridge so incoming transfers can settle as USDC into the user’s self-custodial account, with KYC handled through the partner flow
  • Routes supported balances into auto-earn strategies using Morpho and Aave vaults, with the Fluidkey earn module audited by Ackee
  • Adds advanced privacy tooling such as Hide Trail, which uses Houdini Swap private-mode routing plus Fluidkey stealth addresses to reduce onchain linkability
• Key claims:
  • The homepage says Fluidkey has processed more than $740,000,000 in transfer volume and generated more than 1,000,000 privacy-preserving addresses
  • The main docs page describes Fluidkey as a financial home where users can receive, grow, and spend funds with global accounts and instant yield
  • The account-setup docs say Fluidkey is self-custodial, that the app can never touch user funds, and that web keys are generated through a Privy embedded wallet while mobile keys are generated on-device and secured by the secure enclave
  • The technical walkthrough says Fluidkey uses 1/1 Safe smart accounts as stealth accounts, derives stealth signers from a viewing-key node, counterfactually predicts stealth-account addresses, and resolves username.fkey.id / username.fkey.eth to a fresh stealth address on each query
  • The bank-transfer docs say Bridge powers USD and EUR transfers and that incoming transfers are automatically deposited as USDC into a self-custodial Fluidkey account in a privacy-preserving manner
  • The auto-earn docs say the default profile routes balances into selected Morpho and Aave vaults and that the Fluidkey earn module was audited by Ackee
  • The advanced-privacy docs say Hide Trail is powered by Houdini Swap private mode and, when combined with Fluidkey stealth addresses, aims to make funds both untraceable and unlinkable onchain
  • The open-source stealth-account-kit repo says anyone can independently generate and recover stealth smart accounts and related funds
• Whitepaper: No canonical Fluidkey whitepaper or litepaper surfaced in this pass. The clearest current source of truth was the official site, documentation set, privacy policy, technical walkthrough, and open-source stealth-account-kit repository; see ../whitepapers/fluidkey-primary-sources-2026-05-01.md.
• Sources:
  • https://www.fluidkey.com/
  • https://docs.fluidkey.com/
  • https://docs.fluidkey.com/readme/account-set-up
  • https://docs.fluidkey.com/readme/bank
  • https://docs.fluidkey.com/readme/earn
  • https://docs.fluidkey.com/readme/advanced-privacy
  • https://docs.fluidkey.com/technical-documentation/technical-walkthrough
  • https://www.fluidkey.com/privacy
  • https://github.com/fluidkey/fluidkey-stealth-account-kit

Internal linkages

• Core substrate: safe and erc-5564.
• Best control-plane contrast: privy.
• Keep the rest implicit. The yield leg is just downstream routing once funds land.

Control surface

• The leverage sits in stealth-address generation, key-derivation and backup policy, name resolution, partner-routed bank ingress, and the default routing into downstream yield vaults.

• Safe and stealth addressing are the durable substrate. Fluidkey’s actual product power is in the wallet-control layer wrapped around them.

• Read it as privacy-preserving wallet ops with a nicer consumer shell, not as a new protocol rail.

• Last reviewed: 2026-06-18 UTC