From 10f875fb06e600106cba9d62d867da6eda474ae5 Mon Sep 17 00:00:00 2001
From: John Mitsch <john@quicknode.com>
Date: Wed, 27 May 2026 10:50:11 -0400
Subject: [PATCH] fix(webhooks): send camelCase eventHashes in
 evmContractEvents template (DX-5346)
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The Webhooks API expects `eventHashes` (camelCase) in the
`evmContractEvents` templateArgs. `EvmContractEventsTemplate` had no
serde rename, so the field was serialized as `event_hashes` and the API
returned `500: Expected array for arg "eventHashes"` whether the field
was supplied or not — making the template effectively unusable.
---
 crates/core/src/webhooks/mod.rs     | 39 +++++++++++++++++++++++++++++
 crates/core/src/webhooks/webhook.rs |  4 +++
 2 files changed, 43 insertions(+)

diff --git a/crates/core/src/webhooks/mod.rs b/crates/core/src/webhooks/mod.rs
index 0bbd919..225fb79 100644
--- a/crates/core/src/webhooks/mod.rs
+++ b/crates/core/src/webhooks/mod.rs
@@ -740,6 +740,45 @@ mod tests {
             .unwrap();
     }
 
+    // Wire-inspection regression: the API expects `eventHashes` (camelCase)
+    // and returns 500 if it sees `event_hashes`. Confirm the field reaches the
+    // wire under the camelCase key.
+    #[tokio::test]
+    async fn create_webhook_from_template_wire_body_uses_camelcase_event_hashes() {
+        use wiremock::matchers::body_partial_json;
+        let server = MockServer::start().await;
+        Mock::given(method("POST"))
+            .and(path_regex("/webhooks/template/evmContractEvents"))
+            .and(body_partial_json(serde_json::json!({
+                "templateArgs": {
+                    "eventHashes": ["0xabcd"],
+                }
+            })))
+            .respond_with(ResponseTemplate::new(201).set_body_json(webhook_response_json()))
+            .mount(&server)
+            .await;
+        let sdk = make_sdk(format!("{}/", server.uri()));
+        let template_args = TemplateArgs::EvmContractEvents(EvmContractEventsTemplate {
+            contracts: vec!["0xa0b8".to_string()],
+            event_hashes: Some(vec!["0xabcd".to_string()]),
+        });
+        let params = CreateWebhookFromTemplateParams {
+            name: "test-webhook".to_string(),
+            network: "ethereum-mainnet".to_string(),
+            notification_email: None,
+            destination_attributes: WebhookDestinationAttributes {
+                url: "https://example.com/hook".to_string(),
+                security_token: None,
+                compression: None,
+            },
+            template_args,
+        };
+        sdk.webhooks
+            .create_webhook_from_template(&params)
+            .await
+            .unwrap();
+    }
+
     #[tokio::test]
     async fn update_webhook_template_api_error() {
         let server = MockServer::start().await;
diff --git a/crates/core/src/webhooks/webhook.rs b/crates/core/src/webhooks/webhook.rs
index 42eac0f..89cad36 100644
--- a/crates/core/src/webhooks/webhook.rs
+++ b/crates/core/src/webhooks/webhook.rs
@@ -99,6 +99,7 @@ impl EvmWalletFilterTemplate {
 #[cfg_attr(feature = "python", pyclass(get_all, set_all))]
 #[cfg_attr(feature = "node", napi(object))]
 #[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
 pub struct EvmContractEventsTemplate {
     /// Contract addresses to watch for events.
     pub contracts: Vec<String>,
@@ -547,6 +548,9 @@ mod template_args_tests {
         });
         let json = serde_json::to_string(&args).unwrap();
         assert!(json.contains(r#""templateId":"evmContractEvents""#));
+        // API expects camelCase `eventHashes` — snake_case is silently rejected with a 500.
+        assert!(json.contains(r#""eventHashes":["0x1234"]"#));
+        assert!(!json.contains("event_hashes"));
         let parsed: TemplateArgs = serde_json::from_str(&json).unwrap();
         assert!(matches!(parsed, TemplateArgs::EvmContractEvents(_)));
     }