ElectrumX reference

What ElectrumX is here

Atomicals ElectrumX reads Bitcoin blocks and applies the Atomicals protocol rules. It is where protocol interpretation happens. Everything downstream is a projection of what it reports.

The pinned baseline for this documentation is release v1.5.2.0, commit 8df23747, released on 2025-03-27. That baseline is preserved as a historical reference and is not rewritten when a Universe service upgrades.

The version handshake

A consumer must check compatibility before trusting anything a provider reports. The Universe NFT and Realm index does exactly that, and refuses a provider that does not match:

Field	Checked against
Version	The pinned provider version
Tag	The pinned provider tag
Commit	The pinned provider commit
Implemented AIPs	The exact required set, [1, 3]
Network	The configured network

An exact AIP set is required. A provider reporting a different set, in a different order, or a different length is rejected rather than accepted with a warning.

See Atomicals Improvement Proposals.

Methods the Universe projection relies on

Method	Used for
server.info	The version and AIP handshake above
blockchain.atomicals.get_global	The provider’s current tip and global state
blockchain.atomicals.list	Enumerating Atomicals for the scan
blockchain.atomicals.get_location	Resolving where an Atomical currently sits

The Marketplace authority additionally reads:

Method	Used for
blockchain.atomicals.at_location	Confirming exactly one authoritative asset at an outpoint
blockchain.atomicals.listscripthash	Confirming exactly one active row whose coloured balance is the full output value
blockchain.atomicals.get_by_ticker	Resolving a ticker to its verified winner

Those two lists are the write capability boundary as well: the projection declares no write capabilities.

Caching and consistency

Three rules:

1. Never cache a result without its chain position. A response is only true at the tip it was computed at.
2. Never mix positions. Two calls at different tips produce an inconsistent picture. Bracket related calls and abort if the tip moved.
3. A generation spanning more than one provider tip is mixed. The Universe index publishes such a generation explicitly as mixed and stale rather than presenting it as consistent.

Activation sensitive behavior

Some responses depend on rules that activate at a height, per network. A method that returns one answer today can return a different one for the same historical transaction under a different revision.

Record the provider version, the network, and the height with every stored answer. See activation boundaries.

Official against proxy behavior

Layer	What it is
Official Atomicals ElectrumX	The protocol authority. Its behavior is protocol behavior
A Universe proxy or gateway	Transport, authentication, and shaping in front of it
A Universe index	A materialised projection with its own generation model

Only the first is protocol behavior. Anything added by the second or third is Universe implementation and is labelled as such throughout this documentation.

Source

Indexer and validator dependency and source of truth.