diff --git a/core/src/main/kotlin/io/github/nefilim/kjwt/Serializers.kt b/core/src/main/kotlin/io/github/nefilim/kjwt/Serializers.kt
index 3fe4256..ed4a168 100644
--- a/core/src/main/kotlin/io/github/nefilim/kjwt/Serializers.kt
+++ b/core/src/main/kotlin/io/github/nefilim/kjwt/Serializers.kt
@@ -9,6 +9,8 @@ import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
 
+class UnsupportedAlgorithmException(val alg: String): Exception("unsupported JWS algorithm: [$alg]")
+
 private val AllJWSAlgorithmToHeaderIDs = AllAlgorithms.associateBy { it.headerID }
 
 @OptIn(ExperimentalSerializationApi::class)
@@ -16,7 +18,8 @@ private val AllJWSAlgorithmToHeaderIDs = AllAlgorithms.associateBy { it.headerID
 object JWSAlgorithmSerializer: KSerializer<JWSAlgorithm> {
 
     override fun deserialize(decoder: Decoder): JWSAlgorithm {
-        return AllJWSAlgorithmToHeaderIDs[decoder.decodeString().trim().uppercase()] ?: throw IllegalArgumentException()
+        val alg = decoder.decodeString().trim().uppercase()
+        return AllJWSAlgorithmToHeaderIDs[alg] ?: throw UnsupportedAlgorithmException("unknown JWSAlgorithm: [$alg]")
     }
 
     override fun serialize(encoder: Encoder, value: JWSAlgorithm) {
diff --git a/core/src/test/kotlin/io/github/nefilim/kjwt/JWTSpec.kt b/core/src/test/kotlin/io/github/nefilim/kjwt/JWTSpec.kt
index a7345b4..8fbc173 100644
--- a/core/src/test/kotlin/io/github/nefilim/kjwt/JWTSpec.kt
+++ b/core/src/test/kotlin/io/github/nefilim/kjwt/JWTSpec.kt
@@ -30,12 +30,15 @@ import io.kotest.assertions.arrow.core.shouldBeSome
 import io.kotest.assertions.arrow.core.shouldBeValid
 import io.kotest.core.spec.style.WordSpec
 import io.kotest.matchers.shouldBe
+import mu.KotlinLogging
 import java.time.Instant
 import java.time.LocalDateTime
 import java.time.ZoneId
 import com.nimbusds.jwt.SignedJWT as NimbusSignedJWT
 
 class JWTSpec: WordSpec() {
+    private val logger = KotlinLogging.logger { }
+
     init {
         "JWT" should {
             "build JWT claim set" {
@@ -143,7 +146,7 @@ class JWTSpec: WordSpec() {
 
                     val signedJWT = rawJWT.sign(privateKey)
                     signedJWT.shouldBeRight().also {
-                        println(it.rendered)
+                        logger.info { it.rendered }
                         NimbusSignedJWT.parse(it.rendered).verify(ECDSAVerifier(publicKey)) shouldBe true
                         verifySignature(it.rendered, publicKey, pair.second).shouldBeRight() shouldBe it.jwt
                     }
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 54734f5..a13b38d 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,6 +1,6 @@
 [versions]
-kotlin = "1.6.10"
-kotlinXCoroutines = "1.6.0"
+kotlin = "1.6.21"
+kotlinXCoroutines = "1.6.1"
 kotlinXSerialization = "1.3.2"
 
 # third party
diff --git a/jwks/build.gradle.kts b/jwks/build.gradle.kts
index 614cdee..4bb2f39 100644
--- a/jwks/build.gradle.kts
+++ b/jwks/build.gradle.kts
@@ -12,6 +12,7 @@ dependencies {
         platform(libs.arrow.stack),
         libs.arrow.core,
         libs.kotlin.reflect,
+        libs.kotlinLogging,
         libs.kotlinx.coroutines.core,
         libs.kotlinx.serialization.json,
     ).map {
@@ -22,7 +23,6 @@ dependencies {
         libs.kotest.runner,
         libs.kotest.assertions.core,
         libs.kotest.assertions.arrow,
-        libs.kotlinLogging,
         libs.logbackClassic,
     ).map {
         testImplementation(it)
diff --git a/jwks/src/main/kotlin/io/github/nefilim/kjwt/jwks/JWKS.kt b/jwks/src/main/kotlin/io/github/nefilim/kjwt/jwks/JWKS.kt
index b9752e4..8b04be2 100644
--- a/jwks/src/main/kotlin/io/github/nefilim/kjwt/jwks/JWKS.kt
+++ b/jwks/src/main/kotlin/io/github/nefilim/kjwt/jwks/JWKS.kt
@@ -1,16 +1,8 @@
 package io.github.nefilim.kjwt.jwks
 
