Ordinals & Inscriptions

💡 The Plain-English Definition

Ordinals is a protocol that assigns a unique serial number to every satoshi (the smallest unit of Bitcoin — 0.00000001 BTC) ever mined. Inscriptions attach arbitrary data — images, text, code, video — to specific satoshis, creating Bitcoin-native digital artifacts permanently stored on the blockchain.

🤔 But Why Though?

Casey Rodarmor launched the Ordinals protocol in January 2023 with a simple but far-reaching idea: since satoshis are mined in a specific order and transferred through transactions in a predictable way, you can track individual satoshis across the blockchain. The tracking uses a FIFO (First In, First Out) rule: the first satoshi of an input is assigned to the first satoshi of the first output, preserving identity through transactions. This creates a numbering scheme where every satoshi has a unique ordinal number from 0 (the first satoshi ever mined) to approximately 2.1 quadrillion (the last satoshi that will ever be mined).

Inscriptions build on this: by attaching arbitrary data to specific satoshis using Bitcoin’s witness data (the part of a transaction that holds signatures, discounted in block weight by SegWit, the 2017 upgrade that changed how transaction data is measured), those satoshis become carriers of content — permanently, immutably stored on the Bitcoin blockchain. The technical mechanism uses a two-step commit/reveal: a transaction first commits to a Taproot (the 2021 Bitcoin upgrade) script containing the inscription data, then a second transaction spends that output, revealing the data in the witness field. The data is stored in a standard tapscript envelope using OP_FALSE OP_IF instructions that are never executed — making the data present on-chain without affecting transaction validity.

The controversy is genuine and worth presenting honestly. Critics argue that Ordinals consume block space that Bitcoin was designed for financial transactions, drive up fees for regular users, and store content (JPEGs, memes) that has no place in a monetary network. Proponents argue that Ordinals demonstrate Bitcoin’s programmability, generate fee revenue that strengthens long-term miner security, attract developer activity, and that block space is a market — anyone willing to pay the fee is entitled to use it. Bitcoin Core v30.0’s removal of the OP_RETURN 80-byte limit in October 2025 partially reflects the pragmatic view that the data will end up on-chain regardless of node policies. Bitcoin Knots (the alternative Bitcoin implementation maintained by Luke Dashjr) offers filtering as an option for operators who want to exclude inscription transactions.

🌍 The Real-World Analogy

Think of the Bitcoin blockchain like a town’s official record book — historically used only for property deeds and legal agreements. Ordinals and Inscriptions are like someone discovering the record book’s paper is archival quality and deciding to press flowers into the margins, attach photographs to pages, and store art between the legal entries. Traditionalists argue the record book’s paper is too precious for flowers — it’s for legal documents only. Others argue that if the paper is valuable enough for someone to pay the premium to use it, the flower pressing is a legitimate use of a public resource.