Best Practices

Use pagination instead of over-fetching

Blockscout REST endpoints use keyset pagination. By default a response returns the first 50 results. When a response includes next_page_params, copy that object and append its fields to your next request rather than paging through with an offset:

{
  "items": [ ... ],
  "next_page_params": {
    "block_number": 18678766,
    "index": 119,
    "items_count": 50
  }
}

curl "https://api.blockscout.com/1/api/v2/addresses/0xYourAddress/transactions?block_number=18678766&index=119&items_count=50&apikey=<your_pro_api_key>"

Only request more pages than you need if you actually plan to use the data — each page is a separate call against your credit allowance.

Know your credit costs before you build

Every call consumes credits, and the cost varies by endpoint — the default is 20 credits, but a few heavier endpoints (transaction summaries, raw traces, coin balance history) cost more. See Rate Limits for the full table. If you’re building something that polls frequently, budget for the endpoint’s actual cost, not the 20-credit default.

Filter scam tokens by default — know when not to

Token endpoints filter known scam airdrops out of results by default, which is usually what you want for a wallet UI or portfolio tracker. If you need the unfiltered list — for a dispute, an audit, or your own scoring layer — pass the show-scam-tokens header on the relevant token-transfer call.

One key, every chain — don’t provision per network

The PRO API scopes every request by chain_id, not by base URL or key. The same key that works on Ethereum works on Base, Arbitrum, Optimism, and every other supported chain — there’s no need to request separate credentials per network the way some other explorers require.

Prefer REST over RPC-style calls for richer data

The Etherscan-compatible module/action route is the easiest migration path if you’re already using it, but Blockscout’s REST API (/api/v2/...) returns more — decoded input data, human-readable transaction summaries, NFT metadata, and contract state — from the same underlying data with no extra indexing work on your side. If you’re building new, start with REST.

Combine feeds for a complete picture

No single endpoint gives you a wallet’s full onchain footprint. A typical active address has top-level transactions, internal value movements (from DEX or bridge interactions), and token transfers, all as separate feeds:

Feed	Endpoint
Top-level transactions	`GET /{chain_id}/api/v2/addresses/{address}/transactions`
Internal transactions	`GET /{chain_id}/api/v2/addresses/{address}/internal-transactions`
Token transfers	`GET /{chain_id}/api/v2/addresses/{address}/token-transfers`

Join by transaction hash and deduplicate when combining them — see Wallet History and Tax Calculator for worked examples.

Watch the response headers, not just the response body

Every PRO API response includes headers that tell you exactly where you stand, so you don’t have to guess:

x-credits-remaining — credits left in your current period
x-ratelimit-limit — your plan’s RPS ceiling
x-ratelimit-remaining — RPS headroom left in the current window

If x-credits-remaining isn’t decreasing, your key isn’t authenticating — check it before assuming the data is wrong.

Historical pricing needs an external feed

The PRO API returns current exchange rates, but not historical ones. If you need the USD value of an asset at the moment of a past transaction (for tax or accounting workflows), pair the block timestamp on each row with an external pricing feed — CoinGecko, Pyth, or your own oracle.

Blockscout APIs

PRO API Endpoints

Additional Service APIs

Know your credit costs before you build

Filter scam tokens by default — know when not to

One key, every chain — don’t provision per network

Prefer REST over RPC-style calls for richer data

Combine feeds for a complete picture

Watch the response headers, not just the response body

Historical pricing needs an external feed

​Use pagination instead of over-fetching

​Know your credit costs before you build

​Filter scam tokens by default — know when not to

​One key, every chain — don’t provision per network

​Prefer REST over RPC-style calls for richer data

​Combine feeds for a complete picture

​Watch the response headers, not just the response body

​Historical pricing needs an external feed

Use pagination instead of over-fetching

Know your credit costs before you build

Filter scam tokens by default — know when not to

One key, every chain — don’t provision per network

Prefer REST over RPC-style calls for richer data

Combine feeds for a complete picture

Watch the response headers, not just the response body

Historical pricing needs an external feed