-import arrow.core.Either
+import arrow.core.*
 import arrow.core.computations.either
-import arrow.core.flatMap
-import arrow.core.left
-import arrow.core.right
-import arrow.core.sequenceEither
-import io.github.nefilim.kjwt.JWSAlgorithm
-import io.github.nefilim.kjwt.JWSAlgorithmSerializer
-import io.github.nefilim.kjwt.JWSECDSAAlgorithm
-import io.github.nefilim.kjwt.JWSRSAAlgorithm
-import io.github.nefilim.kjwt.JWTKeyID
+import io.github.nefilim.kjwt.*
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.currentCoroutineContext
@@ -24,10 +16,14 @@ import kotlinx.coroutines.flow.onCompletion
 import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.withContext
-import kotlinx.serialization.PolymorphicSerializer
-import kotlinx.serialization.SerialName
-import kotlinx.serialization.Serializable
+import kotlinx.serialization.*
+import kotlinx.serialization.builtins.ListSerializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonDecoder
+import kotlinx.serialization.json.jsonArray
 import java.math.BigInteger
 import java.net.URL
 import java.security.AlgorithmParameters
@@ -48,6 +44,9 @@ import kotlin.time.Duration.Companion.minutes
 import kotlin.time.Duration.Companion.seconds
 import kotlin.time.DurationUnit
 import kotlin.time.ExperimentalTime
+import mu.KotlinLogging
+
+private val logger = KotlinLogging.logger {  }
 
 @Serializable
 data class JWK<T: JWSAlgorithm>(
@@ -139,10 +138,38 @@ data class JWK<T: JWSAlgorithm>(
 }
 
 @Serializable
-data class JWKS<T: JWSAlgorithm>(
-    val keys: List<JWK<T>>
+data class JWKS(
+    @Serializable(JWKListSerializer::class) val keys: List<JWK<JWSAlgorithm>>
 )
 
