Langfuse is observability for the LLM features you ship: traces, prompts, evaluations. Fastpace is governance for the AI tools your engineers use while shipping them. The two are often bought by the same company for different reasons.
Langfuse pricing and capabilities were read from the vendor’s own pages in October 2026. Products change. If something here is out of date, tell us and we will correct it.
We write this section first. A comparison that only lists wins is an advert, and it reads like one.
The project is open source and self-hosting costs nothing but infrastructure. That is a real advantage and we do not match it.
50,000 units a month on the Hobby plan, with no credit card.
Prompt management and evaluation next to the traces, which is exactly what an LLM product team needs.
Including Enterprise at $2,499 a month, which almost nobody discloses.
Langfuse watches your application. Fastpace watches the agents writing your application, on the developer machine.
Policy compiled into each agent tool, which blocks. Tracing describes what already happened.
Each entry hashes the previous one and is signed by the install, so tampering is visible. Traces are not built for that question.
Commit trailers connect a change to the run behind it, including the policy decisions that applied.
The same ten questions appear on every Fastpace comparison, so the pages can be read against each other. A tilde means partly, and it carries a note.
| Capability | Langfuse | Fastpace |
|---|---|---|
| Governs more than one AI coding tool | ✕ | ✓ |
| Enforces policy where the developer works | ✕ | ✓ |
| Writes a signed receipt for each AI call† | ∼ | ✓ |
| Records the model, endpoint and training opt-out per call | ∼ | ✓ |
| Keeps a tamper-evident chain an auditor can verify | ✕ | ✓ |
| Ties a commit back to the run that produced it | ✕ | ✓ |
| Produces an AI bill of materials | ✕ | ✓ |
| Maps evidence to compliance frameworks | ✕ | ✓ |
| Finds AI use outside the governed tools | ✕ | ✓ |
| Runs locally, with no prompt text leaving the machine† | ✓ | ✓ |
Langfuse for the product you are building, Fastpace for how it gets built. If an incident ever starts with "which model wrote this code", that is the Fastpace chain, not the trace.
They are not alternatives and nobody should treat them as such. The overlap is the word observability, which means two different things on either side of the merge.
Hobby is free with 50,000 units a month. Core is $29 a month, Pro $199, Enterprise $2,499, each including 100,000 units. A Teams add-on is $300 a month. Self-hosting the open source version is free.
Free tier: Hobby plan, free, plus free self-hosting. · Checked October 2026.
Fastpace: Community is free. Team is $29 per editor seat per month billed annually, or $36 monthly, with the first five seats free for twelve months. Platform is $99 per editor seat per month billed annually. Enterprise is custom. Viewer seats for CISO and GRC are free on Team.
No tool does. Fastpace produces evidence and maps it to the controls a framework names. The judgment stays with your auditor, and Fastpace holds no certification on your behalf.
The policy compiler reports what each target can and cannot enforce. Some settings are protected by the operating system and some a determined developer can route around. We would rather print that than imply a guarantee.
We publish no customer logos we cannot name and no statistics we cannot source. Ask us for a pilot rather than a reference wall.
The CLI ships under the Elastic 2.0 licence. It runs locally in your repository, and we call that source-available because that is what it is.
Hobby is free with 50,000 units a month. Core is $29 a month, Pro $199 and Enterprise $2,499, each including 100,000 units, with a Teams add-on at $300. Self-hosting the open source version is free. Checked October 2026.
It traces calls your instrumented code makes. Coding agents on a developer machine are not instrumented by your application, so in practice no.
The CLI ships under the Elastic 2.0 licence and runs locally in your repository. It is source-available rather than open source, and we say so plainly.
Only in that both record what a model was asked and what it said. The question each is built to answer is different.