GreptimeDB vs TDengine

GreptimeDB is an open-source observability database for storing and querying metrics, logs, and traces through a columnar engine and shared SQL layer. It targets append-heavy, time-indexed workloads such as observability and IoT data, rather than general-purpose transactional database work. Users can query signal tables with SQL and metrics with PromQL. Ingestion options include Prometheus Remote Write, OpenTelemetry OTLP/HTTP, Loki Push API, Elasticsearch Bulk API, InfluxDB Line Protocol, MySQL, PostgreSQL, gRPC, and HTTP. Documented integrations include Prometheus, Grafana, Kafka, Apache Flink, Apache Spark, Telegraf, EMQX, and Fluent Bit. It can run standalone or as a horizontally scalable cluster, with Helm charts, Docker images, and binaries for macOS, Linux, Windows, and Android ARM64. The open-source edition lists username/password authentication, user-level read/write access control, and TLS/SSL connections. Enterprise adds features including LDAP, fine-grained RBAC, audit logging, and encryption at rest. The fully managed Enterprise plan costs $290 a month. Open-source users receive community support through Slack and GitHub.

TDengine is an industrial data platform combining data ingestion, storage, analytics, modeling, visualization, and AI applications. Its two core components are TDengine TSDB and TDengine IDMP; TSDB is a distributed time-series database with built-in caching, stream processing, and data subscription. The platform connects to industrial sources including OPC, MQTT, and Kafka, and includes ETL for data cleaning and transformation. It offers a REST API described by OpenAPI, plus JDBC, ODBC, Kafka, MQTT, iframe embedding, and an Excel Add-In. Self-hosted deployments can run at the edge, in containers or virtual machines, on local servers, or in public, private, and hybrid clouds. Managed TDengine Cloud is offered on Amazon Web Services, Microsoft Azure, and Google Cloud Platform. TDengine TSDB-OSS is open source under AGPL and includes clustering. The self-hosted Free Tier covers up to 5,000 tags. Listed plans include Starter at $970 a month, a 7,500-tag self-hosted annual license at $12,500 a year, and a 7,500-tag self-hosted perpetual license at $31,250 as a one-time purchase.