Outpost

An outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. is a smart contractSmart Contract Deterministic code deployed on a blockchain. The same inputs always produce the same output, and the output is verifiable by anyone. deployed on an external chain (not ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data.) that does two things: lets validatorsValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. prove their identity so they can register as indexersIndexer A node that reads blockchain data from a source chain, parses it into structured documents, and writes them to defraDB. Indexers are write-only: they push data out over P2P and reject all incoming replication., and lets users pay for viewView A curated, SDL-defined representation of defraDB documents. Views transform raw indexed data into a structured output shape. access without interacting with ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data. directly.

OutpostsOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. are how external chains connect into the Shinzo network. They handle source chainSource chain Any external blockchain that Shinzo indexes — Ethereum, an L2, a Cosmos chain, etc. A source chain hosts an outpost contract and is read by indexers. local logic. Relayers bridge the results to ShinzoHub.

Why outposts exist

ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data. cannot directly verify that a validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. on another chain is who they claim to be. Every chain has its own consensus mechanism and key types. The outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. runs on the same chain as the validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer., where that chain's native tools can verify identity.

OutpostsOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. also handle payments. Users on external chains should be able to pay in their chain's native currency without bridging tokens to ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data. first.

Validator assertions

An assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. is a cryptographic proof that a validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. on an external chain is who they claim to be. This is a prerequisite for becoming an indexerIndexer A node that reads blockchain data from a source chain, parses it into structured documents, and writes them to defraDB. Indexers are write-only: they push data out over P2P and reject all incoming replication.. A validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. cannot register as an indexerIndexer A node that reads blockchain data from a source chain, parses it into structured documents, and writes them to defraDB. Indexers are write-only: they push data out over P2P and reject all incoming replication. directly on ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data.; they must go through the assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. process on their source chainSource chain Any external blockchain that Shinzo indexes — Ethereum, an L2, a Cosmos chain, etc. A source chain hosts an outpost contract and is read by indexers. first.

The flow:

1. The indexerIndexer A node that reads blockchain data from a source chain, parses it into structured documents, and writes them to defraDB. Indexers are write-only: they push data out over P2P and reject all incoming replication. generates an operator (delegate) key locally.
2. The validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer.'s withdrawal keyWithdrawal Key On Ethereum, the key that controls a validator's stake withdrawals. The outpost requires the withdrawal key to sign the EIP-712 assertion digest — it is the chain's strongest proof that a given party controls the validator. calls the outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation., providing their consensus public key and the operator pubkey, and signs the assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. digest.
3. OutpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. verifies the validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. using the chain's native mechanism, stores the signed assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub., and emits an AssertionSigned event.
4. A relayer picks up the event and broadcasts MsgIndexerAssertion to ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data..
5. ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data. verifies the assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. and records a slip for the operator pubkey. The indexerIndexer A node that reads blockchain data from a source chain, parses it into structured documents, and writes them to defraDB. Indexers are write-only: they push data out over P2P and reject all incoming replication. can now register in the Indexer RegistryIndexer Registry The ShinzoHub EVM precompile at `0x0212` that tracks registered indexers. An indexer cannot register here directly — it must first complete an assertion via an outpost contract. The registry verifies the stored assertion before accepting registration. (0x0212), signing the registration with its operator keyOperator Key Also called the delegate key. Generated locally by an indexer operator and bound to a validator's identity through an assertion. The indexer uses it to sign ShinzoHub registrations and protocol actions..

The digest

The outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. generates a hash that both parties must sign. The digest includes the assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. ID, withdrawal address, delegate key, consensus keyConsensus Key The public key a validator uses to sign blocks and participate in chain consensus. During an assertion, this key is bound to an operator key so the indexer can act on the validator's behalf on ShinzoHub. hash, creation time, and signature deadline.

How the digest is computed depends on the implementation. Different chains have different hashing and signing conventions. The requirement is that the digest is deterministic and includes enough context to prevent replay attacks across chains.

