Fluidkey primary sources — 2026-05-01

Project status in this pass

• No canonical standalone whitepaper or litepaper surfaced.
• The clearest current source of truth is the Fluidkey site, docs, privacy policy, technical walkthrough, and the public stealth-account-kit repository.

Primary-source snapshots

1) Main site overview

• URL: https://www.fluidkey.com/
• Key excerpt:
  • 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 page source also links directly to the docs portal, app, recovery site, stealth-account-kit repo, and ecosystem/security references such as Dedaub, Ackee, Bridge, Morpho, Safe, and QuickNode.

2) Main docs landing page

• URL: https://docs.fluidkey.com/
• Key excerpt:
  • The docs landing page describes Fluidkey as a financial home where users can receive, grow, and spend funds with global accounts and instant yield.
  • The navigation also exposes product areas for bank transfers, earn, advanced privacy, recovery, MFA, and a technical walkthrough.

3) Account setup and custody model

• URL: https://docs.fluidkey.com/readme/account-set-up
• Key excerpt:
  • The account-setup page says Fluidkey is self-custodial and that the app can never touch user funds.
  • On web, keys are generated from login via a Privy embedded wallet; on mobile, keys are generated on-device and secured by the secure enclave.
  • Backup options include encrypted cloud backups, local encrypted-file backups, and private-key export.

4) Bank-transfer rails

• URL: https://docs.fluidkey.com/readme/bank
• Key excerpt:
  • The bank docs say users can receive and send USD and EUR transfers from banks, with incoming transfers automatically deposited as USDC into the user’s self-custodial account in a privacy-preserving manner.
  • The feature is powered by Bridge and requires acceptance of partner terms plus KYC during account creation.
  • The docs describe outgoing bank transfers from supported tokens on Base, Ethereum, Arbitrum, and Polygon.

5) Auto-earn layer

• URL: https://docs.fluidkey.com/readme/earn
• Key excerpt:
  • The auto-earn docs say the default Core profile routes balances into selected Morpho and Aave vaults.
  • The page links the Fluidkey earn module audit by Ackee and lists concrete vaults and chains used under the hood.

6) Advanced privacy feature

• URL: https://docs.fluidkey.com/readme/advanced-privacy
• Key excerpt:
  • The advanced-privacy docs say Hide Trail is powered by Houdini Swap private mode, routing funds through two exchanges to remove the link between an existing address and a newly funded one.
  • The page says that combined with Fluidkey stealth addresses, this is meant to make funds both untraceable and unlinkable onchain.

7) Technical walkthrough

• URL: https://docs.fluidkey.com/technical-documentation/technical-walkthrough
• Key excerpt:
  • The walkthrough says users derive private spending and viewing keys from a signed key-generation message and only a BIP-32-derived viewing-key node is shared with Fluidkey.
  • Fluidkey says it uses 1/1 Safe smart accounts as stealth accounts, derives stealth EOAs pseudo-randomly from the viewing-key node, and counterfactually predicts stealth-account addresses so contracts are only deployed when needed.
  • The docs also say username.fkey.id and username.fkey.eth resolve to a new stealth address on every query using an ENS offchain resolver.

8) Privacy policy

• URL: https://www.fluidkey.com/privacy
• Key excerpt:
  • The privacy policy identifies the operator as Fluid Privacy SA in Chiasso, Switzerland.
  • It says Fluidkey does not collect or store KYC/AML information itself, and that if regulated partners require verification, those partners handle it under their own privacy policies and retention schedules.

9) Open-source stealth account kit

• URL: https://github.com/fluidkey/fluidkey-stealth-account-kit
• Key excerpt:
  • The repo says it is an open-source TypeScript library containing the core cryptographic functions used by Fluidkey’s interface and SDK.
  • It says anyone can independently generate and recover stealth smart accounts and related funds.
  • The repo links the technical walkthrough and says the kit was audited by Dedaub in May 2024.

Working conclusion

Fluidkey is best cataloged as privacy-preserving wallet-control-plane infrastructure. The strongest evidence is the combination of stealth-account cryptography, Safe-based smart-account privacy, self-custodial recovery, bank-transfer settlement into self-custodial USDC, yield routing, and optional trail-hiding flows, all documented in first-party docs and reinforced by an open-source crypto kit.