--- title: Arize AX Alternative? Langfuse vs. Arize AI and Arize Phoenix for LLM Observability description: August 2026 comparison of Langfuse, Arize AX, and Arize Phoenix for LLM observability, evaluations, self-hosting, and pricing. tags: [comparison] --- # Langfuse vs. Arize AX / Arize Phoenix This guide outlines the key differences between **[Langfuse](/)**, **[Arize AX](https://arize.com/llm-observability/)**, and **[Arize Phoenix](https://phoenix.arize.com)** to help engineering teams choose the right LLM observability platform. Product facts below were checked against public Arize sources on August 13, 2026. In August 2026, Dynatrace [announced a definitive agreement to acquire Arize](https://www.dynatrace.com/news/press-release/dynatrace-to-acquire-arize/). As of publication, Arize AX and Phoenix remain available. This page compares the current products. **TL;DR:** - **Choose Langfuse** if you want [MIT-licensed](https://github.com/langfuse/langfuse) tracing and evaluation, [self-hosted](/self-hosting) or on Cloud, with usage-based Cloud pricing and no vendor lock-in. It is the open-source AI engineering platform with the most public adoption. - **Choose Phoenix** if you want an Elastic License 2.0, local-first platform for tracing, evaluations, datasets, experiments, and prompt management. It can run as one container (SQLite) or multi-instance deployments (PostgreSQL). - **Choose Arize AX** if you want Arize's managed production platform, listed PCI DSS 4.0 status, an Enterprise self-hosted option, and Enterprise Data Fabric access, which is currently waitlisted. Already on Phoenix? See [Migrate from Arize Phoenix to Langfuse](/resources/engineering/migrate-from-phoenix). Already on AX? See [Migrate from Arize AX to Langfuse](/resources/engineering/migrate-from-arize-ax). [Talk to us](/talk-to-us) if you want help with the move. - [Get started free](https://cloud.langfuse.com) - [Talk to us](/talk-to-us) ## Open Source & Distribution Langfuse is [MIT-licensed](https://github.com/langfuse/langfuse) across tracing, evaluations, prompt management, and experiments. [OSS self-hosting](/self-hosting) runs the same core product and ClickHouse architecture as Cloud, so you can move between Cloud and self-host, or off Langfuse, without rewriting the application layer. [Enterprise governance modules](/pricing-self-host) (audit logs, project-level RBAC, SCIM, protected labels, retention policies) need an Enterprise license when self-hosted. Arize ships two products. [Phoenix](https://docs.arize.com/phoenix) is source-available under the Elastic License 2.0 (not an OSI-approved open-source license) and self-hosts on SQLite or PostgreSQL. [Arize AX](https://arize.com/llm-observability/) is proprietary SaaS (self-hosting is an Enterprise option). Phoenix and AX do not share a storage engine: Phoenix uses Postgres/SQLite; AX Cloud uses [adb](https://arize.com/blog/introducing-adb-arizes-proprietary-olap-database). Dynatrace's [acquisition announcement](https://www.dynatrace.com/news/press-release/dynatrace-to-acquire-arize/) is an enterprise AI observability deal. It refers to Arize as "OSS-native" and highlights its open-source developer community, but it does not name Phoenix, and it does not state a license or a commitment that a standalone open-source product continues. For current Phoenix licensing and availability, see the [Phoenix license](https://github.com/Arize-ai/phoenix/blob/main/LICENSE) and [self-hosting documentation](https://docs.arize.com/phoenix/deployment). | Feature | Langfuse | Arize AX | | ------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **Model** | **[Open Source](https://github.com/langfuse/langfuse)** (MIT License) | **AX:** proprietary SaaS. **[Phoenix](https://github.com/arize-ai/phoenix):** Elastic License 2.0 (source-available) | | **GitHub Stars** | [![Langfuse GitHub stars](https://img.shields.io/github/stars/langfuse/langfuse?style=for-the-badge&label=%20&labelColor=black&color=orange)](https://github.com/langfuse/langfuse) | [![Phoenix GitHub stars (Phoenix)](https://img.shields.io/github/stars/arize-ai/phoenix?style=for-the-badge&label=%20&labelColor=black&color=grey)](https://github.com/arize-ai/phoenix) | | **PyPI Downloads** | [![Langfuse pypi downloads](https://img.shields.io/pypi/dm/langfuse?style=for-the-badge&label=%20&labelColor=black&color=orange)](https://pypi.org/project/langfuse/) | [![Phoenix pypi downloads (Phoenix)](https://img.shields.io/pypi/dm/arize-phoenix?style=for-the-badge&label=%20&labelColor=black&color=grey)](https://pypi.org/project/arize-phoenix) | | **npm Downloads** | [![Langfuse npm downloads](https://img.shields.io/npm/dm/@langfuse/tracing?style=for-the-badge&label=%20&labelColor=black&color=orange)](https://www.npmjs.com/package/@langfuse/tracing) | [![Phoenix