Glossary

API Key

A credential authenticating your requests to a service. On Instanodes, the key sits embedded directly in the RPC endpoint URL.

Appchain

A blockchain built for a single application, not for hosting many unrelated ones, with its own custom rules, governance, and often its own token.

Archive Node

A node retaining the full historical state of a blockchain, not only recent blocks, needed for queries about any past point in chain history.

Compute Unit / Request Unit

A billing measure some providers use, charging different amounts for different API methods based on computational cost. Instanodes bills flat request counts instead, not compute units.

Data Availability (DA) Layer

The system responsible for making a rollup's transaction data publicly accessible, so anyone verifies or reconstructs chain state, independent of the rollup's own sequencer.

Dedicated Node

Infrastructure reserved exclusively for one customer, as opposed to a shared node used by multiple accounts.

Failover

The automatic process of redirecting traffic to healthy infrastructure when a server, node, or region becomes unavailable.

JSON-RPC

A lightweight remote-procedure-call protocol encoded in JSON, used by Ethereum and many other chains to expose blockchain data and functions over HTTP or WebSocket.

MEV (Maximal Extractable Value)

Value extracted by reordering, inserting, or censoring transactions within a block, relevant to validator and sequencer operation.

Node

Software maintaining a copy of a blockchain's data and participating in validating or relaying transactions.

Prover

In a rollup, particularly a zero-knowledge rollup, the component generating cryptographic proofs confirming transactions executed correctly.

RPC (Remote Procedure Call)

A protocol letting a program request data or execute a function on a different system, in this context, querying or interacting with a blockchain node.

Rollup

A layer-2 scaling solution executing transactions off the main chain and periodically committing a summary (and, depending on the rollup type, proofs) back to the base layer.

Sequencer

The component in a rollup responsible for ordering transactions before batching and submission to the base layer.

Shared Node

Infrastructure serving multiple customers at once, each with its own account-level access, as opposed to a dedicated node.

SLA (Service Level Agreement)

A contractual commitment defining a service's guaranteed performance, most commonly uptime, along with remedies if the commitment goes unmet.

Slashing

A penalty in proof-of-stake networks where a validator forfeits a portion of staked assets for provable misbehavior, such as double-signing.

Uptime

The percentage of time a service stays operational and available, typically measured over a rolling period (for example, 90 days) and expressed as a percentage such as 99.95%.

Validator

A network participant responsible for proposing and attesting to blocks in a proof-of-stake blockchain, earning rewards for correct participation and facing penalties for misbehavior or downtime.

WebSocket

A persistent, two-way communication channel over a single connection, used for push-based data, such as new blocks or pending transactions, instead of repeated polling.