EVM implementation

On Ethereum, the outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. contract (IndexerAssertion) uses EIP-712EIP-712 An Ethereum standard for signing structured, typed data in a form users can read before approving. The EVM outpost contract uses EIP-712 for the digest that a validator's withdrawal key signs during an assertion. typed data signatures. The validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer. opens an assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. with createAssertion, then submits the withdrawal-key signature with submitAssertionSignature. The contract emits AssertionSigned, which the relayerRelayer A process that moves data between chains. Shinzo uses two that share nothing but the name: the EVM relayer bridges Ethereum to ShinzoHub, and Hermes bridges ShinzoHub to SourceHub over IBC. subscribes to:

The relayerRelayer A process that moves data between chains. Shinzo uses two that share nothing but the name: the EVM relayer bridges Ethereum to ShinzoHub, and Hermes bridges ShinzoHub to SourceHub over IBC. reads the assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. fields from the event logLog A document type the indexer produces for event logs emitted during transaction execution. `topics` holds the indexed parameters and `data` holds the non-indexed ones, both as raw hex. ABI decoding happens later, in a lens. and forwards them to ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data.. There is no extraData tagging and no dependency on who built the block, which matters on mainnet where MEV-boostMEV-boost A service on Ethereum that lets validators hand off block construction to external builders. Because those builders control the block's `extraData` field, Shinzo's assertion design does not rely on it — validator identity is read directly from the outpost event instead. builders construct the block header (including extraData) on the validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer.'s behalf.

Chain-specific verification

The verification step is what makes each outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. implementation different. The concept is always the same (prove you are a validatorValidator An entity that participates in a chain's consensus. On Ethereum, a validator's withdrawal key signs an EIP-712 message on the outpost to authorize an operator key as its indexer.), but the proof mechanism depends on the chain.

Some chains let you query the staking moduleModule A Cosmos SDK building block that owns a slice of chain state, handles messages, and emits events. ShinzoHub adds five custom modules (`x/admin`, `x/sourcehub`, `x/host`, `x/indexer`, `x/view`) on top of the standard Cosmos set. to check if an address is bonded. Some use block production as proof. Others might use multisig schemes or oracle attestations. The outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. interface does not prescribe a mechanism. Each implementation uses whatever works on its chain.

Payments

Users on external chains can pay for Shinzo resources without interacting with ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data..

1. User calls payment() with a resource type, their DIDDID A self-sovereign identifier (e.g., `did:key:z6Mk...`) derived from a public key. Hosts, indexers, and users are identified by DIDs in SourceHub authorization tuples., a stream IDStream ID A unique identifier assigned to a curated data feed when it is registered., and an expiration duration.
2. The contract stores a PaymentReceipt and emits a PaymentCreated event.
3. A relayer picks up the event and delivers it to ShinzoHubShinzoHub Shinzo's coordination chain: a Cosmos SDK chain (v0.53.4) with an integrated EVM, running CometBFT consensus. It holds the view, host, and indexer registries and the economic layer (staking, pricing, payments). It does not store or serve indexed blockchain data. as MsgRequestStreamAccess.

Implementations

Implementation	Chain type	Status
shinzo-outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation.	EVMEVM The runtime that executes Solidity smart contracts. ShinzoHub embeds an EVM module so its registries are accessible as precompiled contracts at fixed addresses, callable from any EVM tooling. (Ethereum, L2s)	Complete
Cosmos outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation.	Cosmos SDKCosmos SDK A Go framework for building app-specific blockchains. ShinzoHub (v0.53.4) and SourceHub are both Cosmos SDK chains. ShinzoHub also bundles an EVM module. chains	Not yet implemented
CosmosEVM outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation.	Hybrid Cosmos+EVMEVM The runtime that executes Solidity smart contracts. ShinzoHub embeds an EVM module so its registries are accessible as precompiled contracts at fixed addresses, callable from any EVM tooling. chains	Not yet implemented

Each chain type gets its own outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. implementation. The verification mechanism can be completely different as long as the output (a signed assertionAssertion A cryptographic proof, produced on a source chain, that a validator is who they claim to be. It ties the validator's consensus identity to an operator key. Without a valid assertion, a validator cannot register as an indexer on ShinzoHub. that a relayerRelayer A process that moves data between chains. Shinzo uses two that share nothing but the name: the EVM relayer bridges Ethereum to ShinzoHub, and Hermes bridges ShinzoHub to SourceHub over IBC. can deliver) follows the same format. A Cosmos outpostOutpost A smart contract deployed on a source chain. Validators call it to prove their identity before registering as indexers; users call it to pay for view access in the source chain's native currency. Each chain type has its own outpost implementation. would be a CosmWasm contract querying the staking moduleModule A Cosmos SDK building block that owns a slice of chain state, handles messages, and emits events. ShinzoHub adds five custom modules (`x/admin`, `x/sourcehub`, `x/host`, `x/indexer`, `x/view`) on top of the standard Cosmos set.. For CosmosEVM chains, a Solidity contract could call the staking precompilePrecompile A contract at a fixed EVM address implemented in native Go rather than Solidity bytecode. ShinzoHub's three registries (View `0x0210`, Host `0x0211`, Indexer `0x0212`) are precompiles so they can call Cosmos SDK keepers directly and trigger ICA packets. at 0x0800.