feat(client): add demo mode via AXONFLOW_DEMO env var (#120)

* feat(client): add AXONFLOW_DEMO env var for demo mode

* feat(client): append random suffix to clientId in demo mode

* feat(community-saas): try.getaxonflow.com integration

- Rename AXONFLOW_DEMO → AXONFLOW_TRY
- URL: demo.getaxonflow.com → try.getaxonflow.com
- Remove client-side random suffix (server generates UUID tenant_id)
- Add AxonFlowTry.register() helper
- Checkpoint telemetry reports endpoint_type: "community-saas" in try mode

* chore: set release date 2026-04-09

* fix(changelog): remove entries not in this release

---------

Co-authored-by: Saurabh Jain <saurabhjain1592@gmail.com>

Author: gzak

CHANGELOG.md

@@ -5,17 +5,13 @@ All notable changes to the AxonFlow Java SDK will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [5.3.0] - Release Pending (2026-04-09)
+## [5.3.0] - 2026-04-09
 
-### Fixed
+### Added
 
-- **IPv6 endpoint classification.** `classifyEndpoint` now handles IPv6 private ranges and expanded loopback forms that previously fell through to `REMOTE`, matching the Python and Go SDK implementations:
-  - IPv6 ULA (`fc00::/7`, RFC 4193) → `private_network`
-  - IPv6 link-local (`fe80::/10`) → `private_network`
-  - Expanded IPv6 loopback (`0:0:0:0:0:0:0:1`, zero-padded forms) → `localhost`
-  - IPv6 unspecified (`::`) → `localhost` (symmetric with `0.0.0.0`)
-  - Public IPv6 addresses (`2001::/3` space) → `remote`
-- A new `expandIPv6(addr)` helper expands `::` compression into a full 8-hextet form for prefix comparison. Not a general-purpose parser — assumes input came from `URI.getHost()` after brackets are stripped.
+- `AXONFLOW_TRY=1` environment variable to connect to `try.getaxonflow.com` shared evaluation server
+- `AxonFlowTry.register()` helper for self-registering a tenant
+- Checkpoint telemetry reports `endpoint_type: "community-saas"` when try mode is active
 
 ---
 

src/main/java/com/getaxonflow/sdk/AxonFlowConfig.java

@@ -79,6 +79,9 @@ private static String detectSdkVersion() {
   /** Default endpoint URL. */
   public static final String DEFAULT_ENDPOINT = "http://localhost:8080";
 
+  /** Try mode endpoint URL. */
+  public static final String TRY_ENDPOINT = "https://try.getaxonflow.com";
+
   private final String endpoint;
   private final String clientId;
   private final String clientSecret;
@@ -90,9 +93,14 @@ private static String detectSdkVersion() {
   private final CacheConfig cacheConfig;
   private final String userAgent;
   private final Boolean telemetry;
+  private final boolean tryMode;
 
   private AxonFlowConfig(Builder builder) {
-    this.endpoint = normalizeUrl(builder.endpoint != null ? builder.endpoint : DEFAULT_ENDPOINT);
+    this.tryMode = "1".equals(System.getenv("AXONFLOW_TRY"));
+    this.endpoint =
+        this.tryMode
+            ? normalizeUrl(TRY_ENDPOINT)
+            : normalizeUrl(builder.endpoint != null ? builder.endpoint : DEFAULT_ENDPOINT);
     this.clientId = builder.clientId;
     this.clientSecret = builder.clientSecret;
     this.mode = builder.mode != null ? builder.mode : Mode.PRODUCTION;
@@ -112,6 +120,10 @@ private void validate() {
     if (endpoint == null || endpoint.isEmpty()) {
       throw new ConfigurationException("endpoint is required", "endpoint");
     }
+    if (tryMode && (clientId == null || clientId.isEmpty())) {
+      throw new ConfigurationException(
+          "clientId is required in try mode (AXONFLOW_TRY=1)", "clientId");
+    }
     // Credentials are optional for community/self-hosted deployments
     // Enterprise features require credentials (validated at method call time)
   }

