How to use this page
Every entry below starts with a one line definition, so you can usually stop there. Where a term has a full guide on this hub, the entry links to it, and the guide carries the sources and the dates. For live data, the block explorer, the validators page and NimMap are all on this site. The terms are alphabetical.
A
Account
A Nimiq account is a key, and the addresses derived from it, which is the thing that owns NIM.
There is no login and no record on a server. A key pair is generated on your device, and a basic account comes into existence on chain when NIM is first sent to its address. An account can also be a Ledger hardware wallet. How it is made, and what holds the key, is in how to create a Nimiq wallet.
Active and inactive stake
Active stake is the part of your stake that is delegated and counting toward your validator; inactive stake has been deactivated and is serving out the lock period.
Only the active balance earns. Deactivating moves value from active to inactive, where it earns nothing while it cools down, then to retired, then out. The three buckets are walked in how to unstake NIM.
Albatross
Albatross is Nimiq's proof of stake consensus protocol, which replaced proof of work on 19 November 2024.
Under Albatross, validators stake NIM as a deposit and take turns producing blocks, rather than miners competing on hardware. It is a Byzantine fault tolerant design, and it is not a hybrid of proof of work and proof of stake. The full mechanism is in how Albatross works.
Address (NQ...)
A Nimiq address is the public identifier of an account, printed in blocks of four characters and starting with NQ.
Addresses start with NQ and are written in groups of four, which makes them far easier to check by eye than an unbroken string. Anyone can look up an address and see its transactions, because the ledger is public. What an address is, and where one comes from, is in what is Nimiq.
B
Batch
A batch is a run of 60 blocks, 59 micro and one macro, closed by the macro block where finality happens.
At about one block per second a batch lasts about a minute. The macro block that closes it is where a transaction becomes final. 720 batches make an epoch. Reading a batch on the live chain is covered in reading the Nimiq chain.
Block, micro and macro
A micro block carries user transactions and is produced by one validator; a macro block closes a batch and is agreed by a supermajority vote.
Micro blocks arrive about a second apart. The macro block that closes each batch carries no user transactions, only the reward, and it is where finality happens. The distinction is the heart of how Albatross works.
C
Checkpoint
A checkpoint block is a macro block that closes a batch and keeps the same validator set, without electing a new one.
Most macro blocks are checkpoints. The one that closes the last batch of an epoch is an election block instead, which changes the validator set. There are 719 checkpoints and one election in each epoch. See reading the Nimiq chain.
Cold key
The cold key is the validator address key, derived from which the validator's address cannot be changed, and kept offline.
A Nimiq validator uses four keys: the cold validator address key, a signing key, a voting key and a reward address. The cold key is the one with no recovery path and the one you can never afford to lose. The full set is in how to run a Nimiq validator.
D
Deactivate
Deactivating is the first step of unstaking, moving part or all of your stake from active to inactive and starting the lock.
It takes effect at the next election block, and the inactive balance then serves out a lock of one epoch before it can be retired. Deactivating is not withdrawing. The sequence is in how to unstake NIM.
Delegation
Delegation is the on chain act of naming a validator to back, with your NIM staying under your own key in the staking contract.
Staking on Nimiq is delegation: you send one transaction that records you as a staker and names a validator, and from then on your NIM counts toward that validator's total stake. Only your own address can undo it. The walkthrough is in how to stake NIM.
Direct payout
A direct payout is a validator's declared method of sending your share of rewards to your address as an ordinary transfer.
Distribution to stakers happens off chain, under the validator's own policy. A direct payout sends NIM to you, where a restake adds it to your delegated balance instead. The two are compared in where rewards come from.
E
Election block
The election block is the macro block that closes the last batch of an epoch and chooses the validator set for the next one.
It hands out 512 slots in proportion to stake. After it, the set of validators producing blocks changes, which is how you can tell an epoch has ended. Election and the epoch are covered in reading the Nimiq chain.
Epoch
An epoch is a run of 720 batches, so 43,200 blocks, about 12 hours, closed by an election block.
