Indexer sources of truth
No single index answers every question. Core keeps four authorities apart per protocol, because conflating them is how a marketplace ends up trusting the wrong thing.
The four authorities
Section titled “The four authorities”Each protocol’s page names all four. Where one of them reads “no executable authority is deployed”, that is the honest reason the protocol cannot trade.
Universe-operated, external, or neither
Section titled “Universe-operated, external, or neither”Reading the primary index column tells you who you are trusting.
- Universe-operated. Ordinals reads a configured Ord server. Runes read a Universe Ord Rune index. Alkanes read a Universe Alkanes authority. OP Inscriptions read a standalone Universe indexer with a raw-block OP_RETURN scanner behind it.
- External provider. BRC-20 reads the UniSat Open API, and the registry says plainly that order freshness and inventory reconciliation are delegated there. Stamps and SRC-20 read StampDEX and Stampchain. Mezcal reads the mezcal.sh API.
- Neither, for a mutation. Seven read-only protocols record “no executable order authority is deployed” for their order book and “read authority only; no complete transferability proof” for ownership. That is not a gap in the documentation. It is the reason those protocols cannot be traded.
Three protocols go further and are read by your own browser rather than through Core at all: TAP, DMT, and UNAT deployment, mint progress, and holder figures are fetched directly from a host Universe does not operate. Those pages name the source beside the numbers. Where each number comes from covers that case in full.
Fallbacks
Section titled “Fallbacks”Most protocols have no fallback at all. Where one exists it is usually a mempool or Esplora provider used for UTXO and settlement reads, not a second opinion on protocol state. Two patterns are worth noting:
- A fallback for the base chain, not the protocol. Ordinals, Runes, Alkanes, and Mezcal list configured mempool or Esplora providers as fallbacks. Those answer “is this output unspent”, not “does this output carry a rune”.
- A fallback that is reference data only. Stamps lists an external service “for reference metadata”, and SRC-20 lists activity and mint or deploy reference data. Neither becomes an ownership authority.
An empty fallback list is a real answer. If the primary index cannot be read, that protocol has nothing to fall back to, and Core says the read failed rather than substituting something.
Checking what actually answered
Section titled “Checking what actually answered”The registry says what is configured. The live endpoint says what answered.
curl -s https://api.bitcoinuniverse.io/indexer-health \ | jq '.data[] | select(.protocolId=="ordinals") | {indexerIdentity, source, tip, nodeTip, lag, lastSuccess, status, reasonCode}'configuredIndexers.primary in that response is what the registry declared.
indexerIdentity and source are what served the request. When they differ,
believe the second pair.
Reading mempool and catalog results
Section titled “Reading mempool and catalog results”The September 6, 2026 source repair adds complete mempool membership and block transaction pagination to the Universe-operated Bitcoin adapter. These route changes have not been deployed. A candidate HTTP read against the node traversed all 4,932 transactions in one mainnet block, including an observed inscription after transaction 100. That verifies one block and the membership observed at that time; it does not establish continuous collection or a complete 30-day history.
A complete block read must reconcile unique transaction identities with the block’s reported count. A complete mempool membership read must include the whole node response. Fetching only recent transactions, stopping after a fixed number of pages, or losing a page cannot establish that the rest is quiet. Failed reads remain unavailable; only a successful, verified empty result means no entries were observed within that read’s scope.
Measured transaction weight, virtual size, fees, and transferred amounts answer different questions. An absent fee or input value remains unknown. It must not be replaced with an invented zero or estimated amount. Block weight also includes block framing, so it is not the sum of transaction weights alone. The selected network, source identity, observation time, and missing coverage must remain attached to an aggregate and its export.
The same source repair distinguishes empty catalog responses from failed reads and retains the source’s reported update time. Fetching old data again does not make it fresh. A catalog response does not prove a product is enabled, and an HTTP 503 can indicate a dependency outage as well as an explicitly disabled feature. The interface must preserve those distinctions.
These changes do not replace the external protocol sources listed above. Finding a protocol-shaped payload in a Bitcoin transaction is detection; protocol validity, ownership, and transferability still require their named authorities. Browser acceptance, deployed route verification, and complete historical coverage remain separate checks.
