canonical: https://jentic.com/apis/cryptoapis.io/cryptoapis

# Crypto APIs Blockchain REST API

Crypto APIs provides unified blockchain REST endpoints across Bitcoin, Ethereum, Litecoin, and other major chains so developers do not have to run their own nodes. The catalogued slice exposes blockchain data lookups for addresses, transactions, and blocks, wallet-as-a-service address generation, transaction confirmation callbacks, and an address validation tool. Authentication is by x-api-key header, and the platform is well suited for back-office reconciliation and on-chain monitoring rather than user-facing wallets.

## For AI agents

Look up balances, transactions, and blocks across multiple blockchains, generate wallet addresses, and subscribe to on-chain confirmation callbacks.

## Scope

Does not handle private key custody for end users, on-ramp fiat conversion, or smart contract deployment - use for blockchain data lookups, wallet-as-a-service address generation, and confirmation webhooks only.

## Capabilities

- Look up the balance and transaction history for an address on a specific blockchain and network
- Retrieve a transaction by hash including its inputs, outputs, fee, and confirmation count
- Fetch a block by height or hash and inspect every transaction it contains
- Generate a new receiving address inside a wallet-as-a-service wallet for a specific blockchain
- Subscribe to address-level callbacks that fire when an incoming transaction confirms
- Validate that a string is a syntactically and checksum-valid address for a given chain before sending funds

## Use cases

### Multi-Chain Deposit Reconciliation

Reconcile customer deposits across Bitcoin, Ethereum, and Litecoin by querying address transactions through a single API instead of running a node per chain. The agent fetches each customer's deposit address transactions, matches confirmed amounts against expected payments, and updates the ledger. This replaces bespoke node infrastructure with a hosted REST surface that scales with traffic.

Example prompt: Call GET `/blockchain-data/{blockchain}/{network}/addresses/{address}/transactions` for each customer address and reconcile confirmed transactions against expected payments.

### Address Generation for Wallet-as-a-Service

Run a custodial product that issues a fresh receiving address per customer without managing private keys directly. Crypto APIs' wallet-as-a-service generates addresses inside a managed wallet and ties them back to the parent wallet for withdrawal aggregation. The same API surface works across blockchains so onboarding a new chain only changes the path parameter.

Example prompt: Call POST `/wallet-as-a-service/wallets/{walletId}/{blockchain}/{network}/addresses` to generate a fresh deposit address for a customer.

### On-Chain Confirmation Webhooks

Trigger backend workflows the moment an incoming transaction confirms instead of polling the chain. Crypto APIs' address-coins-transactions-confirmed subscription sends a callback with the transaction hash and confirmation count, letting an order processor mark a payment received in near real time. Combined with address validation, this prevents writing funds to malformed destination strings.

Example prompt: Call POST `/blockchain-events/{blockchain}/{network}/subscriptions/address-coins-transactions-confirmed` with the deposit address and a callback URL.

### AI Agent Blockchain Lookups

Agents answering 'what is the balance of this wallet' or 'did this transaction confirm' need a stable, schema'd blockchain backend rather than scraping block explorers. Through Jentic the agent searches for the relevant Crypto APIs operation, loads its schema, and executes against the x-api-key stored in the vault. Latency is predictable because the API is hosted, not run on commodity nodes.

Example prompt: Search Jentic for 'look up a blockchain transaction', load the Crypto APIs operation, and execute it with blockchain=bitcoin, network=mainnet, and the transaction hash.

## Key endpoints

| Method | Path | Description |
| --- | --- | --- |
| GET | `/blockchain-data/{blockchain}/{network}/addresses/{address}` | Get address balance and metadata |
| GET | `/blockchain-data/{blockchain}/{network}/addresses/{address}/transactions` | List transactions for an address |
| GET | `/blockchain-data/{blockchain}/{network}/transactions/{transactionId}` | Get a transaction by hash |
| GET | `/blockchain-data/{blockchain}/{network}/blocks/{blockId}` | Get a block by height or hash |
| GET | `/blockchain-data/{blockchain}/{network}/blocks/last` | Get the latest block |
| POST | `/wallet-as-a-service/wallets/{walletId}/{blockchain}/{network}/addresses` | Generate a wallet receiving address |
| POST | `/blockchain-events/{blockchain}/{network}/subscriptions/address-coins-transactions-confirmed` | Subscribe to confirmation callbacks |
| GET | `/blockchain-tools/{blockchain}/{network}/addresses/validate` | Validate an address string |

