Chain49 API

Name: Chain49 API API
Brand: Chain49 API
Availability: InStock

✓ Official Vendor SpecFinanceBankingapiKey20 EndpointsREST

For Agents

Read blocks, transactions, addresses, xpubs, UTXOs, NFTs, and mempool data and broadcast transactions across 10+ blockchains via Chain49's hosted Blockbook-compatible API.

Quickstart

Get started with Chain49 API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"get an address balance on a blockchain"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Chain49 API API.

List the blockchains Chain49 currently exposes and read each chain's summary info

Retrieve a block by hash or height including raw block data on supported chains

Look up a transaction by id in either Blockbook-normalised or backend-native form

Read address state including balance, transactions, and history across supported chains

GET STARTED

Start building with Chain49 API API

Explore with Jentic

View OpenAPI Document

Use Cases

Patterns agents use Chain49 API API for, with concrete tasks.

★ Multi-Chain Wallet Backend

Power a wallet that supports multiple chains from a single API surface. The {blockchain} path parameter lets the same /v2/address, /v2/xpub, and /v2/utxo endpoints serve Bitcoin, Litecoin, Dogecoin, and other supported chains so the wallet does not need a per-chain integration. POST /{blockchain}/v2/sendtx broadcasts a signed transaction once the wallet has signed locally.

Call GET /{blockchain}/v2/xpub/{xpub} for the user's xpub on each supported chain and aggregate the total balance and address list

On-Chain Data Pipeline

Feed an analytics or indexer pipeline with block-level data without operating per-chain nodes. GET /{blockchain}/v2/block/{blockHashOrHeight} returns parsed block contents and GET /{blockchain}/v2/rawblock/{blockHashOrHeight} returns the raw block bytes for custom decoders. GET /{blockchain}/v2/mempool exposes pending transactions for real-time monitoring.

Call GET /{blockchain}/v2/block-index/{blockHeight} to resolve a height to a hash, then GET /{blockchain}/v2/rawblock/{blockHashOrHeight} and persist the result

Transaction Broadcast Service

Run a custodial or semi-custodial signer that builds and signs transactions in-house and uses Chain49 only for broadcast and confirmation tracking. POST /{blockchain}/v2/sendtx submits a signed hex, then GET /{blockchain}/v2/tx/{txId} polls the parsed transaction state, and GET /{blockchain}/v2/estimatefee/{confirmationTarget} feeds a dynamic fee policy.

Call POST /{blockchain}/v2/sendtx with the signed hex, then poll GET /{blockchain}/v2/tx/{txId} until the confirmations field exceeds 1

AI Agent Multi-Chain Lookup via Jentic

An agent receives a request like 'tell me the BTC and LTC balances at this xpub and the latest fee estimate for each chain'. Through Jentic, the agent searches for an xpub-balance operation and a fee-estimate operation, loads each input schema, and calls /v2/xpub and /v2/estimatefee with credentials drawn from the Jentic vault. The agent answers across both chains without per-chain wiring.

Use Jentic to search 'get xpub balance' and execute it for chain 'bitcoin' and chain 'litecoin', then search 'estimate transaction fee' for both

Key Endpoints

20 endpoints — chain49 is an extended trezor/blockbook-style multi-chain blockchain data api that exposes block, transaction, address, xpub, utxo, nft, and json-rpc endpoints across more than 10 chains out of the box and 50+ available on request.

METHOD

PATH

DESCRIPTION

GET

List supported blockchains

GET

/{blockchain}/v2/address/{address}

Read address state and transactions

GET

/{blockchain}/v2/xpub/{xpub}

Resolve xpub to derived addresses and balances

GET

/{blockchain}/v2/utxo/{addressOrXpub}

List unspent outputs for an address or xpub

GET

/{blockchain}/v2/tx/{txId}

Read a transaction by id

POST

/{blockchain}/v2/sendtx

Broadcast a signed transaction

GET

/{blockchain}/v2/estimatefee/{confirmationTarget}

Estimate fee for a confirmation target

POST

/{blockchain}/rpc

Pass-through JSON-RPC endpoint

GET

List supported blockchains

GET

/{blockchain}/v2/address/{address}

Read address state and transactions

GET

/{blockchain}/v2/xpub/{xpub}

Resolve xpub to derived addresses and balances

GET

/{blockchain}/v2/utxo/{addressOrXpub}

List unspent outputs for an address or xpub

GET

/{blockchain}/v2/tx/{txId}

Read a transaction by id

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Chain49 X-API-Key (or RapidAPI X-RapidAPI-Key/Host) values are stored encrypted in the Jentic vault and added to the request headers at execution time. Agents receive scoped access only — the raw keys never enter the agent's context window or prompt history.

Intent-based discovery

Agents search Jentic by intent (e.g., 'get an address balance' or 'broadcast a signed transaction') and Jentic returns the matching Chain49 operation with its input schema, so the agent calls the right endpoint with the correct {blockchain} segment without scraping the docs.

Time to first call

Direct Chain49 integration: half a day to wire dual-channel auth, multi-chain routing, and broadcast retries. Through Jentic: under 30 minutes — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

Alchemy API

EVM-focused blockchain infrastructure API with deep Ethereum tooling

Choose Alchemy when the workload is Ethereum or EVM L2s with rich tracing and webhook needs; choose Chain49 for Blockbook-style coverage across UTXO and EVM chains in one surface

Alternative

Tatum API

Multi-chain blockchain and wallet API across BTC, EVM, and many other chains

Choose Tatum when the agent needs higher-level wallet primitives across many chains; choose Chain49 for closer-to-node Blockbook semantics

Complementary

CoinGecko API

Crypto asset price and market cap data across thousands of coins

Use CoinGecko alongside Chain49 to add cross-asset price context to on-chain balance and transaction queries

FAQs

Specific to using Chain49 API API through Jentic.

What authentication does the Chain49 API use?

Chain49 supports two header-based modes. Direct calls to api.chain49.com use the X-API-Key header with a Chain49-issued key. Calls routed through RapidAPI use X-RapidAPI-Key plus X-RapidAPI-Host. Through Jentic, the appropriate keys live in the Jentic vault and are added at execution time so they never enter the agent's prompt or context window.

Which chains does the Chain49 API support?

The API exposes more than 10 chains out of the box and lists 50+ available on request. The exact set is dynamic — call GET / to read the current list of blockchain identifiers, then use those values as the {blockchain} path parameter on every other endpoint.

Can I broadcast a signed transaction with the Chain49 API?

Yes. POST /{blockchain}/v2/sendtx accepts a signed transaction hex in the body, and GET /{blockchain}/v2/sendtx/{hex} accepts the hex inline in the URL for compatibility with simple clients. Pair with GET /{blockchain}/v2/tx/{txId} to poll for confirmations.

What are the rate limits for the Chain49 API?

Limits are tied to your plan and to the channel you call through; RapidAPI plans publish their own quotas while direct keys are throttled per Chain49's commercial tiers. Watch for 429 responses with Retry-After headers and set client concurrency to match the lower of the two ceilings.

How do I read an xpub balance with the Chain49 API through Jentic?

Search Jentic for 'get an xpub balance', load the operation backed by GET /{blockchain}/v2/xpub/{xpub}, and execute it with the chain id and xpub. Jentic injects the X-API-Key header so the agent receives the typed xpub response with derived address counts and totals.

Does the Chain49 API support NFT metadata lookups?

Yes, on supported EVM chains. GET /{blockchain}/v2/nft/{nftContract}/{nftTokenId} returns the metadata Chain49 has indexed for that contract and token id, which is useful for wallet UIs that display owned NFTs without integrating a separate indexer.