The validator set does not change inside an epoch, and stake changes only take effect at the next election block. Some documentation says 1440 batches per epoch, which contradicts the 12 hour figure and does not match a node's numbers; this site uses 720. See reading the Nimiq chain.
F
Finality
Finality is the point at which a transaction is settled and the protocol will not reverse it, reached at the macro block that closes its batch.
On Nimiq the macro block vote is the settlement itself, not a probability. Once it lands the batch is final. That is different from Bitcoin, which never finalises absolutely. The comparison is in how Albatross works.
H
Hub
The Hub is the doorway at hub.nimiq.com that other websites use to ask your wallet for a signature.
It does not hold keys. It routes requests from a requesting application to Keyguard, which holds the keys and signs. The developer documentation treats the requesting app as untrusted, the Hub as semi trusted, and Keyguard as the only fully trusted piece. The trust boundary is in how to create a Nimiq wallet.
J
Jail
Jailing is the protocol's response to serious misbehaviour such as equivocation: the validator is locked out for eight epochs with its rewards burned.
A jailed validator cannot be re-elected while jailed, though it must still vote until the current epoch ends. Its stakers cannot release funds until the jail ends. Punishments, including jailing, are covered in how to run a Nimiq validator.
K
Keyguard
Keyguard is the component that stores your private keys and signs with them, on its own isolated origin, so no page can read them.
Keyguard never hands a key to the page that asked for a signature, and even a backup export runs inside it so the calling app never receives recovery words. It is the only fully trusted component in the browser design. It is explained in how to create a Nimiq wallet.
L
Luna
The luna is the smallest unit of NIM, at 100,000 luna to one NIM, the way a satoshi is the smallest unit of bitcoin.
Almost every raw number in the protocol is in luna, which is why an unconverted balance looks a hundred thousand times too large. Validator deposits, minimum stakes and RPC amounts are all luna. The unit is explained in NIM tokenomics.
M
Mini app
A mini app is a web application that runs inside Nimiq Pay and can ask the wallet for things such as an address, a signature or a payment.
The wallet keeps custody throughout, and every sensitive request surfaces as a native dialog the mini app cannot bypass. The SDK exposes exactly ten wallet methods. The model, the methods and how to judge one are in mini apps in Nimiq Pay.
N
NIM
NIM is the native coin of the Nimiq blockchain, used for fees and for staking, with a maximum supply of 21 billion.
It is not a token on another chain. NIM pays transaction fees, is what you stake, and its smallest unit is the luna. What NIM is and how it works is in what is Nimiq.
Nimiq Pay
Nimiq Pay is the self custodial mobile payments app published by Nimiq Labs, which also hosts mini apps.
It is an interface over a key that sits on your device, so nobody can freeze, spend or restore the account for you. It opens the same account you can use at wallet.nimiq.com. The app is explained in Nimiq Pay explained.
P
Payout schedule
A payout schedule is the interval at which a validator that pays directly sends your share of rewards to your address.
It belongs to the direct payout type, as a cron field stating how often NIM will be sent. A restake validator has no send to schedule. Reading a blank schedule field is covered in choosing a Nimiq validator.
Penalty
A penalty is a punishment the protocol applies for misbehaviour, in the form of burned rewards and lost eligibility rather than confiscated principal.
A missed block burns the reward for that slot. Equivocation jails the validator for eight epochs with rewards burned. In neither case is delegated NIM confiscated. Penalties are covered in how to run a Nimiq validator.
Proof of stake
Proof of stake is the consensus design where validators lock NIM as a deposit and take turns producing blocks, instead of miners competing on hardware.
Nimiq moved to proof of stake on 19 November 2024 with the Albatross protocol. Stake decides how much work a validator gets, and the protocol punishes the ones that misbehave. It is the subject of how Albatross works.
R
Restake
Restaking is a validator's declared method of adding your share of rewards to your delegated balance, so it compounds, instead of sending it to you.
It happens off chain in the distribution step, and the validators list states which method an operator uses. A restaking validator makes your staker balance grow; a direct one leaves it flat and sends transfers instead. See where rewards come from.
Retire
Retiring is the second step of unstaking, moving the released inactive balance into the retired bucket that the withdrawal can draw from.
