Phoenix vs TruLens

A side-by-side look at pricing, capabilities, pros, cons, and our editorial scores.

Tagline

Phoenix

Open-source LLM and agent observability platform with tracing, evals, and experimentation built on OpenTelemetry.

TruLens

Open-source evaluation and tracing framework for LLM apps and agents, built on OpenTelemetry.

Pricing

Phoenix

Freemium· AX Free: Free · AX Pro: $50 · AX Enterprise: Custom

TruLens

Free· Free, open source (Apache-licensed Python package)

Lowest paid tier

Phoenix

$50 · AX Pro

captured 2026-08-08

TruLens

—

Free trial

Phoenix

Yes

TruLens

Yes

API

Phoenix

Yes

TruLens

Yes

Platforms

Phoenix

api

TruLens

apicliweb

Open source

Phoenix

Yes

TruLens

Yes · MIT

GitHub stars

Phoenix

—

TruLens

3,579

checked 2026-09-29

Last GitHub push

Phoenix

—

TruLens

2026-09-29

First commit

Phoenix

—

TruLens

2020-11

Company

Phoenix

—

TruLens

TruEra

Model used

Phoenix

Multi-model

TruLens

Multi-model (LLM-as-judge)

Best for

Phoenix

Pick Phoenix if you're building LLM agents and want OpenTelemetry-native tracing and evals you can self-host without losing core features.

TruLens

Pick TruLens if you want a code-first, open-source way to trace and score LLM apps or agents without sending eval data to a hosted vendor.

Not for

Phoenix

Skip it if you want a fully managed, zero-ops observability SaaS with white-glove enterprise support out of the box.

TruLens

Skip it if you need a turnkey managed eval SaaS with a hosted UI, non-Python SDKs, or zero infra work.

Editorial score

Phoenix

7.0 / 10

TruLens

8.1 / 10

Use cases

Phoenix

llm-tracingagent-debuggingllm-evaluationprompt-experimentsrag-observability

TruLens

llm-evaluationrag-evaluationagent-tracingregression-testingobservability

Pros

Phoenix

Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell
Native OpenTelemetry means no vendor lock-in for instrumentation
Covers tracing, evals, annotation, and experiments in one tool
Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work

TruLens

Free and open source, no vendor lock-in on eval data
OpenTelemetry-native tracing plugs into existing observability stacks
Broad library of benchmarked feedback functions plus custom metrics
Framework-agnostic: works with LangChain, LlamaIndex, or raw SDK calls
Backed by Snowflake with active maintenance

Cons

Phoenix

Self-hosting still requires you to manage storage, retention, and upgrades
Eval UX is less polished than some managed competitors like LangSmith
Free cloud tier is capped at two instances

TruLens

Self-hosted library, no managed dashboard or hosted storage
LLM-as-judge metrics rack up model API costs you pay separately
Python-only SDK, no first-party JS/TS client

Website

Phoenix

phoenix.arize.com

TruLens

www.trulens.org

Editorial score: rule-based, 0–10, from AI-assisted profile inputs (see /methodology) — not a user rating; “—” means unscored. “Not listed” means we have no record of it, not that it is absent. GitHub figures and prices carry the date they were checked or captured; prices are shown as published, unconverted.

Pick Phoenix if

✅ Genuinely open source (ELv2) with self-host parity, not a crippled OSS shell
✅ Native OpenTelemetry means no vendor lock-in for instrumentation
✅ Covers tracing, evals, annotation, and experiments in one tool
✅ Framework-agnostic: LangChain, LlamaIndex, DSPy, CrewAI, raw SDK calls all work

Pick TruLens if

✅ Free and open source, no vendor lock-in on eval data
✅ OpenTelemetry-native tracing plugs into existing observability stacks
✅ Broad library of benchmarked feedback functions plus custom metrics
✅ Framework-agnostic: works with LangChain, LlamaIndex, or raw SDK calls

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