src/main/java/com/getaxonflow/sdk/AxonFlowTry.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright 2025 AxonFlow
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.getaxonflow.sdk;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+/**
+ * Registration helper for try.getaxonflow.com shared evaluation server.
+ */
+public class AxonFlowTry {
+
+    public static final String TRY_ENDPOINT = "https://try.getaxonflow.com";
+
+    private static final ObjectMapper MAPPER = new ObjectMapper();
+    private static final HttpClient CLIENT = HttpClient.newBuilder()
+            .connectTimeout(Duration.ofSeconds(10))
+            .build();
+
+    /**
+     * Register for a free evaluation tenant. Store the secret securely — it is shown only once.
+     */
+    public static TryRegistration register() throws IOException, InterruptedException {
+        return register("", TRY_ENDPOINT);
+    }
+
+    /**
+     * Register with an optional label.
+     */
+    public static TryRegistration register(String label) throws IOException, InterruptedException {
+        return register(label, TRY_ENDPOINT);
+    }
+
+    /**
+     * Register with a custom endpoint (for local testing).
+     */
+    public static TryRegistration register(String label, String endpoint) throws IOException, InterruptedException {
+        String body = label != null && !label.isEmpty()
+                ? String.format("{\"label\":\"%s\"}", label)
+                : "{}";
+
+        HttpRequest request = HttpRequest.newBuilder()
+                .uri(URI.create(endpoint + "/api/v1/register"))
+                .header("Content-Type", "application/json")
+                .POST(HttpRequest.BodyPublishers.ofString(body))
+                .timeout(Duration.ofSeconds(10))
+                .build();
+
+        HttpResponse<String> response = CLIENT.send(request, HttpResponse.BodyHandlers.ofString());
+
+        if (response.statusCode() != 201) {
+            throw new IOException("Registration failed (" + response.statusCode() + "): " + response.body());
+        }
+
+        return MAPPER.readValue(response.body(), TryRegistration.class);
+    }
+
+    /**
+     * Registration response from try.getaxonflow.com.
+     */
+    public static class TryRegistration {
+        private String tenant_id;
+        private String secret;
+        private String secret_prefix;
+        private String expires_at;
+        private String endpoint;
+        private String note;
+
+        // Getters
+        public String getTenantId() { return tenant_id; }
+        public String getSecret() { return secret; }
+        public String getSecretPrefix() { return secret_prefix; }
+        public String getExpiresAt() { return expires_at; }
+        public String getEndpoint() { return endpoint; }
+        public String getNote() { return note; }
+
+        // Setters for Jackson
+        public void setTenant_id(String v) { this.tenant_id = v; }
+        public void setSecret(String v) { this.secret = v; }
+        public void setSecret_prefix(String v) { this.secret_prefix = v; }
+        public void setExpires_at(String v) { this.expires_at = v; }
+        public void setEndpoint(String v) { this.endpoint = v; }
+        public void setNote(String v) { this.note = v; }
+    }
+}

src/main/java/com/getaxonflow/sdk/telemetry/TelemetryReporter.java

@@ -231,6 +231,7 @@ public static final class EndpointType {
     public static final String LOCALHOST = "localhost";
     public static final String PRIVATE_NETWORK = "private_network";
     public static final String REMOTE = "remote";
+    public static final String COMMUNITY_SAAS = "community-saas";
     public static final String UNKNOWN = "unknown";
 
     private EndpointType() {}
@@ -248,6 +249,7 @@ private EndpointType() {}
    * <p>The raw URL is never sent — only the classification.
    */
   public static String classifyEndpoint(String url) {
+    if ("1".equals(System.getenv("AXONFLOW_TRY"))) return EndpointType.COMMUNITY_SAAS;
     if (url == null || url.isEmpty()) {
       return EndpointType.UNKNOWN;
     }