It is only accepted once the lock has passed, and it is the step with the clock on it. For a staker whose validator is not jailed, the lock is one epoch counted from the next election block. The full sequence is in how to unstake NIM.
Reward
A staking reward is newly issued NIM plus the transaction fees in a batch, paid to the validator's reward address and passed to stakers off chain.
The protocol pays the whole batch reward to the validator, not to stakers directly, and the split happens under the validator's own policy. There is no rate printed here, because rates move with everything staked. The mechanism is in where rewards come from.
S
Self-stake
Self-stake is a validator's own deposit, which is the part of its total stake that is not delegated to it by anyone else.
A validator can only hold the deposit as its own stake; everything above that has to arrive as delegation. A validator with only its deposit behind it is a small fraction of one slot. See how to run a Nimiq validator.
Signal data
Signal data is a field in the validator record, used for chain upgrades and coordination such as signalling readiness for a protocol change.
The field is part of the on chain validator record, and reading it shows validators actively coordinating rather than a dormant network. It is described in is Nimiq still active.
Skip block
A skip block is a canonical empty block produced by the remaining validators when the expected producer misses its turn.
It carries no transactions, inherits the previous random seed, timestamps itself four seconds after the previous block, and needs a supermajority of signatures. It is how the chain moves on without waiting. See how Albatross works.
Slot
A slot is one of the 512 positions handed out to validators at each election block, in proportion to stake, and held for the whole epoch.
The batch reward is spread evenly across slots, so more slots mean a larger share. A validator with no slots in an epoch produces nothing and earns nothing. Slots are covered in how Albatross works.
Staker
A staker is an address that has delegated NIM to a validator, recording its delegation on the staking contract.
A staker record holds one delegation field, so an address backs one validator at a time. A staker's NIM stays under its own key, and only that address can unstake it. How to become one is in how to stake NIM.
T
Tombstone
A tombstone is a record the protocol leaves after a validator is deleted, so stakers who still have stake behind it can withdraw it.
Deleting a validator only completes once its delegations are out, but if stake remains the chain leaves a tombstone so those stakers can still get their NIM out. It protects stakers at the cost of time rather than principal. See how to run a Nimiq validator.
V
Validator
A validator is a registered node that locks a 100,000 NIM deposit and produces blocks for the slots it is elected to.
Registered, active and elected are three different states, and only the last one produces blocks. A validator's fee is a policy it publishes off chain, not a protocol field. Running one is covered in how to run a Nimiq validator.
Validator fee
A validator fee is the operator's cut of the rewards it distributes to its stakers, taken off chain after the protocol has paid the batch reward.
There is no fee field in a Nimiq validator record, so no fee is enforced by consensus. A fee is a published policy, and a lower fee matters only out of rewards that exist. Reading fees is the subject of choosing a Nimiq validator.
Vesting contract
A vesting contract is one of Nimiq's fixed account types, which releases a balance on a schedule.
Alongside basic accounts, hashed time locked contracts and the staking contract, vesting is one of exactly four account types on the chain. It releases a balance on a schedule. The account model is described in the comparison with Bitcoin and Ethereum.
W
Warm and signing key
The signing key, a warm key that lives on the running node, signs the micro blocks a validator produces.
Unlike the cold validator address key, the signing key sits on the node so it can sign in real time, and so does the voting key that participates in consensus. Losing or leaking the warm keys is the classic way to equivocate by accident. The key set is in how to run a Nimiq validator.
Withdraw
Withdrawing is the third step of unstaking, taking the retired balance out of the staking contract and back to an ordinary account.
It is available as soon as the retire has mined, about a minute later, and it has to take the entire retired balance. If it empties the staker record, the protocol deletes it. The step is covered in how to unstake NIM.
Checking a term on the live chain
Where a definition points at a live number rather than a protocol rule, the place to check it is the same for every term: the block explorer for blocks, batches and transactions, the validators page for the validator set and its state, and NimMap for how value and delegation move.
We publish no price figures anywhere on this site and nothing on this page is financial advice. The rest of the guides are on the Learn hub.