Chain Endpoints & Indexers

Besides the primary RPC endpoint you pass to fromUrl / fromClient, some chain families consult secondary, "public-indexer-like" endpoints — fast paths and lookups that otherwise default to a public service. Every one of them can be pointed elsewhere through the chain context (ctx), so private deployments never silently depend on a public default.

All of these requests flow through the chain's fetch — a custom ctx.fetch applies to them too (see the note at the end.

Summary

Scope	Secondary endpoint	ctx option	Default
all families	CCIP REST API — lane info, message lookups by ID, execution inputs, lane latency	apiClient	https://api.ccip.chain.link
all families	CCIP v2 verifier indexers — commit / CCV lookups via getVerifications	verificationsIndexer (a per-call indexer option wins)	mainnet: https://indexer-1.ccip.chain.link, https://indexer-2.ccip.chain.link; testnet: https://indexer-1.testnet.ccip.chain.link, https://indexer-2.testnet.ccip.chain.link
TON	TonCenter v3 index — getLogs fast path, indexed tip, raw-hash tx lookups	v3Url	probed: derived from the endpoint when it is toncenter-shaped; otherwise the public TonCenter index for the network
Aptos	GraphQL indexer (queryIndexer) — getLogs fast path and execution-failure scans	indexerUrl	Aptos SDK per-network default, e.g. https://api.mainnet.aptoslabs.com/v1/graphql
Canton	CCIP CCV indexer service — verifier results and disclosure lookups	cantonConfig.indexerUrl	https://indexer-1.ccip.chain.link
EVM, Solana, Sui	none — every query rides the single RPC endpoint	—	—

All families: CCIP REST API

The shared ChainContext.apiClient accepts a URL string, a pre-built CCIPAPIClient, or null to disable the API entirely (RPC-only mode):

TypeScript

const chain = await EVMChain.fromUrl(rpcUrl, {
  apiClient: 'https://staging-api.example.com', // or a CCIPAPIClient instance, or null
})

All families: CCIP v2 verifier indexers

getVerifications races the CCIP API against the CCIP v2 verifier indexers for commit / CCV data. The built-in defaults are selected by the chain's network type; a chain-level override keeps that choice from hitting the public indexers:

TypeScript

const chain = await EVMChain.fromUrl(rpcUrl, {
  verificationsIndexer: ['https://my-indexer.example.com'],
})

A per-call indexer option (accepted by getVerifications) still wins over the ctx default; Canton additionally honors cantonConfig.indexerUrl (below).

TON: TonCenter v3 index

TON's primary API is the v2 JSON-RPC endpoint, but several operations need the separate v3 index: the getLogs fast path (startTime-only and index-hinted scans), the indexed-tip probe, the bounded-walk metadata oracle, and raw-hash transaction lookups (getTransaction('0x<64-hex>')). Point them all at one URL with v3Url:

TypeScript

const chain = await TONChain.fromUrl('https://my-v2-proxy.example/jsonRPC', {
  v3Url: 'https://my-index.example.com/api/v3?api_key=s3cr3t',
})

When v3Url is omitted, the URL is resolved (once per chain) as follows:

1. If the endpoint is toncenter-shaped (an /api/v2 path), the same-origin /api/v3 is derived (its query — e.g. an api_key — is carried over), then probed with a v3-only method (/masterchainInfo). A host that does not actually serve v3 (a v2-only proxy) falls back to the public TonCenter index for the network, so a bad inference never poisons v3 consumers.
2. Any other endpoint goes straight to the public TonCenter index (https://toncenter.com/api/v3 or https://testnet.toncenter.com/api/v3).

An explicit v3Url is taken on faith and never probed.

Aptos: GraphQL indexer

Aptos' GraphQL endpoint is its indexer: provider.queryIndexer backs the getLogs fast path and the execution-failure scans. Override it with indexerUrl:

TypeScript

const chain = await AptosChain.fromUrl('https://fullnode.example.internal/v1', {
  indexerUrl: 'https://my-indexer.example.internal/graphql',
})

When omitted, the Aptos SDK's per-network default applies (https://api.<network>.aptoslabs.com/v1/graphql). The fullnode URL is never used to infer an indexer URL — a non-standard fullnode pair requires the explicit option (note that a Network.CUSTOM Aptos config throws without one).

Canton: CCIP CCV indexer

Canton's CCV verifier results and disclosure lookups go through the CCIP CCV indexer service, configured as part of the Canton config:

TypeScript

const chain = await CantonChain.fromUrl(ledgerUrl, {
  cantonConfig: {
    // ...
    indexerUrl: 'https://my-ccv-indexer.example.com',
  },
})

Default: https://indexer-1.ccip.chain.link (the first mainnet verifier indexer).

Fetch overrides

A custom ctx.fetch is used verbatim for every request above (primary and secondary alike). TON and Aptos additionally accept dedicated fetch overrides for their index traffic (ctx.v3Fetch for TON — built automatically from the resolved v3 URL when omitted), since the index host's rate-limit profile differs from the RPC host's.