General security warning: Only use hardware wallets to hold your keys / seed phrase and never ever give it away to anybody! You can interface your hardware wallet trough software wallets in order to interact with contract frontends. Do not hold keys in a software wallet, cloud storage, emails, or generally on any device connected to the internet!
Contract address
0x2b591e99afe9f32eaa6214f7b7629768c40eeb39 
Etherscan link
Verified contract code
Contract audits and layman guide
Video tutorial on HEX
Warning: Never send anything directly to the HEX contract address! Always use a contract frontend. HEX sent directly to the contract address cannot be retrieved by anyone.
HEX smart contract frontends
Warnings:
There are plenty of fake frontends that scam users into giving away their keys (seed phrase), or make them sign a malicious withdrawal allowance, or trick them into signing a transfer transaction.
You can verify the authenticity of any frontend by checking the contract address in the wallet transaction dialog box just before you confirm.
If you seek support or advice, only do so in publicly reviewed chat groups – only scammers will contact you privately to offer support (this is a general rule of all decentralized products and social media).
Not all frontends connect to all four networks that currently run the HEX contracts.
go.hex.com: A frontend that works on most wallets and has an abundance of staking data visible; this is the oldest HEX frontend; it can be clunky at times as it loads a lot of data; seek support at @HEXCrypto. Networks:
app.icosa.pro: A frontend for the HEX contract (as well as for Hedron and Icosa 3rd party contracts built on top of HEX). It supports practically all wallet software and Wallet Connect protocol; seek support at @HedronCrypto. Networks: 
backuphex.com: For Metamask and compatible wallets; seek support at @HEXCrypto or contact @Codeak. Networks:
apphex.win: For TrustWallet, CoinbaseWallet, imToken or Metamask, and others via WalletConnect protocol; seek support at @HEXCrypto. Networks:
apphex.win for Ledger: Direct frontend for Ledger Nano S or X that requires no interface software; seek support at @HEXCrypto. Networks:
apphex.win for Trezor: Direct frontend for Trezor that requires no interface software; seek support at @HEXCrypto. Networks:
hexmob.win: For Metamask, including Standalone Metamask, imToken, Coinbase, TrustWallet, and others via WalletConnect protocol; seek support at @HEXCrypto. Networks:
go.tshare.app: For Metamask and others via WalletConnect protocol. It includes the chart of future market supply to aid the staking length optimization; seek support at @HEXCrypto. Networks:
helgo.io: A simplistic frontend for Pulsechain HEX made available by Helgo (a 3rd party hybrid DeFi & meme product for HEX). Works with Metamask, Rabby and most wallets. Networks:
gopulse.com: An easy to use HEX frontend (allows also minting of HDRN). Works with Metamask and most other wallets. Networks:
HEXcrypto: The newest HEX frontend deployed by the Hex Toys team. Its code is free for anyone to deploy on their own website. Networks:
Hexscout: An amazing all in one HEX contract frontend and ecosystem portfolio management tool. Networks:
In the unlikely case that all contract frontends go off-line, here are the instructions on using etherscan.io to interface the HEX contract. Networks:
A local server application is available in a Gitlab repository that lets you run a HEX frontend on the local computer (MacOS, Windows and Linux) and thus be fully independent of external frontends.
Third party products built on top of HEX
The following is not an endorsement for the use of third party products. The selection below is focused on what the community uses and finds useful, further filtered by what is theoretically price positive to HEX. Do your own research and beware of additional attack surface that contracts and products built on top of HEX can represent.
APPs for mobile devices
Hexscout: An amazing all in one HEX contract frontend and ecosystem portfolio management tool. It is available as a website and Android app (soon with an iOS app too). It supports Hedron and Maximus derivatives. Networks:
Hedron and Icosa
Hedron is a third party DAPP that allows the creation of tokenized HEX stakes as bonds (with ERC-721 specifications) and use of these bonds as collateral for borrowing HDRN tokens. Icosa is a third party DAPP that provides continuous and trustless liquidity to sell HEX bonds and particularly suitable for 15 years bonds. The bonds sold to the Icosa contract are then sold on the Hedron contract run auctions.
Hedron: Official website and contract frontend.
Icosa-Hedron: Offical website for staking HEX, HDRN and ICSA. Networks:
HEDRON.today: Hedron HSI auctions frontend. Networks:
HSI Watch: Stake viewer.
Video tutorial on Hedron | Video tutorial on Icosa | Hedron Telegram | Icosa Telegram
Maximus perpetuals
Maximus tokens are DeFi staking derivatives of HEX that are redeemable for yield of trustlessly pooled stakes. There are derivatives for 1 (BASE), 3 (TRIO), 7 (LUCKY), 10 (DECI) or 15 (MAXI) years long stakes. In practice they act as fungible, divisible and liquid HEX bonds (with ERC-20 specifications). The main advantage over direct HEX staking, or over Hedron HEX bonds, is in that the Maximus derivatives occasionally trade at a discount to their NAV value and do not cost you the endstaking network fees which on Ethereum network are a huge hurdle to adoption. They are therefore an excellent alternative to staking small amounts of HEX. The first BASE perpetual completed its first cycle after 1 year without issues, so it appears the contract code functions without flaws.
Maximus perpetuals: Official frontend of BASE (0xe9f84d418B008888A992Ff8c6D22389C2C3504e0), TRIO (0xF55cD1e399e1cc3D95303048897a680be3313308), LUCKY (0x6B0956258fF7bd7645aa35369B55B61b8e6d6140) and DECI (0x6b32022693210cD2Cfc466b9Ac0085DE8fC34eA6). Networks:
Maximus: Official frontend for MAXI (0x0d86EB9f43C57f6FF3BC9E23D8F9d82503f0e84b), which are tokens redeemable for the 15 year pooled stake. Networks:
Video tutorial on Maximus perpetuals | Maximus Telegram
Helgo DAO
The Helgo contract is a Pulsechain HEX/HELGO liquidity farming DeFi contract which uses a market making decentralized autonomous organization (DAO) that allows users to vote on collectively buying or selling HEX on the market using the DAO treasury funds. Overall, this allows HELGO (0x0567CA0dE35606E9C260CC2358404B11DE21DB44) to act as a HEX derivative providing a virtual leverage position on HEX without liquidation risks (at the expense of additional volatility risks). Note that HELGO is a memeFi type of cryptocurrency – it pretends to be nothing more than a memecoin in order to not scare away DeFi sceptics and to attract degen traders, so it has quite some entertaining comedic elements to it.
Helgo: Official Helgo contract frontend. Networks:
HELGO today stats: Website with Helgo contract statistics.
Other third party DAPPs
(Make sure you inform yourself thoroughly on how these APPs and DAPPs work.)
HEXref: Referral system contract for HEX.
HEXnado: Coin anonimizer – fork of the Tornado.cash contract; frontend still rudimentary; note that the anonymity set is still small and fees are currently high; support group @HEXnado.
Cryptocurrency market data aggregators
These data aggregating sites are best for viewing market information about HEX:
TradingView
Mobula
Coinpaprika
Yahoo! finance