npm downloads](https://img.shields.io/npm/dm/%40arizeai%2Fphoenix-client?style=for-the-badge&label=%20&labelColor=black&color=grey)](https://www.npmjs.com/package/@arizeai/phoenix-client) | | **Docker Pulls** | [![Langfuse Docker Pulls](https://img.shields.io/docker/pulls/langfuse/langfuse?style=for-the-badge&label=%20&labelColor=black&color=orange)](https://hub.docker.com/r/langfuse/langfuse) | [![Phoenix Docker Pulls (Phoenix)](https://img.shields.io/docker/pulls/arizephoenix/phoenix?style=for-the-badge&label=%20&labelColor=black&color=grey)](https://hub.docker.com/r/arizephoenix/phoenix) | | **Self-Hosting** | **[Free OSS](/self-hosting)**: same codebase and ClickHouse architecture as Cloud. Enterprise governance needs an [Enterprise license](/pricing-self-host). | **Phoenix:** [self-host](https://docs.arize.com/phoenix/deployment) on SQLite/Postgres. **AX:** [self-host on Enterprise](https://arize.com/pricing/). | ## Scalability & Performance Both tools are built for scale, but they use different architectural approaches. Langfuse is part of ClickHouse and leverages the speed of ClickHouse architecture, while Arize AX uses a proprietary database. | Feature | Langfuse | Arize AX | | ----------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | **Backend** | **[ClickHouse](https://clickhouse.com/)** ([acquired Langfuse](https://langfuse.com/blog/joining-clickhouse)): Optimized for high-throughput OLAP. | **[adb (Arize Database)](https://arize.com/blog/introducing-adb-arizes-proprietary-olap-database)**: Proprietary engine for agentic telemetry. | ## Integrations Both platforms ingest OpenTelemetry. Langfuse [maps OpenInference attributes](/integrations/native/opentelemetry) natively, so existing OpenInference instrumentors can keep running and export to Langfuse. | Feature | Langfuse | Arize AX / Phoenix | | ---------------- | --------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------- | | **Standard** | **[OpenTelemetry Native](/docs/observability/overview)**: Built on OTel standards. | **[OpenTelemetry compliant](https://arize.com/docs/ax/integrations/opentelemetry/overview)**: Built on OTel standards. | | **Integrations** | **[120+ integrations](/integrations)** plus OpenInference ingest via [OTLP](/integrations/other/openinference). | [OpenInference](https://github.com/Arize-ai/openinference) auto-instrumentation across popular frameworks. | ## Pricing Langfuse Cloud meters one unit (a trace, observation, or score) with no seat fees. Arize AX meters spans and ingested GB, with retention included per plan. Phoenix self-hosted has no platform usage fee; you run the infrastructure. Figures below are from [Arize pricing](https://arize.com/pricing/) and [Langfuse pricing](/pricing) as of August 2026. | Feature | Langfuse | Arize AX | | -------------- | ---------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------- | | **Model** | **Usage-Based**: [Billable unit](/docs/administration/billable-units) = trace, observation, or score. | **Hybrid**: spans + ingestion volume (GB). | | **Free Tier** | 50k units/mo, 30-day retention, 2 users. | 25k spans/mo, 1 GB, 15-day retention. | | **Paid entry** | Core $29/mo (100k units, 90-day retention). | Pro $50/mo (50k spans, 10 GB, 30-day retention). | | **Retention** | 3 years on Pro and Enterprise. | 15 days Free, 30 days Pro, custom on Enterprise. | | **Self-host** | Core platform on free OSS; enterprise governance needs an [Enterprise license](/pricing-self-host). | Phoenix: free to self-host. AX: Enterprise. | | **Plans** | [Hobby (free), Core ($29/mo), Pro ($199/mo), optional Teams add-on ($300/mo), Enterprise ($2,499/mo)](/pricing). | [Free, Pro ($50/mo), Enterprise](https://arize.com/pricing/). Phoenix is separate and self-hosted. | ## Open Platform & Extensibility Langfuse is designed as a core infrastructure component, allowing teams to build custom internal tools on top of its API. | Feature | Langfuse | Arize AX | | ------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------- | | **API Access** | [API first](/docs/api-and-data-platform/features/public-api) for all data (traces, evals, prompts) and platform features. | API available, exposes only core resources. | | **Customizability** | Build custom workflows, evaluations, and [dashboards](/docs/metrics/features/custom-dashboards) using the SDK/API. | Custom evaluations and pipelines via SDK. | | **Data Access** | Query via API on all plans. [Scheduled blob exports](/docs/api-and-data-platform/features/export-to-blob-storage): Teams add-on, Enterprise, or self-hosted. | Export via UI, SDK, API, CLI. | ## Enterprise Security Both platforms serve large enterprises. Arize AX lists PCI DSS 4.0 among its certifications. Langfuse lists SOC 2 Type II and ISO 27001, with a [HIPAA-ready