NOWNodes API

Name: NOWNodes API
Brand: NOWNodes API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentDeveloper ToolsMonitoring ObservabilityapiKey12 EndpointsREST

For Agents

Read blockchain state and broadcast transactions across 100+ chains via JSON-RPC and BlockBook explorer endpoints, with single API-key access.

Install Jentic One Beta

Connect the NOWNodes API to your agent

Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the NOWNodes API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.

Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.

Step 1: Jentic One Host machine

# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh

Step 2: Agent machine

# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register       # connects your agent to your Jentic One instance

Jentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.

Capabilities

What an agent can do with NOWNodes API.

Forward JSON-RPC calls to full nodes for Bitcoin, Ethereum, Solana, and 100+ other chains

Query BlockBook explorers for blocks, transactions, and address details on UTXO chains

Look up balances, balance history, and UTXOs for an address or xpub

GET STARTED

Start building with NOWNodes API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI specification for NOWNodes API, keeping it validated and agent-ready. NOWNodes provides Blockchain-as-a-Service infrastructure with full-node RPC endpoints, BlockBook explorers, and WebSocket connections across 100+ chains including Bitcoin, Ethereum, Solana, Polygon, Arbitrum, Avalanche, and Cardano. The API exposes 12 endpoints covering JSON-RPC pass-through, BlockBook explorer queries, address and xpub lookups, UTXO retrieval, fee estimation, and transaction broadcast. It supports the operational tasks of reading blockchain state and submitting transactions without running and maintaining nodes.

Use Cases

Patterns agents use NOWNodes API for, with concrete tasks.

★ Multi-Chain Wallet Backend

A wallet application reads balances and transaction history across many chains without operating its own node fleet. NOWNodes provides JSON-RPC and BlockBook explorer endpoints behind a single API key, and the network path variable selects the chain per request, so adding support for a new chain is configuration rather than infrastructure work.

Fetch the balance for a Bitcoin address via the BlockBook /api/v2/address endpoint and the balance for an Ethereum address via the eth network JSON-RPC

Transaction Broadcasting and Fee Estimation

A wallet's send flow estimates the network fee for the desired confirmation target, then broadcasts the signed transaction. The /api/v2/estimatefee/{confirmationTarget} and /api/v2/sendtx/{hex} endpoints handle both steps, so the wallet does not need to maintain its own mempool and fee oracle.

Estimate the Bitcoin fee for a 6-block confirmation target and then broadcast a signed transaction hex via /api/v2/sendtx

Block Explorer Backend

A custom block explorer app uses NOWNodes' BlockBook endpoints to render block, transaction, address, and xpub pages without running BlockBook directly. Endpoints like /api/v2/block/{blockHashOrHeight} and /api/v2/tx/{txid} return the structured data the explorer needs, while /api/v2/balancehistory/{addressOrXpub} powers historical charts.

Render an address page by calling /api/v2/address/{address} for the summary, /api/v2/utxo/{addressOrXpub} for unspent outputs, and /api/v2/balancehistory for the chart

AI Agent Onchain Lookups

An AI agent answers user questions about onchain activity by calling NOWNodes through Jentic. The agent searches for the right RPC or BlockBook operation, loads the schema, and executes the call against the chain-specific subdomain rather than maintaining direct provider integrations.

Look up a transaction hash on Ethereum via JSON-RPC eth_getTransactionByHash and summarise the result for the user

Key Endpoints

12 endpoints — jentic publishes the only available openapi specification for nownodes api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

Send a JSON-RPC request to the selected network

GET

/api/v2/block/{blockHashOrHeight}

Get a block by hash or height

GET

/api/v2/tx/{txid}

Get transaction details

GET

/api/v2/address/{address}

Get address details

GET

/api/v2/utxo/{addressOrXpub}

Get UTXOs for an address or xpub

GET

/api/v2/sendtx/{hex}

Broadcast a signed transaction

GET

/api/v2/estimatefee/{confirmationTarget}

Estimate the transaction fee

POST

Send a JSON-RPC request to the selected network

GET

/api/v2/block/{blockHashOrHeight}

Get a block by hash or height

GET

/api/v2/tx/{txid}

Get transaction details

GET

/api/v2/address/{address}

Get address details

GET

/api/v2/utxo/{addressOrXpub}

Get UTXOs for an address or xpub

Why Jentic?

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

Credential isolation

NOWNodes api-key header values are stored encrypted in the Jentic vault. Agents receive scoped execution access — the raw API key never enters the agent's prompt or context.

Intent-based discovery

Agents search Jentic by intent (e.g. 'look up a Bitcoin address balance') and Jentic returns the matching JSON-RPC or BlockBook operation along with the network server variable to select the chain.

Time to first call

Direct NOWNodes integration: a few hours for per-chain endpoint and fee handling. Through Jentic: minutes — search, load schema, execute.

FAQs

Specific to using NOWNodes API through Jentic.

Why is there no official OpenAPI spec for NOWNodes API?

NOWNodes does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call NOWNodes API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the NOWNodes API use?

NOWNodes uses an API key passed in the api-key header. Through Jentic, the key is held in the vault and injected at execution time, so the agent never sees the raw value in its context.

Can I broadcast a signed transaction with the NOWNodes API?

Yes. GET /api/v2/sendtx/{hex} broadcasts a signed transaction hex to the chosen network's mempool. Pair it with /api/v2/estimatefee/{confirmationTarget} to set the right fee before signing.

What are the rate limits for the NOWNodes API?

The OpenAPI spec does not declare explicit rate limits. NOWNodes applies plan-based limits in production; check the response headers and the NOWNodes dashboard for current limits and upgrade tiers.

How do I query a specific blockchain through Jentic?

Search Jentic for 'look up address details on bitcoin'. Jentic returns the GET /api/v2/address/{address} operation with the network server variable, so the agent can target the right NOWNodes subdomain (for example btcbook.nownodes.io) for the chain in question.

Which chains does the NOWNodes API support?

The OpenAPI spec lists supported networks via server variable enums covering BTC, ETH (and ETH archive), BSC, SOL, LTC, DOGE, MATIC, ARB, OP, AVAX, ADA, XRP, DOT, TRX, ATOM, XLM, ALGO, NEAR, FTM, CELO, ONE, KLAY, ZEC, DASH, BCH, ETC, and BNB, with BlockBook covering the UTXO subset.