diff --git a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSchemasRouter.kt b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSchemasRouter.kt
index 0e23dee..85892ae 100644
--- a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSchemasRouter.kt
+++ b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSchemasRouter.kt
@@ -27,12 +27,12 @@ enum class FormSchemaIncludes(val value: String) : JsonApiIncludes {
 class FormSchemaRequestParameters(
     offset: Int = 0,
     limit: Int = 100,
-    filterOptions: List<FilterOption> = emptyList(),
+    filters: List<FilterOption> = emptyList(),
     includes: List<FormSchemaIncludes> = emptyList()
 ) : RequestParametersWithIncludes<FormSchemaIncludes>(
     offset = offset,
     limit = limit,
-    filterOptions = filterOptions,
+    filters = filters,
     includes = includes,
 )
 
diff --git a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionVersionsRouter.kt b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionVersionsRouter.kt
index 37e9797..a882ec2 100644
--- a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionVersionsRouter.kt
+++ b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionVersionsRouter.kt
@@ -34,12 +34,12 @@ enum class FormSubmissionVersionIncludes(val key: String) : JsonApiIncludes {
 class FormSubmissionVersionRequestParameters(
     offset: Int = 0,
     limit: Int = 100,
-    filterOptions: List<FilterOption> = emptyList(),
+    filters: List<FilterOption> = emptyList(),
     includes: List<FormSubmissionVersionIncludes> = emptyList()
 ) : RequestParametersWithIncludes<FormSubmissionVersionIncludes>(
     offset = offset,
     limit = limit,
-    filterOptions = filterOptions,
+    filters = filters,
     includes = includes,
 )
 
diff --git a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionsRouter.kt b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionsRouter.kt
index aba79d8..e0d967e 100644
--- a/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionsRouter.kt
+++ b/src/main/kotlin/com/ctrlhub/core/datacapture/FormSubmissionsRouter.kt
@@ -18,7 +18,7 @@ class FormSubmissionsRouter(httpClient: HttpClient) : Router(httpClient) {
     suspend fun all(organisationId: String, formId: String): PaginatedList<FormSubmission> {
         return fetchPaginatedJsonApiResources(
             "/v3/orgs/$organisationId/data-capture/forms/$formId/submissions",
-            queryParameters = emptyMap<String, String>(),
+            queryParameters = emptyMap(),
             FormSubmission::class.java,
             User::class.java,
             Form::class.java,
diff --git a/src/main/kotlin/com/ctrlhub/core/router/request/FilterExpression.kt b/src/main/kotlin/com/ctrlhub/core/router/request/FilterExpression.kt
new file mode 100644
index 0000000..7269d51
--- /dev/null
+++ b/src/main/kotlin/com/ctrlhub/core/router/request/FilterExpression.kt
@@ -0,0 +1,24 @@
+package com.ctrlhub.core.router.request
+
+sealed interface FilterOption {
+    fun format(): String
+}
+
+class FieldFilterExpression(val field: String, val values: List<String>) : FilterOption {
+    override fun format(): String {
+        val quoted = values.joinToString(",") { "'${it}'" }
+        return "${field}($quoted)"
+    }
+}
+
+class ValueFilterExpression(val value: String) : FilterOption {
+    override fun format(): String = value
+}
+
+class AndExpression(val parts: List<FilterOption>) : FilterOption {
+    override fun format(): String = "and(${parts.joinToString(",") { it.format() }})"
+}
+
+class OrExpression(val parts: List<FilterOption>) : FilterOption {
+    override fun format(): String = "or(${parts.joinToString(",") { it.format() }})"
+}
\ No newline at end of file
diff --git a/src/main/kotlin/com/ctrlhub/core/router/request/RequestParameters.kt b/src/main/kotlin/com/ctrlhub/core/router/request/RequestParameters.kt
index 6235114..a42f170 100644
--- a/src/main/kotlin/com/ctrlhub/core/router/request/RequestParameters.kt
+++ b/src/main/kotlin/com/ctrlhub/core/router/request/RequestParameters.kt
@@ -1,21 +1,24 @@
 package com.ctrlhub.core.router.request
 
