What are Bitcoin Ordinals and Inscriptions?
👋 New to this? Just start reading at the top — it begins in plain English and gets more detailed as you scroll. Jump to any level:
🟢 The simple version
Plain English — no jargon. Start here.
Bitcoin Ordinals is a numbering system for individual satoshis (the smallest Bitcoin unit) that allows arbitrary data — images, text, code, audio — to be permanently inscribed onto specific satoshis and transferred on Bitcoin's blockchain, creating a form of NFT that lives entirely on Bitcoin without any additional protocol layer.
What Ordinals discovered — satoshis are numbered
Bitcoin has 2.1 quadrillion satoshis (100 million per BTC, 21 million BTC). Casey Rodarmor published the Ordinals protocol in January 2023 with a key observation: if you number every satoshi in the order it was mined, and define rules for tracking which satoshi ends up in which UTXO after a transaction, you get a system where individual satoshis can be uniquely identified and traded.
The Ordinals numbering system assigns a unique number to each satoshi based on when it was mined (first satoshi ever = ordinal 0, last satoshi to ever be mined will be ordinal 2,099,999,997,689,999). These numbers are deterministic — anyone running the Ordinals protocol can calculate which satoshi number is in which UTXO at any point in time.
Inscriptions — writing data onto satoshis
An Inscription attaches arbitrary data to a specific satoshi. Using Bitcoin's Taproot witness data (cheap to store since Taproot reduced witness data costs), an inscription embeds content — an image, text, a JSON file, even a video game — directly into a Bitcoin transaction. The satoshi becomes permanently associated with that content, tracked by its ordinal number. The inscription lives on Bitcoin's blockchain forever.
Why this was controversial
Bitcoin's historical consensus was that the blockchain should store only financial transactions — not arbitrary data. Ordinals exploited Taproot's SegWit discount to store large amounts of data cheaply, filling Bitcoin blocks and raising fees. Bitcoin Core developers debated whether this was a legitimate use of the protocol. Ordinals proponents argued Bitcoin has no rules prohibiting arbitrary data in witness fields — they were simply using what the protocol allows.
Is it legal in India?
Yes. Ordinals/Inscriptions are assets on Bitcoin — VDA classification applies. See India regulation.
🟡 A bit more detail
For when you want to go a little deeper.
BRC-20 tokens — fungible tokens via Inscriptions
Shortly after Ordinals launched, a developer (domo) created BRC-20 — a token standard built on top of Inscriptions. BRC-20 tokens use JSON Inscriptions to define token operations: deploy (create a new token with a name and max supply), mint (claim a quantity of that token, subject to the per-mint limit), and transfer (move tokens between addresses). BRC-20 has no smart contracts — validity is determined by indexers that read and interpret the JSON Inscriptions on-chain. The first BRC-20 tokens (ORDI, SATS) reached billions in market cap at peak in 2023.
Ordinals Inscriptions include: pixel art collections (Bitcoin Punks, Ordinal Punks — Bitcoin-native equivalents of CryptoPunks), text Inscriptions (literary works permanently on Bitcoin), music files, and entire playable games. The most valuable Inscriptions have sold for hundreds of thousands of dollars. BRC-20 tokens created a speculative token market directly on Bitcoin, generating billions in trading volume and significantly higher Bitcoin transaction fees throughout 2023. Marketplaces including Magic Eden and Ordinals Wallet support Ordinals trading.
Exotic satoshis — rare ordinals
The Ordinals protocol defines "exotic" satoshis with special properties based on their position in Bitcoin's history. Uncommon satoshis are the first satoshi of each block. Rare satoshis are the first satoshi after each Bitcoin difficulty adjustment. Epic satoshis are the first satoshi after each halving. Legendary satoshis are the first satoshi after each halving period coincides with a difficulty adjustment. Mythic satoshis: only one — the first satoshi ever mined (ordinal 0), the genesis satoshi. Exotic satoshis command premiums as "rare" Ordinals, creating a collectible market based purely on Bitcoin's own block structure.
Key Ordinals metrics: total inscriptions count (over 70 million as of 2026), BRC-20 market cap, daily inscription volume, and impact on Bitcoin transaction fees. Ordinals permanently changed Bitcoin's fee landscape — inscription activity directly competes with financial transactions for block space, benefiting miners but increasing costs for regular users. Live data: Ordinals.com · Dune Analytics (Ordinals).
🟣 The full technical picture
For the technically curious.
The Ordinals numbering algorithm
Ordinal numbers are assigned at coinbase (mining). The first satoshi mined in a block receives the next ordinal number after the highest assigned ordinal. Within a transaction, Ordinals uses a "first in, first out" rule: satoshis from input UTXOs are assigned to output UTXOs in order — the first satoshi of the first input goes to the first satoshi of the first output, and so on. This deterministic rule means any node running Ordinals software can calculate the exact ordinal number of any satoshi in any UTXO without requiring additional blockchain data beyond the standard Bitcoin chain.
Source: Rodarmor, C. (2023). Ordinals Handbook. docs.ordinals.com · Ordinals GitHub: github.com/ordinals/ord
Inscription technical mechanics — Taproot witness envelopes
An Inscription is created by spending a Taproot output whose script tree contains an "envelope" — a script fragment that pushes arbitrary data: OP_0 OP_IF [content-type bytes] OP_1 [content bytes] OP_ENDIF. This envelope is invalid (the OP_IF branch is never taken — the OP_0 ensures the condition is false), meaning it has no consensus effect. But the data is permanently stored in the transaction's witness. The Ordinals protocol defines that the satoshi at the first witness input receives the Inscription. The content-type field specifies MIME type (image/png, text/plain, application/json, etc.), allowing wallets and explorers to correctly render the content.
The Taproot witness discount is the economic mechanism that made Ordinals practical. SegWit (2017) introduced witness data as a separate block weight component charged at 1/4 the cost of non-witness data. Taproot (2021) extended SegWit's discount to all witness data including scripts. An Inscription storing a 400KB image in the witness field costs approximately the same in fees as a 100KB standard transaction — making large data storage on Bitcoin economically feasible for the first time. Critics argue this "misuses" the witness discount intended to encourage SegWit adoption for fee reduction, not arbitrary storage. Proponents argue: the protocol allows it, the fees are paid, miners benefit.
Key facts
- Created by: Casey Rodarmor (January 2023)
- Mechanism: Ordinal numbers on satoshis + Taproot witness Inscriptions
- Storage: On Bitcoin blockchain permanently (witness data)
- Token standard: BRC-20 (JSON Inscriptions, indexer-validated)
- Inscriptions count: 70+ million (as of 2026)
- Controversial: Increased Bitcoin fees, block space debate