Opik vs Pydantic Logfire
Both are observability & tracing tools. Here is how they actually differ on price, billing model and deployment.
Opik
Comet's open-source LLM observability and eval platform - the cheapest paid cloud in the category at $19/mo, and the most permissive OSS license. Apache-2.0, full feature set self-hosted, and the fastest-growing project of its peers.
Pydantic Logfire
OpenTelemetry-native observability from the Pydantic team, and the cheapest credible option in the category at $2 per million records with 10M free every month. The catch is that metrics count as records, and common integrations emit them silently.
| Opik | Pydantic Logfire | |
|---|---|---|
| Category | Observability & Tracing | Observability & Tracing |
| Our rating | 5/5 | 5/5 |
| Starting price | $19/mo | $49/mo |
| Billing meter | span | record |
| Free plan | Yes | Yes |
| Free self-hosting | Yes, free | No or paid tier only |
| Best for | Teams that want a genuinely feature-complete open-source observability platform, or the cheapest managed cloud, without a license or feature-gate catch | Teams that want one observability tool for their whole application rather than an LLM-specific silo, are comfortable on OpenTelemetry, and care about predictable, genuinely low cost. Especially strong for Python shops already using Pydantic or Pydantic AI. |
Our verdict on Opik
The most honest open-source deal in the category - Apache-2.0, the full feature set self-hosted with no gates, and if you want managed, the cheapest cloud tier here at $19/mo. It is also the fastest-growing project of its peers, which tells you the market agrees. The one real watch-out is per-seat pricing - it scales poorly as your team grows, and a few large-project users report UI slowdown.
Full Opik review →Our verdict on Pydantic Logfire
Logfire is the best value in this category and it is not close. Ten million free records a month, then $2 per million, with no metering on seats, hosts or projects. The free tier hard-caps rather than billing you, which means a runaway instrumentation loop pauses ingestion instead of generating a five-figure invoice - a design decision almost nobody else in observability makes. It is full-stack OpenTelemetry rather than an LLM silo, so the database query that made your agent slow appears in the same trace as the LLM call, and you can query all of it with PostgreSQL-compatible SQL. The one real trap is the billing unit. Logfire bills records, and records include metrics, and integrations like httpx, SQLAlchemy and FastAPI emit aggregate metrics under the hood whether you asked for them or not. Teams get surprised by this. Turn off auto-emitted metrics you do not need and the economics are excellent.
Full Pydantic Logfire review →Frequently Asked Questions
What is the main difference between Opik and Pydantic Logfire?
Opik: Teams that want a genuinely feature-complete open-source observability platform, or the cheapest managed cloud, without a license or feature-gate catch Pydantic Logfire: Teams that want one observability tool for their whole application rather than an LLM-specific silo, are comfortable on OpenTelemetry, and care about predictable, genuinely low cost. Especially strong for Python shops already using Pydantic or Pydantic AI. Both sit in Observability & Tracing, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Opik or Pydantic Logfire?
It depends entirely on your workload shape, because they meter differently - Opik bills on span and Pydantic Logfire bills on record. Published starting prices are $19/mo and $49/mo respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Opik or Pydantic Logfire?
Opik: Yes, free. Pydantic Logfire: No or paid tier only. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.