-data class FilterOption(
-    val field: String,
-    val value: String
-)
-
 abstract class AbstractRequestParameters(
     val offset: Int? = null,
     val limit: Int? = null,
-    val filterOptions: List<FilterOption>
+    val filters: List<FilterOption> = emptyList()
 ) {
     open fun toMap(): Map<String, String> {
         val queryParams = mutableMapOf<String, String>()
         offset?.let { queryParams["offset"] = it.toString() }
         limit?.let { queryParams["limit"] = it.toString() }
 
-        filterOptions.forEach { queryParams["filter"] = "${it.field}('${it.value}')" }
+        val parts = mutableListOf<String>()
+
+        for (expr in filters) {
+            parts += expr.format()
+        }
+
+        if (parts.isNotEmpty()) {
+            queryParams["filter"] = parts.joinToString(",")
+        }
 
         return queryParams
     }
@@ -30,10 +33,11 @@ class RequestParameters(
 open class RequestParametersWithIncludes<TIncludes>(
     offset: Int? = null,
     limit: Int? = null,
-    filterOptions: List<FilterOption> = emptyList(),
+    filters: List<FilterOption> = emptyList(),
     val includes: List<TIncludes> = emptyList()
-) : AbstractRequestParameters(offset, limit, filterOptions) where TIncludes : JsonApiIncludes {
+) : AbstractRequestParameters(offset, limit, filters) where TIncludes : JsonApiIncludes {
 
+    @Suppress("unused")
     fun withIncludes(vararg includes: TIncludes): RequestParametersWithIncludes<TIncludes> {
         return copy(includes = this.includes + includes)
     }
@@ -53,7 +57,7 @@ open class RequestParametersWithIncludes<TIncludes>(
     }
 
     private fun copy(
-        filterOptions: List<FilterOption> = this.filterOptions,
-        includes: List<TIncludes> = this.includes
-    ) = RequestParametersWithIncludes(offset, limit, filterOptions, includes)
+        includes: List<TIncludes> = this.includes,
+        filters: List<FilterOption> = this.filters
+    ) = RequestParametersWithIncludes(offset, limit, filters, includes)
 }
diff --git a/src/test/kotlin/com/ctrlhub/core/router/request/RequestParametersFiltersTest.kt b/src/test/kotlin/com/ctrlhub/core/router/request/RequestParametersFiltersTest.kt
new file mode 100644
index 0000000..c283971
--- /dev/null
+++ b/src/test/kotlin/com/ctrlhub/core/router/request/RequestParametersFiltersTest.kt
@@ -0,0 +1,53 @@
+package com.ctrlhub.core.router.request
+
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+class RequestParametersFiltersTest {
+
+    @Test
+    fun `and of two field expressions formats correctly`() {
+        val expr = AndExpression(
+            listOf(
+                FieldFilterExpression("status", listOf("open")),
+                FieldFilterExpression("category", listOf("news"))
+            )
+        )
+
+        val params = RequestParameters(filterOptions = listOf(expr))
+        val map = params.toMap()
+
+        assertEquals("and(status('open'),category('news'))", map["filter"])
+    }
+
+    @Test
+    fun `and of functions formats correctly`() {
+        val expr = AndExpression(
+            listOf(
+                ValueFilterExpression("is_latest()"),
+                ValueFilterExpression("no_start()"),
+            )
+        )
+
+        val params = RequestParameters(filterOptions = listOf(expr))
+        val map = params.toMap()
+
+        assertEquals("and(is_latest(),no_start())", map["filter"])
+    }
+
+    @Test
+    fun `mixed and expression with field and function`() {
+        val expr = AndExpression(
+            listOf(
+                FieldFilterExpression("status", listOf("active")),
+                ValueFilterExpression("is_latest()")
+            )
+        )
+
+        val params = RequestParameters(filterOptions = listOf(expr))
+        val map = params.toMap()
+
+        assertEquals("and(status('active'),is_latest())", map["filter"])
+    }
+}
+