# ARC-20 and Atomicals

Atomicals' fungible ARC-20 tickers, whose units ride sats, and its NFTs (containers and dmitems). One definitional indexer, one quarantine, one named gap: realms.

URL: https://blockspace.wiki/protocols/arc-20-and-atomicals/

Atomicals defines two kinds of token that BTI measures. [ARC-20](https://blockspace.wiki/glossary/arc-20/) tickers are fungible, and the books keep them under the key `arc20`. Atomicals NFTs, [containers and dmitems](https://blockspace.wiki/glossary/atomicals-container/), are a second family, `atomicals-nft`. Both are catalogued by one adapter, as BTI's rule of one adapter per indexer requires: "atomicals catalogues ARC-20 AND the NFTs".

## How Atomicals puts data on Bitcoin

Atomicals writes to the witness. The data-types reference lists it among the envelope protocols and gives its marker, `atom`, among those a reader scans for inside an `OP_FALSE OP_IF … OP_ENDIF` block. The Atomicals observation says every `atom` witness envelope ever revealed "remains consensus-valid data".

An Atomical's identity comes from its commit. Ruleset v1's fact table gives it as `atomical_id = commit_txid ‖ LE32(commit_vout)`: the commit transaction's id followed by the commit output's number. A ticker or a container name is an alias.

ARC-20 is coloured sats. The token table says "one unit = one sat by protocol design — the units RIDE sats, the ticker is the claimant". The Atomicals observation adds the consequence: spent through a wallet that does not know the protocol, the units scramble or burn under the protocol's own rules. BTI's token table writes it as "decays by scrambling"; the observation calls it [decay-by-amnesia](https://blockspace.wiki/glossary/decay-by-amnesia/).

## How BTI attributes the bytes

The atomicals adapter reads atomicals-go, an indexer with its own database. Its trust is "definitional" in the [trust triad](https://blockspace.wiki/glossary/trust-triad/): the indexer's ruleset is the protocol. It has two modules, `arc20` and `atomicals-nft`. The ruleset's facts and the adapters table record four quirks:

- **NFT binding is outpoint-positional**, and the rule forks at block 819,181 (raw input index before, first-in-first-out after). BTI does not re-derive it and adopts the source's verdicts.
- **A quarantine.** From block 848,521 atomicals-go writes negative amounts into its own ledger, a bug measured at 131,329 lines in 65,036 transactions. Rows that touch one are quarantined: they get no supply change and are counted, and their claims stand. The owner ruled on 2026-08-11 that "the source ledger is corrupt state, not protocol state".
- **Some measured scramble is the implementation's.** Before the fork, part of what measures as scramble is atomicals-go burning where the reference would colour an exact-remainder output. BTI adopts it under the writer rule and records it.
- **Realms are a named gap.** The source holds zero [realms](https://blockspace.wiki/glossary/atomicals-realm/) against about 28 % of the footprint (verified 2026-08-10). The adapter fails closed, the gap is counted per window and claimed by nobody, and a test turns red the day realm rows appear.

Two more rulings narrow the family. `Dmint` is a mint rule, a state field, not an object. A container's membership is a group: it has aggregated books but claims nothing.

ARC-20 carries no file in the books. Its [Book C](https://blockspace.wiki/glossary/book-c/) is 0, and its weight is structure and overhead.

## Live figures

ARC-20 tickers (as of block 972,299, 2026-10-20 09:30:48 UTC):

| measure | value |
|---|---|
| Book A | 4.95 GB |
| share of the chain's bytes (Book A) | 0.64 % |
| share of all Book A bytes | 3.70 % |
| tickers | 657 |
| operations | 8,284,671 |
| first height | 808081 |

Atomicals NFTs (as of block 972,299, 2026-10-20 09:30:48 UTC):

| measure | value |
|---|---|
| Book A | 0.07 GB |
| share of the chain's bytes (Book A) | 0.01 % |
| tokens | 32,230 |
| operations | 32,517 |
| first height | 808579 |
| last height | 929700 |

The token table counted 1,766 containers and 30,464 dmitems on 2026-08-10, 32,230 in all.

Holders: read on 2026-10-20, the leaderboard's coverage table placed 99.96 % of ARC-20's Book A on 105,769 addresses, with 302 of the 657 tickers having a holder. It placed 98.24 % of the NFTs' Book A on 8,249 addresses.

## The natural experiment

The Atomicals observation, a companion to [Blockspace Value Theory](https://blockspace.wiki/glossary/bvt/), proposes that Atomicals is "the control group BVT has been missing": its consumption is permanent, its interpretation layer died but can be rebuilt from chain data and published rules, and its live supply shrinks with every spend by a wallet that does not know the protocol. It lists what can be measured, among them total kB consumed and live against destroyed supply over time. That is a proposal, not a measured result; see [Atomicals as a natural experiment](/concepts/atomicals-natural-experiment/).

## Not covered by a source

Blockspace Holdings' documents give no bytes:vbytes ratio for Atomicals, and no measured decay-by-amnesia curve. They do not describe the `atom` envelope's fields beyond its marker.

Sources:

- Blockspace Holdings records
- block.space docs: data types · https://block.space/docs/datatypes
- block.space docs: Atomicals · https://block.space/docs/atomicals
- Atomicals as a natural experiment for BVT · https://block.space/docs/atomicals
- block.space protocols API · https://block.space/api/protocols
- block.space leaderboard coverage API (holders measured per protocol) · https://block.space/api/leaderboard/coverage

Live figures: protocols as of block 972,299, 2026-10-20 09:30:48 UTC

Updated: 2026-10-20