Every protocol
Section titled “Every protocol”| Protocol | Primary index | Fallbacks | Order book | Ownership proof |
|---|---|---|---|---|
| Bitcoin Stamps | StampDEX and Stampchain | OpenStamp for reference metadata | StampDEX Counterparty dispenser order book | StampDEX/Counterparty indexer-backed compose validation plus wallet PSBT signatures |
| SRC-20 | StampDEX | Stampchain activity; OpenStamp mint/deploy reference data | StampDEX SRC-20 order book | StampDEX one-time action challenge, seller listing PSBT, and indexed SRC-20 collateral checks |
| Ordinals | Configured Ord server output and inscription views | Configured mempool/Esplora providers for UTXO and settlement reads | Universe SQL generic marketplace order book | Seller-signed listing PSBT plus exact Ord inscription/output and Bitcoin prevout/outspend agreement |
| Runes | Universe Ord Rune index and Universe order book | Configured mempool/Esplora providers for UTXO and settlement reads | No executable order authority is deployed | Read authority only; no complete transferability proof |
| Runes (Native) | Universe Ord Rune index and Universe order book | Configured mempool/Esplora providers for UTXO and settlement reads | No executable order authority is deployed | Read authority only; no complete transferability proof |
| BRC-20 | UniSat Open API | None | UniSat Marketplace Open API | UniSat order creation/confirmation workflow |
| ARC-20 | Configured Atomicals ElectrumX/Atomicals proxy | None | Durable ARC-20 SQL listings, funded offers, reservations, orders, and broadcast lineage | Exact seller outpoint, ticker, amount, and owner proof from the configured Atomicals indexer |
| Atomicals NFTs | Configured Atomicals ElectrumX/Atomicals Marketplace authority | None | Durable Atomicals Marketplace listings, funded offers, reservations, orders, and broadcast lineage | Exact single-NFT Atomical, live Bitcoin outpoint, owner script, and Atomicals checkpoint agreement |
| Realms | Configured Atomicals ElectrumX authoritative realm authority | None | Durable Atomicals Realm Marketplace order and broadcast journal | Verified authoritative realm winner, exact single Atomical outpoint, owner script, and stable checkpoint |
| Subrealms | Configured Atomicals ElectrumX authoritative subrealm authority | None | Durable Atomicals Subrealm Marketplace order and broadcast journal | Verified authoritative subrealm winner, exact single Atomical outpoint, owner script, and stable checkpoint |
| Alkanes | Universe Alkanes authority | Configured mempool/Esplora providers for UTXO and settlement reads | No executable order authority is deployed | Read authority only; no complete transferability proof |
| Mezcal | mezcal.sh API | Configured mempool/Esplora providers for UTXO and settlement reads | No executable order authority is deployed | Read authority only; no complete transferability proof |
| TAP | Configured index-tap executable Marketplace authority | None | Durable index-tap SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Exact live TAP transfer inscription, Ord location, Bitcoin prevout and outspend, and complete 29-protocol output inventory agreement |
| DMT | Configured index-dmt executable Marketplace authority | None | Durable index-dmt SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Exact live DMT transfer inscription, Ord location, Bitcoin prevout and outspend, and complete 29-protocol output inventory agreement |
| TAP on Doge | Configured pinned Dogecoin TAP reader and Dogecoin Core | None | Durable Dogecoin-native SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Protocol-specific authoritative checkpoint ownership and exact outpoint proof corroborated by Dogecoin Core and, for TAP-DOGE, the pinned immutable TAP reader |
| DUST-20 | DUST-20 indexer discovery and portfolio data | None | Read-only legacy Universe catalog | No safe typed mutation resolver is configured |
| OP-20 | APIV4 OP-20 API with legacy fallback | Legacy API and static sample fallback data | Read-only APIV4/legacy marketplace feed | No supported mutation authority |
| OP Names | APIV4 OP Names API with legacy fallback | Legacy API and static sample fallback data | Read-only APIV4/legacy marketplace feed | No supported mutation authority |
| OP Inscriptions | Standalone OP Inscriptions indexer for catalog reads | Universe raw-block OP_RETURN scanner and SQL cache | Universe SQL OP inscription market orders | Current OPI title receipt resolved through a mempool-compatible Bitcoin API |
| OP_DROP | Configured OP_DROP marketplace v1 authority | None | Durable OP_DROP listings, funded offers, reservations, action intents, request journal, history, and settlement rows in the configured OP_DROP authority | Confirmed OP_DROP balance and custody projection, Bitcoin Core prevout agreement, exact BIP-322 actor authorization, and transferability checks |
| DROPS | Configured DROPS marketplace v1 authority | None | Durable DROPS listings, funded offers, reservations, intents, history, and settlement rows in the configured DROPS indexer | Confirmed DROPS custody projection, dual Bitcoin Core prevout agreement, BIP-322 actor authorization, and complete 29-protocol output inventory |
| CAT-20 | Configured CAT20 tracker plus Fractal Bitcoin Core read client | None | Read-only tracker order-book review | Tracker plus Fractal Bitcoin Core read validation |
| Bitmap | Configured index-bitmap executable Marketplace authority | None | Durable index-bitmap SQLite listings, revisions, funded offers, reservations, action requests, broadcast lineage, activity, and settlement observations | Authoritative first-valid Bitmap claim, live Ord location, Bitcoin Core prevout and outspend, and complete 29-protocol output inventory agreement |
| UNAT | Configured index-unat executable Marketplace authority | None | Durable index-unat SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Exact live UNAT mint inscription, authoritative membership, Ord location, Bitcoin prevout and outspend, and complete 29-protocol output inventory agreement |
| Bitcoin Names | Configured index-names executable Marketplace authority | None | Durable index-names SQLite listings, revisions, funded offers, reservations, action requests, broadcast lineage, activity, and settlement observations | Authoritative first-valid SNS registration, live Ord inscription location, Bitcoin Core prevout and outspend, and complete 29-protocol output inventory agreement |
| Doginals | Configured Doginals checkpoint authority and Dogecoin Core | None | Durable Dogecoin-native SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Protocol-specific authoritative checkpoint ownership and exact outpoint proof corroborated by Dogecoin Core and, for TAP-DOGE, the pinned immutable TAP reader |
| DRC-20 | Configured DRC-20 checkpoint authority and Dogecoin Core | None | Durable Dogecoin-native SQLite listings, revisions, funded offers, reservations, action requests, funding fences, broadcast lineage, history, and settlement observations | Protocol-specific authoritative checkpoint ownership and exact outpoint proof corroborated by Dogecoin Core and, for TAP-DOGE, the pinned immutable TAP reader |
| Rare Sats | Operator-configured local ord server with sat index | None | External marketplace required in live mode | Configured local ord index plus Bitcoin outpoint ownership |
| Ordex | Local Bitcoin Core and local ord server | Signed OpenOrdex Nostr kind-802 evidence; ord-offers/direct imports | Local Ordex journal with signed PSBT digest and source evidence | Local Bitcoin Core gettxout plus local ord claim validation |