Langfuse alternative for traces, logs, and metrics

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Langfuse is an open-source platform for LLM tracing, prompt management, and evaluation. telemetry.dev collects traces, logs, and metrics from AI applications over OpenTelemetry and works out token usage and cost from them. The two overlap on tracing. Langfuse also covers prompts and evaluation, and you can host it yourself. telemetry.dev does neither.

We checked the Langfuse facts on this page against its pricing page and documentation on October 15, 2026. Plans change, so confirm them in the sources at the end before you decide.

At a glance

telemetry.devLangfuse Cloud
What it coversTraces, logs, metrics, token usage, and costTracing, prompt management, evaluation, and datasets
How you payOne monthly price per organizationA monthly plan price, plus usage above the included units
Free plan$0 for 30,000 units a month, 2 seats, and 1 projectHobby: $0 for 50,000 units a month and 2 users
First paid planPro: $25 a month for 500,000 units and 5 seatsCore: $29 a month for 100,000 units and unlimited users
Next planTeam: $50 a month for 2,000,000 units and unlimited seatsPro: $199 a month for 100,000 units and unlimited users
Usage above the planPro and Team keep ingesting, with no automatic overage fee$8 per 100,000 units, then $7 above 1,000,000 units, and less at higher volume
What counts as usageEach span, log record, or metric data pointEach trace, observation, or score
History you can view14, 30, or 90 days of retention, depending on the plan30 days on Hobby, 90 days on Core, and 3 years on Pro. Older data is kept and returns on upgrade
OpenTelemetryOTLP/HTTP traces, logs, and metrics, as protobuf or JSONOTLP/HTTP traces at /api/public/otel, as protobuf or JSON
EvaluationNonePrompt management, online and offline evaluation, datasets, and annotation queues
HostingUnited StatesUS, EU, or Japan cloud, or self-hosted from the open-source code

What a team would pay

The two products count usage differently. telemetry.dev counts every span, log record, and metric data point. Langfuse counts every trace, observation, and score. If each span becomes one Langfuse observation, a trace with 10 spans is 10 units in telemetry.dev and 11 in Langfuse: the trace plus its 10 observations.

Spans a monthtelemetry.devLangfuse Core
400,000$25 on Pro, with 30-day retention$56.20, with 90 days of history
1,800,000$50 on Team, with 90-day retention$169.60, with 90 days of history

At 400,000 spans in 40,000 traces, Langfuse counts 440,000 units. Core includes 100,000, and the other 340,000 cost $27.20 at $8 per 100,000, on top of the $29 plan. At 1,800,000 spans, Langfuse counts 1,980,000 units: 900,000 above the included amount cost $72 at $8 per 100,000, and the last 980,000 cost $68.60 at $7 per 100,000.

Your result depends on how many spans each trace has. Scores add Langfuse units, and logs and metrics add telemetry.dev units.

When telemetry.dev fits

  • You want a fixed monthly price with no automatic overage charges.
  • You want OpenTelemetry logs and metrics next to your traces, not traces alone.

When Langfuse fits

  • You need to host the platform yourself from open-source code.
  • You version prompts, or you test prompts and agents with evaluations and datasets.
  • You collect human feedback in annotation queues.
  • You need your data stored in the EU or in Japan.
  • You need to see data older than 90 days.

Send your spans to telemetry.dev

telemetry.dev receives standard OpenTelemetry traces, logs, and metrics over OTLP/HTTP. If your application already exports OpenTelemetry spans, change the exporter endpoint and the authorization header. The OpenTelemetry guide shows the setup, and the integrations index has a guide for each SDK, provider, and framework.

To compare the two products on the same data, send your spans to both at once. An OpenTelemetry Collector can export one stream of spans to Langfuse and to telemetry.dev.

Sources