[doc] GVA examples

doc/api/gva.md

@@ -13,6 +13,10 @@ See the playground of a GVA node:
 
 It is possible to send a batch of graphql requests. The size of a batch is limited to 5 requests (No limit for whitelisted ip).
 
+This is useful when the same query is repeated multiple times, and to allow the server to execute the queries in parallel.
+
+The playground does not support batch requests.
+
 ## Anti-spam limitations
 
 These limitations apply only to non-whitelisted IPs:
@@ -22,3 +26,68 @@ These limitations apply only to non-whitelisted IPs:
 * For paged requests, the pageSize parameter must be between 1 and 1000.
 
 [graphql]: https://graphql.org/
+
+## Examples
+
+### Send a transaction
+
+```
+mutation {
+  tx(
+    rawTx: "Raw transaction..."
+  ) {
+    hash
+  }
+}
+```
+
+### Get transactions
+
+```
+query {
+  txsHistoryBc(script: "78ZwwgpgdH5uLZLbThUQH7LKwPgjMunYfLiCfUCySkM8") {
+    both {
+      pageInfo {
+        hasNextPage
+        startCursor
+        endCursor
+      }
+      edges {
+        node {
+          inputs
+          outputs
+        }
+      }
+    }
+  }
+  txsHistoryMp(pubkey: "78ZwwgpgdH5uLZLbThUQH7LKwPgjMunYfLiCfUCySkM8") {
+    sending {
+      inputs
+      outputs
+    }
+    receiving {
+      inputs
+      outputs
+    }
+  }
+}
+```
+
+### Batch request
+
+```
+[
+  {"query": "{
+    idty(pubkey: \"D2meevcAHFTS2gQMvmRW5Hzi25jDdikk4nC4u1FkwRaU\") {
+      isMember
+      username
+    }
+  }"},
+  {"query": "{
+    idty(pubkey: \"Ds1z6Wd8hNTexBoo3LVG2oXLZN4dC9ZWxoWwnDbF1NEW\") {
+      isMember
+      username
+    }
+  }"}
+]
+```