Bitcoin Stamps is a protocol for embedding image data directly into Bitcoin transaction outputs (UTXOs) so that the data cannot be pruned by any Bitcoin full node. The creator, Mike In Space, launched it in March 2023 as a response to a then-active threat from Bitcoin Core developer Luke Dashjr to strip out Ordinals' witness-data inscriptions. Stamps puts the data somewhere Core cannot remove without breaking consensus.

The trade-off is severe. Stamps consume substantially more block space per byte of stored content than Ordinals do, transaction fees are correspondingly higher, and the original image size limit was 24 × 24 pixels at 8-bit color depth. In exchange, the data is genuinely permanent in a way nothing else on Bitcoin currently matches.

The motivation: prunability

Ordinals inscriptions live in Bitcoin's witness data. SegWit, which introduced witness data in 2017, was designed with the understanding that this data could theoretically be discarded by nodes after some confirmation depth. The Bitcoin Core source code has long had configurable options around witness retention. In practice, all major Bitcoin Core releases retain witness data indefinitely, but the architectural possibility of pruning has always existed.

Luke Dashjr made this concrete in late 2023 when he stated publicly that he considered Ordinals to be "exploiting a vulnerability" and planned to address it in a future Bitcoin Core release. His proposed change would have used the existing -datacarriersize filter to limit inscriptions. The threat didn't materialize as a successful protocol change, but it sat as a live possibility throughout 2023-2024 and shaped how the Bitcoin NFT community thought about permanence.

Mike In Space proposed Stamps as a hedge. If Ordinals data is in a part of Bitcoin that could theoretically be filtered or pruned, put the data somewhere Bitcoin nodes have no choice but to keep.

The mechanism: data in spendable outputs

The Stamps protocol encodes image data as a base64 string, prefixes it with STAMP:, and embeds the result into the description key of a Counterparty issuance transaction. This produces a sequence of multisignature outputs (P2SH) that hold the data across multiple outputs in the Bitcoin blockchain's UTXO set.

UTXOs are the spendable outputs that represent Bitcoin balances. Every full node must maintain the complete UTXO set to validate transactions. Removing data from a UTXO would change the set, which would break consensus with the rest of the network. So as long as the Bitcoin protocol works, the UTXO set must be preserved, and the data Stamps embeds within it must be preserved with it.

This is the architectural guarantee Stamps provides that Ordinals doesn't. Witness data could in principle be pruned. UTXO-set data cannot be, without breaking Bitcoin itself.

The size and cost trade-off

Stamps' permanence comes at real cost. The protocol's original guidance was 24x24 pixel images with 8-bit color depth in PNG or GIF format. This is enough for pixel art, simple icons, and basic visual symbols, but nowhere near the resolution available to Ordinals (4 MB inscriptions, effectively unlimited image complexity).

The size constraint flows from the UTXO encoding. Each P2SH output can carry a limited number of bytes. Larger images require more outputs, which means larger transactions, which means higher fees. A Stamps transaction at peak Bitcoin fee periods can cost tens of dollars; the same image as an Ordinal inscription is typically a few dollars. For the same image as a Counterparty NFT with off-chain hosting, the cost is just the standard Counterparty issuance fee plus the BTC transaction fee.

The fee differential is the main reason Stamps adoption has been more measured than Ordinals. Most users who want Bitcoin NFT exposure choose Ordinals for cost or Counterparty for feature richness. Stamps appeals specifically to users who prioritize architectural permanence over those other considerations.

SRC-20: fungible tokens on Stamps

SRC-20 is the Stamps equivalent of BRC-20. Like BRC-20 on Ordinals, SRC-20 uses the underlying inscription mechanism to encode fungible token operations (deploy, mint, transfer) as structured data. The architectural difference is the storage layer: BRC-20 lives in Ordinals witness data, SRC-20 lives in Stamps UTXOs.

SRC-20 launched alongside the Stamps protocol in March 2023. By the time the SRC-20 ecosystem had developed, several tokens had emerged as significant: STAMP, BITDN, and KEVIN among the early successes, with PEPE and others following. As of mid-2024, the top SRC-20 tokens had a combined market cap in the low nine figures, a fraction of BRC-20's peak but a meaningful ecosystem of its own.

SRC-20's pitch over BRC-20 is the same as Stamps' pitch over Ordinals: greater permanence at higher cost. Users who prefer the permanence trade tokens on the Stamps side; users who prefer the cost-efficiency trade on the Ordinals side. The two ecosystems coexist without much direct competition.

SRC-721: NFTs on Stamps

SRC-721 is an NFT standard that builds on Stamps the way ERC-721 builds on Ethereum's base layer. It uses the Stamps storage mechanism for the underlying image data and adds metadata conventions for NFT-like properties (collection membership, traits, etc.).

SRC-721 collections are smaller in 2026 than either Counterparty assets or Ordinals inscriptions, but they exist as a distinct collector category. The use case overlaps significantly with Ordinals inscriptions; the choice between them comes down to whether the issuer prioritizes Stamps' permanence guarantee or Ordinals' cost-efficiency and existing market depth.

Where Stamps fits in 2026

Stamps occupies a specific niche in the broader category of bitcoin nfts. It's the answer for users who want the absolute strongest permanence guarantee available, are willing to accept the size and cost constraints, and want a smaller, more committed community over the larger, more speculative Ordinals ecosystem.

Some specific use cases where Stamps makes sense:

  • Long-term archival of small visual or textual artifacts where the goal is multi-decade durability.
  • Cultural artifacts intended to persist regardless of future Bitcoin Core decisions about witness data.
  • SRC-20 token launches by communities that explicitly value the Stamps permanence narrative.

For everything else, Ordinals or Counterparty are usually better fits. The Bitcoin NFT category in 2026 is genuinely a three-protocol space, and Stamps' role is the specialist option rather than the default. That's a reasonable place to be, and the protocol's continued operation since March 2023 suggests the community supporting it is sized appropriately to its niche.