## Key resources

- **Addresses** — Look up balances and transactions for an address on a specific chain and network
- **Transactions** — Retrieve transactions by hash with inputs, outputs, and fees
- **Blocks** — Inspect blocks by height or hash including their transactions
- **HD Wallets** — Generate addresses inside managed wallet-as-a-service wallets
- **Callbacks** — Subscribe to confirmation events for an address
- **Tools** — Validate address strings before sending funds

## Why Jentic

- **Setup:** Wiring the Crypto APIs Blockchain REST API by hand means setting its x-api-key header and threading blockchain-, network-, and address-scoped lookup, wallet, and subscription calls yourself. Through Jentic you install once, import the Crypto APIs Blockchain REST API from the API Directory, store the API key once, and your agent calls it.
- **Permission scoping:** Crypto APIs puts the blockchain, network, and address in the URL path (`/blockchain-data/{blockchain}/{network}/addresses/{address}`), so a rule can pin your agent to one blockchain and network for reads. You choose the operations it may call, so generating wallet addresses or creating confirmation subscriptions is not included unless you add it.
- **Credential handling:** Your Crypto APIs x-api-key is stored once, encrypted, by your own Jentic One instance and injected into the x-api-key header at execution time. It never enters the agent's prompt, logs, or context.
- **Discovery method:** Agents search Jentic by intent such as 'look up an address balance' or 'subscribe to a blockchain confirmation', and Jentic returns the matching Crypto APIs operation with its input schema so the agent calls the right endpoint without browsing the reference docs.

## Related APIs

- **Blockchain.com API** — Bitcoin-focused blockchain data and wallet API
- **Alchemy API** — Ethereum and L2-focused infrastructure with enhanced JSON-RPC
- **CryptAPI** — Non-custodial payment forwarding for accepting crypto

## FAQ

### What authentication does the Crypto APIs Blockchain REST API use?

Crypto APIs uses an x-api-key header. Every request must include the header with a key issued from the Crypto APIs dashboard. Through Jentic the key is sourced from the vault and never reaches the agent context.

### Can I look up an Ethereum balance with the Crypto APIs Blockchain REST API?

Yes. Call GET `/blockchain-data/{blockchain}/{network}/addresses/{address}` with blockchain=ethereum and network=mainnet to retrieve the address balance and metadata. The same path supports Bitcoin and other blockchains by changing the path parameter.

### What are the rate limits for the Crypto APIs Blockchain REST API?

Limits depend on the Crypto APIs plan tier and reset monthly rather than per second. The dashboard reports remaining calls per plan; treat the API as request-budgeted rather than rate-bursted.

### How do I subscribe to a confirmation callback through Jentic?

Search Jentic for 'subscribe to a blockchain confirmation' and execute the loaded operation against POST `/blockchain-events/{blockchain}/{network}/subscriptions/address-coins-transactions-confirmed` with the address and callback URL.

### Is the Crypto APIs Blockchain REST API free?

Crypto APIs offers a free tier with a monthly request quota and paid tiers above that. Pricing is published at https://cryptoapis.io/pricing.

### How do I validate a Bitcoin address before sending funds?

Call GET `/blockchain-tools/{blockchain}/{network}/addresses/validate` with blockchain=bitcoin to verify the address is syntactically valid and correctly checksummed for the target network.

### Can I limit what my agent is allowed to do with the Crypto APIs Blockchain REST API?

Yes. Jentic One is self-hosted, so your own rules decide which Crypto APIs operations and credentials the agent may use. Because the blockchain, network, and address sit in the URL path, such as `/blockchain-data/{blockchain}/{network}/addresses/{address}`, you can pin the agent to a single chain and network for read-only lookups of balances, transactions, and blocks. You choose the operations it may call, so generating wallet-as-a-service addresses or creating confirmation subscriptions is excluded unless you explicitly allow it.