Arbitrum
Arbitrum is the Ethereum Layer 2 rollup ecosystem from Offchain Labs. It includes Arbitrum One (general-purpose rollup secured by Ethereum), Arbitrum Nova (AnyTrust chain for high-throughput, low-cost apps), Arbitrum Sepolia (testnet), and Arbitrum Orbit (settlement framework for custom L2 / L3 chains). Developers interact via standard Ethereum JSON-RPC, the Stylus SDK for Rust / C / C++ smart contracts, the Arbitrum SDK for cross-chain messaging and bridging, and the Arbitrum Bridge for canonical asset transfer between Ethereum and Arbitrum chains.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Arbitrum the way a machine reads it — 18 machine-readable artifacts across 10 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Arbitrum scores 47.4/100 (developing), with a separate agent-readiness read of 44/100 (agent aware). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
How we profile Arbitrum
Each block below is one kind of artifact we hold for Arbitrum. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 10
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Arbitrum One JSON-RPC
Public Ethereum JSON-RPC endpoint for Arbitrum One mainnet (chain ID 42161), the flagship optimistic rollup secured directly by Ethereum L1. Supports standard eth_* methods plus...
Arbitrum Nova JSON-RPC
Public Ethereum JSON-RPC endpoint for Arbitrum Nova (chain ID 42170), an AnyTrust chain with a Data Availability Committee for high-throughput, low-cost transactions suited to g...
Arbitrum Sepolia JSON-RPC
Public Ethereum JSON-RPC endpoint for the Arbitrum Sepolia testnet (chain ID 421614).
Arbitrum Bridge
Canonical cross-chain bridge for transferring ETH and ERC-20 tokens between Ethereum L1, Arbitrum One, Arbitrum Nova, and connected Orbit chains. Bridge operations and underlyin...
Arbitrum SDK
Official TypeScript SDK (@arbitrum/sdk) for cross-chain interactions — building L1-to-L2 and L2-to-L1 messages, deposit and withdrawal flows, retryable tickets, and gas estimati...
Stylus SDK (Rust)
Stylus lets developers write EVM-compatible smart contracts in Rust, C, and C++ that compile to WASM and run alongside Solidity contracts. The Rust SDK provides storage primitiv...
Arbitrum Nitro
Open-source Nitro node implementation that runs Arbitrum One, Nova, and Orbit chains. Includes the sequencer, batch poster, validator, and a fork of go- ethereum patched for Arb...
Arbitrum Orbit SDK
TypeScript SDK and tooling for deploying and operating Orbit chains — custom Arbitrum L2 / L3 chains that settle to Arbitrum One, Nova, or other Orbit chains.
Arbiscan Block Explorer
Etherscan-family block explorer for Arbitrum One, Nova, and Sepolia with a public REST API for contracts, transactions, and addresses.
Arbitrum JSON-RPC API
Ethereum-compatible JSON-RPC 2.0 endpoint
Scroll within the panel for all 10 ·
Open Collections 1
Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.
Open, tool-agnostic API collections (OpenAPI-derived and Bruno).
Arbitrum JSON-RPC API
OPEN COLLECTIONPricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.
Published pricing tiers and plan structures.
Rate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Arbitrum Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Arbitrum Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Arbitrum Public WebSocket APIs
AsyncAPI description of the WebSocket surface that Arbitrum exposes from publicly documented endpoints. ## Important scope notes (from Arbitrum docs) Arbitrum's public RPC endpo...
ASYNCAPISpectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Arbitrum API Rules
SPECTRALSecurity Posture 1
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Arbitrum — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 1
Portal, sign-up, and the first successful call
Documentation 1
Reference material describing how the API behaves
Agent Surfaces 2
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 1
Authentication, authorization, and security posture
Operate 2
Status, limits, changes, and where to get help
Company 3
The organization behind the API
Other 2
Properties that don't map to a standard resource type
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