+object JWKListSerializer: KSerializer<List<JWK<JWSAlgorithm>>> {
+    override fun deserialize(decoder: Decoder): List<JWK<JWSAlgorithm>> {
+        return with(decoder as JsonDecoder) {
+            decodeJsonElement().jsonArray.mapNotNull {
+                try {
+                    json.decodeFromJsonElement(JWK.serializer(PolymorphicSerializer(JWSAlgorithm::class)), it)
+                } catch (e: Exception) {
+                    when (e) {
+                        is SerializationException, is UnsupportedAlgorithmException -> {
+                            logger.warn { "ignoring JWK with deserialization problem $e " }
+                            null
+                        }
+                        else ->
+                            throw e
+                    }
+                }
+            }
+        }
+    }
+
+    private val listSerializer = ListSerializer(JWK.serializer(PolymorphicSerializer(JWSAlgorithm::class)))
+    override val descriptor: SerialDescriptor = listSerializer.descriptor
+
+    override fun serialize(encoder: Encoder, value: List<JWK<JWSAlgorithm>>) {
+        listSerializer.serialize(encoder, value)
+    }
+}
+
 sealed interface JWKError {
     object AlgorithmKeyMismatch: JWKError
     data class InvalidKey(val cause: Throwable): JWKError
@@ -207,7 +234,9 @@ object WellKnownJWKSProvider {
         either {
             val json = jwksJSONProvider(context, coroutineContext).bind()
             val jwks = Either.catch {
-                WellKnownJWKSProvider.json.decodeFromString(JWKS.serializer(PolymorphicSerializer(JWSAlgorithm::class)), json)
+//                WellKnownJWKSProvider.json.decodeFromString(JWKS.serializer(PolymorphicSerializer(JWSAlgorithm::class)), json)
+                WellKnownJWKSProvider.json.decodeFromString(JWKS.serializer(), json)
+//                WellKnownJWKSProvider.json.decodeFromString(JWKListSerializer, json)
             }.mapLeft { JWKError.Exceptionally(it) }.bind()
             jwks.keys.map { jwk -> jwk.build<P>().map { jwk.keyID to it } }.sequenceEither().bind().toMap()
         }
diff --git a/jwks/src/test/kotlin/io/github/nefilim/kjwt/jwks/JWKSpec.kt b/jwks/src/test/kotlin/io/github/nefilim/kjwt/jwks/JWKSpec.kt
index d8b29cd..21626d9 100644
--- a/jwks/src/test/kotlin/io/github/nefilim/kjwt/jwks/JWKSpec.kt
+++ b/jwks/src/test/kotlin/io/github/nefilim/kjwt/jwks/JWKSpec.kt
@@ -83,6 +83,9 @@ class JWKSSpec: WordSpec() {
                     }
                 })
             }
+            "gracefully handle unsupported algorithms" {
+                WellKnownJWKSProvider.json.decodeFromString(JWKS.serializer(), UnsupportedAlgorithmInJWK).keys.size shouldBe 2
+            }
         }
         "CachedJWKS" should {
             "refresh cache" {
@@ -92,7 +95,7 @@ class JWKSSpec: WordSpec() {
                     repeat(3) {
                         this().shouldBeRight()
                         this.getKey(keyID).shouldBeRight().shouldBeInstanceOf<RSAPublicKey>().also {
-                            println("got key: $it")
+                            logger.debug { "got key: $it" }
                             it shouldNotBe (previousKey)
                             previousKey = it
                         }
@@ -142,4 +145,47 @@ val RSAJWK = """
             "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"
         ]
     }
+""".trimIndent()
+
+
+val UnsupportedAlgorithmInJWK = """
+{
+"keys": [
+{
+"kid": "5NVqLy00rEUpMYV7evCXdQuIZ4zEgId-5LfM470iBpU",
+"kty": "RSA",
+"alg": "RSA-OAEP",
+"use": "enc",
+"n": "gYRpL9-iFMgo2yb7kS0T9h3kxfeeWYfpHgeKgo2BBgvE6cQ2lJ9ltb0YJg9f6cGLLhyZTyiM_eDMVWwiOLKUS6wAG4pYozNdUXGRovdfEjXz6EhCteIk0AImth1SoNsv5Vb_HwAkMj32lKBnByb-SSAbgVGSZ2MnZHIqOZUU4MLmlFBkhC6CmeDtXnfUlUkrixf8T-EepizJphOCQWcfrzSoQQDRlZqvBYlIHIUHKPcoliolrL5xowYBRaymTjUs0-G8iaEJYzLt0cGdkt4Ni3Zb3F6EvvieiCFJUVVg-bDe_0Lj78YQFb2CqGqIFijdfDSeZgqxYbiq4Nh7lcB32Q",
+"e": "AQAB",
+"x5c": [
+"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"
+],
+"x5t": "Rph0qHDDb9K5EJE-GFPKheTa_88",
+"x5t#S256": "1RgKt1HZm5sM82NxqTb8Kv4OOflELieeLcWNZLf8msg"
+},
+{
+"kid": "xY5PjYZLe0YrI2T8_3-SouOTHC3TQjDHKLw15VQAL7M",
+"kty": "RSA",
+"alg": "RS256",
+"use": "sig",
+"n": "jr0Yu-Mwe8tuVP12KDydtsd2MfHT_dkCVhuaFZx_u7798IXGT9f_SUtzV4fmy2g5HIKqKrZ5C7aCAe6MzTwWBmmY2gzh2f4Yp3alMavyzVLBIoTnYC_Vx_NgAyYH3cZqt2O5hUz3MonKV8YQ1FpLgzvDIEA04tWi3dn3Ku3pr-ZHRwaRYZ9JGDJnj5fVM9Db8pjMpxLEb1YD0JSb8OGu4WwePHs2K_9vXJ9z3UKe1SFjMBhhvOnRxtawhm7DgS8CpPJBEhzlNE-VY4d0CasD42QUBXJJpS-r7VZjBBUD0oYYs_fsGyuIUOPvxRYLm8QODLSkIxP7R_KZ8k7djY4OBw",
+"e": "AQAB",
+"x5c": [
+"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"
+],
+"x5t": "89b8Q_tnyMA9D6M_H5HyY51hbYc",
+"x5t#S256": "w8sR66yFksSyqOJE9Aev6sX-stHbRaIyM1DhUe3zB_g"
+},
+{
+"kid": "or06hiTwV9hLyp9giNGVs853jhHhEMRBbeD39fphP6w",
+"kty": "EC",
+"alg": "ES256",
+"use": "sig",
+"crv": "P-256",
+"x": "y3jWqPjKVR_d-dzU-Zj5WEFClSd8uNKFew_MJ07HDTA",
+"y": "WEVEjjM59EPhwCdI_X80Jzb8qJTV0Snlmnpgjqn2Y-o"
+}
+]
+}    
 """.trimIndent()
\ No newline at end of file