{"id":21290,"date":"2026-02-24T13:54:22","date_gmt":"2026-02-24T18:54:22","guid":{"rendered":"https:\/\/hedera.com\/?p=21290"},"modified":"2026-03-02T13:15:18","modified_gmt":"2026-03-02T18:15:18","slug":"upcoming-change-hiero-json-rpc-relay-default-configuration-updates-v0-77-0-20th-april-2026","status":"publish","type":"post","link":"https:\/\/hedera.com\/blog\/upcoming-change-hiero-json-rpc-relay-default-configuration-updates-v0-77-0-20th-april-2026\/","title":{"rendered":"Updates to the Hiero JSON-RPC Relay Default Configuration for Ethereum-Style Alignment | April 2026"},"content":{"rendered":"\n<p>The April 2026 release of the Hiero JSON-RPC Relay (v0.77.0), updates several default configuration values to better align the Relay\u2019s behavior with what developers expect from standard Ethereum JSON-RPC implementations.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>What\u2019s Changing<\/strong><\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><tbody><tr><td>Configuration<\/td><td>Current Default<\/td><td>Updated Default<\/td><\/tr><tr><td>ENABLE_TX_POOL<\/td><td>false<\/td><td>true<\/td><\/tr><tr><td>REDIS_ENABLED<\/td><td>true<\/td><td>false<\/td><\/tr><tr><td>USE_ASYNC_TX_PROCESSING<\/td><td>true<\/td><td>false<\/td><\/tr><tr><td>RATE_LIMIT_DISABLED<\/td><td>false<\/td><td>true<\/td><\/tr><tr><td>SUBSCRIPTIONS_ENABLED<\/td><td>false<\/td><td>true<\/td><\/tr><tr><td>HBAR_RATE_LIMIT_TINYBAR<\/td><td>25,000,000,000<\/td><td>0<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p>If you explicitly set these configuration values today, nothing changes for you. If you rely on defaults, your relay behavior will change after upgrading:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Transaction pool enabled by default<\/strong> (<em><code>ENABLE_TX_POOL=true<\/code><\/em>)<br>Expect increased in-memory tracking of pending transactions versus previous defaults.<br><\/li>\n\n\n\n<li><strong>WebSocket subscriptions enabled by default<\/strong> (<code><em>SUBSCRIPTIONS_ENABLED=true<\/em><\/code>)<br>Expect more long-lived connections and potentially higher resource usage depending on client behavior.<br><\/li>\n\n\n\n<li><strong>Redis is disabled by default<\/strong> (<code><em>REDIS_ENABLED=false<\/em><\/code>).<br>Redis-backed behavior is not used with defaults after upgrading unless this setting is explicitly configured.<br><\/li>\n\n\n\n<li><strong>Async transaction processing is disabled by default<\/strong> (<em><code>USE_ASYNC_TX_PROCESSING=false<\/code><\/em>).<br>Transaction processing runs synchronously by default, which shifts where load is handled and can change memory and CPU usage patterns compared to the previous default.<br><\/li>\n\n\n\n<li><strong>Relay internal rate limiting disabled by default<\/strong> (<code><em>RATE_LIMIT_DISABLED=true, HBAR_RATE_LIMIT_TINYBAR=0<\/em><\/code>)<br>Any rate limiting for the endpoint would be handled outside the Relay unless these settings are explicitly configured. This may result in additional spend on metered instances.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Why Is This Change Happening? \u00a0<\/strong><\/h3>\n\n\n\n<p>The relay is often used as the \u201cEthereum-like\u201d interface for tools such as wallets, indexers, explorers, and dApp backends. Many of these tools implicitly assume common Ethereum node behaviors.<\/p>\n\n\n\n<p>These default changes move the Relay closer to those expectations, while still allowing operators to override any setting.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>What You Need to Do<\/strong><\/h3>\n\n\n\n<p>Before you upgrade to the Hiero JSON-RPC Relay v0.77.0, decide whether you want the new defaults or to preserve the existing behavior.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Option A: Accept the new defaults<\/strong><\/h4>\n\n\n\n<p>No action needed.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong>Option B: Preserve existing behavior<\/strong><\/h4>\n\n\n\n<p>If you prefer to keep the existing behavior to avoid changes, you can explicitly set these values in your environment \/ Helm values \/ compose file:<\/p>\n\n\n\n<div class=\"hedera-code-window\" style=\"background-image:url('https:\/\/hedera.com\/wp-content\/uploads\/2025\/12\/CodeSnippetBackground-scaled.jpg');padding:24px;border-radius:8px;margin:24px 0\">\n  <!-- Hidden image so WP All Import downloads this background image into Media Library -->\n  <img decoding=\"async\" src=\"https:\/\/hedera.com\/wp-content\/uploads\/2025\/12\/CodeSnippetBackground-scaled.jpg\" alt=\"code window background\">\n<div class=\"code-window-header\">\n<div class=\"code-window-title\"><\/div>\n<div class=\"code-window-body\"><\/div>\n<\/div>\n<pre class=\"language-javascript\"><code class=\"language-javascript\"># Preserve prior defaults\nENABLE_TX_POOL=false\nREDIS_ENABLED=true\nUSE_ASYNC_TX_PROCESSING=true\nRATE_LIMIT_DISABLED=false\nSUBSCRIPTIONS_ENABLED=false\nHBAR_RATE_LIMIT_TINYBAR=25000000000\n<\/code><\/pre>\n<button class=\"hedera-copy-btn\">Copy<\/button><\/div>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Conclusion<\/strong><\/h3>\n\n\n\n<p>If you are currently using the Hiero JSON-RPC Relay, review the changes above and explicitly set any values you want to preserve or update before upgrading to v0.77.0.<br><br>If you have any questions or need guidance during this transition, please reach out on the Hedera <a href=\"http:\/\/hedera.com\/discord\">Discord<\/a> server or other official community channels.<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The April 2026 release of the Hiero JSON-RPC Relay (v0.77.0), updates several default configuration values to better align the Relay\u2019s behavior with what developers expect from standard Ethereum JSON-RPC implementations.<\/p>\n","protected":false},"author":1,"featured_media":21297,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"content-type":"","footnotes":""},"categories":[1],"tags":[],"ppma_author":[19],"class_list":["post-21290","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Updates to the Hiero JSON-RPC Relay Default Configuration for Ethereum-Style Alignment | April 2026 | Hedera<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/hedera.com\/blog\/upcoming-change-hiero-json-rpc-relay-default-configuration-updates-v0-77-0-20th-april-2026\/\" \/>\n<meta property=\"og:locale\" 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