redb 4.0 delivers a coordinated major release across the entire ecosystem, updating redb.Core, redb.Route, redb.Tsak and redb.Identity in a single 4.0.0 version. Seventy-six NuGet packages, seven container images in GHCR and archives for Windows and Linux are now published. The Pro edition remains free and does not require a license key on the entire 4.x line.
redb.Route receives ten new packages and a substantial engine redesign. Declarative routes can now be defined in .route.xml files using the new redb.Route.Xml package and loaded into the same fluent DSL used for C# routes. The redb.Route.TestKit allows testing without brokers or route modifications through AdviceRoute, MockEndpoints and NotifyBuilder. Additional packages provide Scriban and Liquid templates, CSV, Protobuf, Avro and YAML data formats, JSONata transformations, in-memory or distributed caching, and XPath 2.0 support.
The routing engine now uses a single expression language and compiler for conditions, values and templates. New functions include stats, format, uuid and the modulo operator. The bean component allows custom objects to be used as endpoints with dependency injection. REST DSL, OpenAPI 3.0.3 generation, OpenTelemetry metrics inside routes and removal of Newtonsoft.Json in favour of System.Text.Json are also included.
Hosting improvements cover concurrent request limits with 429 responses, automatic consumer scaling for RabbitMQ, AMQP 1.0, IBM MQ, SQS and MQTT, WebSocket and SignalR support on the shared Kestrel host, and trusted proxy handling for X-Forwarded headers. Kafka consumers now preserve unprocessed records on partition revocation, and connectors for S3, Firebase and LLM providers received multiple stability and feature updates.
redb.Core introduces lazy references that load only on first access to Props when EnableLazyReferences is active, and unique keys via the new ValueUnique mechanism and [RedbUnique] attribute. Unique constraints are enforced by database indexes for scalars, nested objects, collections and entire subtrees. Schema upgrades are applied at startup with typed exceptions when rights are insufficient. CancellationToken support, save interceptors, per-request isolation levels and maintenance operations such as AnalyzeAsync are now available across PostgreSQL, MSSQL and SQLite.
redb.Tsak cluster coordination now relies on unique database keys from redb.Core. XML-only modules can be loaded and reloaded at runtime. The dashboard distinguishes load shedding from idle routes, Audit and Dead-letter pages are functional on PostgreSQL, and trusted proxy configuration is exposed for API throttling.
redb.Identity adds a WS-Trust SOAP facade supporting Issue, Validate, Cancel and Renew operations. Access tokens now include audience claims according to RFC 9068. The administrative console has been rebuilt with full pages instead of dialogs, and DPoP support behind TLS-terminating proxies has been improved.
Several security issues were addressed. Internal headers are now stripped on all three identity facades. Consent pages validate signed tickets and Origin headers. Introspection responses are restricted to token audiences. Dashboard pages require authentication with role-based access. Module signatures are verified on every load path, and the default password hasher is now bcrypt.
Clusters must be fully stopped before upgrading because mixed versions are unsupported. Large databases require a maintenance window for schema changes performed under exclusive locks. Full change logs are published at redb.ru/releases.