region](/security/hipaa) on Pro or higher, and supports [masking](/docs/observability/features/masking) to redact sensitive fields before ingest. | Feature | Langfuse | Arize AX | | ------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | | **Certifications** | **[SOC 2 Type II, ISO 27001](/security)**, GDPR, [HIPAA-ready region](/security/hipaa) (Pro+). | [SOC 2 Type II, HIPAA, PCI DSS 4.0, CSA Star Level 1](https://arize.com/docs/ax/security-and-settings/compliance). | | **Regions** | Cloud EU, US, Japan; HIPAA on Pro+. | Cloud US, EU, or CA ([pricing](https://arize.com/pricing/)). | | **Adoption** | Trusted by **21 of Fortune 50** & 129 of Fortune 500. | Strong enterprise adoption, including teams that already run Arize for classical ML. | | **Governance** | Org [RBAC](/docs/administration/rbac), [Enterprise SSO](/docs/administration/authentication-and-sso) and project RBAC: Teams add-on or Enterprise. [Audit logs](/docs/administration/audit-logs): Enterprise. Self-host OSS includes org RBAC and SSO; project RBAC and audit logs need Enterprise. | Organization/space RBAC with plan-specific scope; SSO, fine-grained space-level RBAC, audit logs on Enterprise ([pricing](https://arize.com/pricing/)). | ## Feature Highlights **Langfuse:** - **[Core Observability](/docs/observability/overview):** Best-in-class tracing with accurate [token and cost tracking](/docs/observability/features/token-and-cost-tracking) for 100+ models. - **[Prompt Management](/docs/prompt-management/overview):** Collaborative [playground](/docs/prompt-management/features/playground) with versioning, caching, fallbacks, and protected labels. - **Collaboration:** [Annotation queues](/docs/evaluation/evaluation-methods/annotation-queues), [comments](/docs/observability/features/comments) with @mentions, and [audit logs](/docs/administration/audit-logs). - **[Evaluations](/docs/evaluation/overview):** Flexible "[LLM-as-a-Judge](/docs/evaluation/evaluation-methods/llm-as-a-judge)" evaluators that can be run in-UI or via SDK pipelines. **Arize AX:** - **[Agentic Visualization](https://arize.com/docs/ax/instrument/agent-trajectory):** Specialized views for multi-agent conversation flows. - **[Data Fabric](https://arize.com/docs/ax/security-and-settings/data-fabric):** Sync with enterprise data lakes (Enterprise feature, currently waitlisted). - **Evaluation:** Session-level evaluation and retrieval diagnosis (RAG). AX also includes Signal and Alyx, with availability depending on plan. Already instrumented with OpenInference? Keep it and follow the [Arize AX migration](/resources/engineering/migrate-from-arize-ax) or the [Phoenix migration](/resources/engineering/migrate-from-phoenix). For a migration plan on Cloud or self-hosted, [talk to us](/talk-to-us). - [Get started free](https://cloud.langfuse.com) - [Talk to us](/talk-to-us) This comparison is out of date? Please [raise a pull request](https://github.com/langfuse/langfuse-docs/tree/main/content/resources/engineering) with up-to-date information. --- ## Agent Instructions This page is part of the [Langfuse](https://langfuse.com) documentation, published as plain Markdown for AI agents. Every page is available as Markdown by appending `.md` to its URL, or by sending an `Accept: text/markdown` header. This page: `https://langfuse.com/resources/engineering/best-phoenix-arize-alternatives.md`. ### Querying these docs If the answer is not on this page, query the documentation instead of guessing: - **Semantic search** across all Langfuse docs, returning an answer with the relevant pages and excerpts. Ask a specific, self-contained question: ```bash curl -sG "https://langfuse.com/api/search-docs" --data-urlencode "query=How do I trace a LangGraph agent?" ``` - **Index of every page**: , with per-section indexes [llms-docs.txt](https://langfuse.com/llms-docs.txt), [llms-integrations.txt](https://langfuse.com/llms-integrations.txt), and [llms-self-hosting.txt](https://langfuse.com/llms-self-hosting.txt). ### Before writing Langfuse code - **Install the [Langfuse Agent Skill](https://langfuse.com/docs/api-and-data-platform/features/agent-skill).** It encodes Langfuse's own best practices for instrumentation, prompt management, and evaluation, and materially improves results. - **Read [What does a good trace look like?](https://langfuse.com/docs/observability/best-practices.md)** before instrumenting an application. - **Verify endpoints, parameters, and response fields** against the [API reference](https://api.reference.langfuse.com) instead of inferring them from code examples. - **Use the [Langfuse CLI](https://langfuse.com/docs/api-and-data-platform/features/cli)** (`npx langfuse-cli api `) to read or write traces, prompts, datasets, and scores from the terminal. Found an error in these docs? Please open an issue at .