Title: Engineering Alert: Handling Breaking Changes in Etherscan APIs (July 2026)

For years, Etherscan has been the backbone of Ethereum data indexing. However, a significant shift is coming. Effective July 1, 2026, Etherscan is implementing breaking changes to its Free Tier API constraints.
If your dApp, indexer, or analytics tool relies on Etherscan, you need to refactor your data-fetching logic now to avoid service disruptions.
1. The Pagination Crunch: 10k to 1k Record Limit
The most critical update is the reduction of the maximum records returned per request. The limit is dropping from 10,000 to 1,000 records for Free tier users.
Technical Impact:
Standard fetch requests for high-velocity addresses (like CEX hot wallets or popular DeFi protocols) will now return incomplete datasets if your offset was previously set to any value above 1,000.
Affected Endpoints:
Account Module: txlist, txlistinternal, tokentx, tokennfttx, token1155tx.
Logs & Others: getLogs, getWithdrawals, and Token Holder Lists.
Action Required: Implement Aggressive Pagination
You must refactor your fetch loops.
2. Endpoint Migration: Block Range Internal Tx to Pro Tier
The endpoint Get Internal Transactions by Block Range is moving behind a Pro Plan paywall.
Technical Impact:
Requests to this endpoint using a Free Tier API key will return a 403 Forbidden or a specific tier-limit error starting July 2026.
Mitigation Strategies:
Tier Upgrade: The most straightforward fix for enterprise-grade applications.
Granular Querying: Instead of querying by block range, you may need to fetch internal transactions by specific Transaction Hash (txhash), though this increases the number of API calls significantly and may trigger rate limits.
3. Managing Rate Limits (Throttling)
The Free Tier still maintains a limit of 5 requests per second (RPS). Because you now need 10 requests to get the data you previously got in one, you are 10x more likely to hit 429 Too Many Requests errors.
Recommendation:
Implement an Exponential Backoff or a request queue manager (like p-throttle or bottleneck) to ensure your new multi-page fetching logic doesn't crash your API key.
Developer Checklist for Migration:
Audit: Search your codebase for any Etherscan API calls where offset > 1000.
Refactor: Implement recursive or loop-based pagination using the page parameter.
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Tags: #Ethereum #Blockchain #API