The parts that make this work
Shards and chunks
NEAR is one chain whose state is split by account into shards: in October 2026 there were ten, with ids 1, 4, 6 and 7 to 13 (the gaps are shards that were split in two). The split follows account names; aurora and game.hot.tg, two of the busiest accounts, mark shard boundaries. There's still only one chain of blocks. Each block holds one chunk per shard: the transactions and receipts that shard processes at that height. If a shard's chunk doesn't arrive in time, the block goes ahead without it and that shard's state simply doesn't move for that block. This design is called Nightshade. Adding shards adds capacity, and NEAR has been splitting busy shards as traffic grows.
Validators and their roles
On October 5, 2026, epoch 4,835 had 415 validators staking about 546 million NEAR, out of a supply of 1.31 billion. The 100 largest are block producers and hold about 506 million of it; each is also a chunk producer for one shard, ten per shard. For every height, one block producer is picked by stake for the block, and one chunk producer per shard for its chunk. All 415, small ones included, act as chunk validators. An epoch is 43,200 blocks, about seven hours, and the validator set and shard assignments change between epochs. Validators that produce less than 80 % of the blocks or chunks expected of them are kicked out for the next epoch. New NEAR is minted at up to 2.5 % a year (halved from 5 % in late 2025), and it all goes to validators and their delegators.
Stateless validation
Since August 2024, chunk validators don't keep the state of the shards they check. A chunk producer sends them a state witness along with the chunk: the parts of the shard's state that the chunk touches, with proofs that they match the state root. A validator can re-run the chunk from that witness alone and sign an endorsement if the result matches. For each shard and height, about 80 validators are sampled by stake; a chunk goes in a block only once validators holding more than two thirds of their combined stake have endorsed it. Every block header carries a bitmap of who endorsed each chunk. Because the sample changes every height, an attacker can't predict which validators will check a given chunk.
Doomslug and finality
Block production follows Doomslug. When a block producer receives a block, it sends an approval to the producer of the next height. The next block can only be made with approvals from producers holding more than two thirds of the stake; if the expected block doesn't come, producers send skip approvals instead, and a later height takes over. Once a block's approvals are included in the block right after it, the block is doomslug final: reverting it would get someone slashed. It's fully final when two blocks at consecutive heights have been built on it: block h is final once h + 1 and h + 2 exist. With blocks every 0.6 seconds, that's about 1.2 seconds. Every header names its last final and last doomslug-final block, which is how live mode colours the strip.
Receipts: transactions across shards
A NEAR transaction doesn't run everywhere at once. It's first converted into a receipt on the signer's shard, where its fee is charged. The receipt then executes on the receiver's shard, in the same block if both accounts share a shard, otherwise in the next. A contract call that calls another contract produces more receipts, each a block later, and refunds come back the same way. So a simple transfer settles in one or two blocks, and a call chain across shards takes a few. Blocks carry far more receipts than transactions; live mode's feed lists the transactions.
What live mode shows
Live mode asks NEAR's public JSON-RPC (rpc.mainnet.fastnear.com, with rpc.mainnet.near.org standing in when it's unavailable) for the newest block once a second. Blocks come faster than that, so it shows about every other one; each card's tooltip says how many came in between. From each block it reads the block producer, every chunk's gas, missing chunks, the number of approvals and of endorsements per chunk, and which blocks the header calls final. The ring is the current epoch's validator set from the same RPC. Every eight seconds it also loads one recent final block in full from mainnet.neardata.xyz to list its transactions. These are free public services that limit requests, so an endpoint that refuses is left alone for 30 seconds. Endorsement bitmaps say how many validators endorsed but not which, chunk headers don't name their producer, and approvals aren't attributed here, so those beams replay the real counts on random validators.
What the animation simplifies
A real block takes about 0.6 seconds, so step-by-step mode stretches one over about 15 seconds and shows its steps one after another. On the real network they overlap: chunk producers for the next height start as soon as a block arrives, and approvals for one block travel while chunks for the next are being endorsed. The simulated stakes and shard assignments are the real ones from October 5, 2026; the transactions and receipts are illustrative. Sources: the Nomicon consensus spec, NEAR's validator and architecture docs, Near One's posts on validator sampling and the 2.5 % inflation upgrade, and the mainnet RPC itself.