LLM Observability & Evals

The 3 Best OpenTelemetry Alternatives in 2026

Looking for an alternative to OpenTelemetry? Below we compare the best llm observability & evals alternatives by pricing, free tiers, and what each is best for — so you can pick the right fit for your budget and stack.

Category

LLM Observability & Evals

OpenTelemetry pricing

Free tier available

Free tier

Yes

Alternatives

3 compared

Why look for a OpenTelemetry alternative?

OpenTelemetry is a solid llm observability & evals choice, but it isn't the right fit for everyone. The most common reasons teams evaluate alternatives:

  • −No UI, evals or prompt management of its own
  • −You still have to pick and pay for (or run) a backend
  • −GenAI conventions are still evolving, so attribute names can shift

OpenTelemetry vs Alternatives — Quick Comparison

ToolPricingFree tierRating
OpenTelemetryYou searchedFree4.6
1.LangfuseFree · paid from $29/mo4.7
2.BraintrustFree · paid from $249/mo4.6
3.LangSmithFree · paid from $39/seat/mo4.5

Top OpenTelemetry Alternatives, Explained

Langfuse

1. Langfuse

Free tier4.7· Free · paid from $29/mo

Langfuse is the most widely deployed open-source platform in this category: traces, cost and latency per call, datasets, LLM-as-judge evals and a versioned prompt registry. ClickHouse acquired it in January 2026, and the MIT licence and self-hosting path were kept. The cloud prices by units (traces, observations and scores) rather than seats. Core is $29/month for 100k units and 90 days of data, and each extra 100k units is $8. Pro at $199 buys three years of retention rather than more volume.

  • Genuinely open source and self-hostable
  • Unit pricing does not punish adding teammates
  • Framework-agnostic: OpenTelemetry, LangChain, LlamaIndex, raw SDKs
Braintrust

2. Braintrust

Free tier4.6· Free · paid from $249/mo

Braintrust starts from evaluation rather than tracing: experiments, datasets, scorers and a playground for comparing prompts and models side by side, with production logging on the same data. Every plan has unlimited users. The free Starter plan includes 1 GB of processed data and 10k scores with 14-day retention. Pro is $249/month for 5 GB and 50k scores, then $3/GB and $1.50 per 1,000 scores, and qualifying startups can get 6–12 months of Pro free. It is closed source; there is no self-hosted tier below Enterprise.

  • Strongest eval and experiment workflow in the category
  • Unlimited users, so PMs and domain experts can review outputs
  • Generous startup program
LangSmith

3. LangSmith

Free tier4.5· Free · paid from $39/seat/mo

LangSmith comes from the team behind LangChain and LangGraph, and it shows: agent graphs, tool calls and state transitions render without extra instrumentation, and it now ingests OpenTelemetry for everything else. The free Developer plan is one seat with 5,000 base traces a month. Plus is $39 per seat with 10,000 traces and pay-as-you-go above that. Base traces keep 14 days; 180-day extended retention costs more per trace. LangChain has repriced traces more than once in 2026, so model your volume in its calculator. Self-hosting is an Enterprise option.

  • Best-in-class visibility into LangGraph and LangChain agents
  • Mature evals, datasets and annotation queues
  • Accepts OpenTelemetry traces from non-LangChain code

Frequently Asked Questions

What are the best alternatives to OpenTelemetry in 2026?⌄

The best OpenTelemetry alternatives in 2026 are Langfuse, Braintrust, LangSmith. Each is a llm observability & evals option you can compare on pricing, free tiers, and features in the table above.

Is there a free alternative to OpenTelemetry?⌄

Yes — Langfuse, Braintrust, LangSmith offer free tiers, making them strong free OpenTelemetry alternatives for bootstrapped startups.

Why look for a OpenTelemetry alternative?⌄

A common reason teams switch is no ui, evals or prompt management of its own. Beyond that, people compare llm observability & evals tools on pricing, specific feature gaps, ease of use, and whether an open-source or free-tier option exists — so they can pick the best fit for their stack and budget.

What is the cheapest OpenTelemetry alternative?⌄

Langfuse is among the most affordable OpenTelemetry alternatives — free · paid from $29/mo. Check the comparison table above for the full pricing breakdown.

Which OpenTelemetry alternative is rated highest?⌄

Langfuse is the highest-rated OpenTelemetry alternative in our catalog at 4.7 out of 5, making it a strong pick if you want a well-reviewed option.

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