Tool profile
Langfuse: cost, fit and limits
Langfuse is an open-source LLM engineering platform, now part of ClickHouse, that stores and versions prompts, records traces of model calls and runs evaluations. Developers fetch prompts from the registry through SDKs, while non-technical colleagues can edit them in the web interface. It is offered as a hosted cloud service or as self-hosted software.
What to know first
Langfuse sells usage in units, not seats, so the bill follows how much your application logs. Hobby is free with 50k units a month, and every paid tier above it has unlimited users. Prompt management is one module next to tracing and evaluation, which means a prompt version can be tied to the traces it produced. The same code runs in the cloud and on your own servers.
Langfuse at a glance
| Maker | Langfuse GmbH (part of ClickHouse), Germany |
|---|---|
| Free plan | Yes |
| Entry price | $29 per month (Core) |
| API access | Yes |
| Category | Best AI Prompt Management Software in 2026, rank 1 of 10 |
| Website | langfuse.com |
Who Langfuse is best for
Product engineers shipping prompt changes weekly
Prompts live outside the codebase, so a wording change goes through the UI and reaches the application on the next fetch, with no code deploy attached to it.
Teams with a data-residency rule
The cloud runs in three regions (US, EU in Ireland, Japan), and self-hosting works in any region or fully offline, which covers policies that forbid sending prompts abroad.
Startups and open-source projects
The pricing page lists 50% off the first year for startups and $300 a month in credits for open-source projects, which offsets the $199 Pro step.
Researchers and students
The page says research and student users can get up to 100% off, which makes the Core and Pro limits usable for thesis or lab work.
Langfuse plans and pricing
| Plan | Price | What it includes |
|---|---|---|
| Hobby | Free, no credit card | 50k units a month, 30 days of data access, 2 seats, and a choice of US, EU or Japan region. No SOC 2, ISO 27001 or HIPAA. |
| Core | $29 per month | 100k units a month, 90 days of data access and unlimited seats. Extra usage is billed per 100k units, starting at $8. |
| Pro | $199 per month | 100k units, 3 years of data access, opt-in retention management, SOC 2 and ISO 27001 reports and a HIPAA BAA on request. Teams add-on costs $300 more. |
| Enterprise | $2,499 per month | Everything in Pro with SOC 2, ISO 27001 and HIPAA listed, plus a dedicated HIPAA region alongside the US, EU and Japan regions. |
Checked October 2026.
What Langfuse does
- Central prompt registry
- Prompts are stored and versioned outside application code. Labels such as a production label mark which version each environment should fetch, so promotion is a label move.
- Client-side caching
- The SDKs cache prompts in the application, so retrieval adds no network call at request time and a brief Langfuse outage does not stop a cached prompt from being served.
- Prompt-to-trace links
- A prompt can be linked to the traces it generated, and the docs describe analyzing performance by prompt version. This is how you see which wording raised cost or errors.
- Editing without a deploy
- Non-technical team members edit prompts in the UI, and the application picks up the latest labeled version without a release. Edits are saved as new versions, and the label decides when they go live.
- Tiered volume pricing
- Overage falls from $8 per 100k units up to 1M, to $7, $6.50 and $6 at higher volumes, so heavy loggers can model cost from the table.
How Langfuse handles your data
Langfuse Cloud runs on AWS and ClickHouse Cloud in us-west-2 (Oregon, also the HIPAA region), eu-west-1 (Ireland) and ap-northeast-1 (Japan). The security page lists SOC 2 Type II, ISO 27001 and HIPAA, annual penetration tests, a DPA and GDPR compliance, with reports on request. Customers control retention, deletion and masking. The privacy policy names ClickHouse, Inc. as the entity and says nothing about training models on customer data, and the security page gave no retention periods or subprocessor list.
Where Langfuse falls short in practice
- Pro is the compliance gate. Hobby and Core state no SOC 2, ISO 27001 or HIPAA, so a buyer who needs a report pays $199 a month, or $2,499 for Enterprise, not the $29 entry price.
- Short data windows on low tiers. Hobby gives 30 days and Core 90 days of data access, so a prompt-performance comparison across a quarter needs Pro. Only Pro and Enterprise offer opt-in retention management.
- Units grow with chatty agents. Each logged event counts, so an agent that makes many steps per request consumes the 100k included units fast. Past that, every extra 100k costs $8 on the entry rates.
- Ownership by ClickHouse. The privacy policy now names ClickHouse, Inc. as the company. Buyers with a vendor-concentration rule should check the roadmap commitment in writing before committing to multi-year terms.
Works with
Alternatives to Langfuse
Langfuse: common questions
Can I self-host Langfuse for free?
Yes. The pricing page says Langfuse is open source and can be self-hosted at no cost through Docker Compose or Kubernetes templates. Self-hosted pricing details sit on a separate page that was not opened here, and security page notes self-hosting can run fully offline or air-gapped in any region or provider.
How do Langfuse labels decide which prompt the app uses?
Labels are names attached to prompt versions, and the application asks for a prompt by name and label. Moving the production label to a newer version changes what the next fetch returns, with no code release. The docs say the SDKs cache prompts, so retrieval is not network-bound.
What counts as a unit in Langfuse pricing?
Pricing is by units, with 50k on Hobby and 100k on Core, Pro and Enterprise each month. The page does not define a unit in the content read, so check the docs for how traces and events convert before estimating a bill. Extra units start at $8 per 100k.
Does Langfuse have EU hosting?
Yes. Langfuse Cloud offers an EU region in eu-west-1 (Ireland) alongside US and Japan, and every paid and free tier lists that choice. The security page also describes a DPA and GDPR compliance, though the privacy policy names a California-based entity.
Is there a discount for startups or open-source projects?
The pricing page lists 50% off the first year for startups, up to 100% for research and students, $199 a month in credits for nonprofits and $300 a month in credits for open-source projects in their first year. Eligibility rules were not detailed on the page.