Prevents falling behindBuilding blockAI-native

Langfuse

Langfuse GmbH, Berlin (owned by ClickHouse, Inc. since 2026-01-16) ·langfuse.com· As of: 2026-07-30

Once you build language models into a product, you cannot see what the model was asked, what it answered, what the call cost, or whether a prompt change improved or degraded quality. Langfuse records every model call, versions the prompts and scores answers against fixed test cases.

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ClaudeChatGPTPerplexity

Our verdict

If you do not record model calls, you cannot trace faults, cannot evidence quality and cannot attribute cost. That is ground you avoid losing, not an advantage you build. The platform itself has become interchangeable, several vendors ship the same feature set. What gains value over time is your own body of test cases and evaluation runs, and that belongs to the operator, not to the tool. It can be exported and carried elsewhere. Hence the verdict: it keeps you from falling behind, no more.

Evidence:As of 2026-07-30Plans, included units, retention periods, overage tiers, add-on and audit logging only in the top planOpen sourceAs of 2026-07-30Certifications, encryption, penetration testing, available regionsOpen sourceAs of 2026-07-30EU region in Ireland on AWS eu-west-1, full separation between regions, switching only via a new account and a migration of your ownOpen sourceAs of 2026-07-30No training on client data, retention configurable per project, data processing agreement availableOpen sourceAs of 2026-07-30Data processing addendum with EU standard contractual clauses incorporated, version dated 10 April 2026Open sourceAs of 2026-07-30Full list of subprocessors and group affiliates, dated 10 April 2026Open sourceAs of 2026-07-30For pay-as-you-go billing the contracting party is Langfuse GmbH; governing law is DelawareOpen sourceAs of 2026-07-30Acquisition by ClickHouse on 16 January 2026, commitment to continue under the MIT licence and to keep self-hosting availableOpen sourceAs of 2026-07-30Legal entity Langfuse GmbH, Charlottenburg local court HRB 248821B, managing directors Aaron Katz and Clemens RawertOpen sourceAs of 2026-07-30MIT core without limits; audit logs, masking, retention policies, project-level roles and SCIM require a licence keyOpen sourceAs of 2026-07-30Scheduled export of traces, observations and scores in Parquet, CSV, JSON or JSONLOpen sourceAs of 2026-07-30Vendor adoption figures: GitHub stars, Docker pulls, monthly SDK installs, use across Fortune 50 and Fortune 500 companiesOpen source

Who it fits

Solo

suitable

The free tier covers 50,000 units a month and two seats, with retention ending after 30 days. That is enough for a single application in trial, and the MIT-licensed core can also be self-hosted at no charge.

Mid-market

suitable

Twenty-nine dollars a month with unlimited seats and 90 days of retention suits a team running one or two AI features in production. The unknown is consumption, because every recorded event counts and multi-step chains produce many events per request.

Enterprise

suitable with caveats

Conditional, because the very parts a large organisation must have sit at the expensive end. Single sign-on and fine-grained roles cost an extra 300 dollars a month, audit logs and SCIM provisioning only arrive in the 2,499 dollar plan. When self-hosting, those same features sit behind a paid licence key whose price is not published.

Buy, switch or build

Off-the-shelf

Log model calls into the observability stack you already run

If you already run an observability platform, model calls can be filed there as ordinary traces. That saves a separate procurement, access rights are settled and the storage location is known. What is missing is any semantics for input, output, prompt version and score. You can see that a call was slow or expensive, but not whether the answer was usable. With AI features that is precisely the question that matters.

AI-native

One of the competing AI-native platforms

The category as a whole is AI-native and Langfuse is part of it. The difference between vendors barely lies in features any more, but in the licence, the storage location and who owns the vendor. Langfuse distinguishes itself through the MIT-licensed core and the selectable EU region. Choosing a closed platform instead gives up exactly that escape route and leaves you dependent on the vendor's export interface.

Build it yourself

Trace collection into your own database

The ingestion path is manageable: standard OpenTelemetry traces into your own database plus a plain view on top. That is enough as long as only developers look at it. It breaks on the parts that carry the real effort, namely evaluation runs against fixed test cases, prompt versions with approval, and an interface where domain experts without coding skills can judge answers. Building that layer yourself costs more, permanently, than it returns.

Our advice

  • Solo: Free tier or self-hosting, both work.
  • Mid-market: Buy, pick the EU region, recheck consumption after four weeks.
  • Enterprise: Buy or self-host, but settle first what audit logging costs and who the contracting party is.

Who is behind it

Staying power: Funded

The legal entity is German, control has not been since January 2026. Operations today rest on a heavily funded acquirer rather than on a vendor that has been self-sustaining for years. The MIT-licensed core lowers the risk noticeably, because continued operation stays possible without the vendor.

  • Change of ownership: acquired by ClickHouse, Inc., announced on 16.01.2026; purchase price not disclosedAs of 2026-07-30Acquisition by ClickHouse on 16 January 2026, commitment to continue under the MIT licence and to keep self-hosting availableOpen source · As of 2026-07-30
  • Funding of the owner: USD 400 million Series D led by Dragoneer, announced the same dayAs of 2026-07-30clickhouse.com/…Open source · As of 2026-07-30
  • Legal entity and register: Langfuse GmbH, Oranienburgerstraße 91, 10178 Berlin, commercial register Amtsgericht Charlottenburg HRB 248821B, managing directors Aaron Katz and Clemens RawertAs of 2026-07-30Legal entity Langfuse GmbH, Charlottenburg local court HRB 248821B, managing directors Aaron Katz and Clemens RawertOpen source · As of 2026-07-30
  • Adoption: more than 32,000 GitHub stars, more than 6 million Docker pulls, more than 50 million SDK installs per month, in use at 21 of the Fortune 50 and 129 of the Fortune 500As of 2026-07-30Vendor adoption figures: GitHub stars, Docker pulls, monthly SDK installs, use across Fortune 50 and Fortune 500 companiesOpen source · As of 2026-07-30
  • Certification: SOC 2 Type II and ISO 27001, audited annually, annual independent penetration testsAs of 2026-07-30Certifications, encryption, penetration testing, available regionsOpen source · As of 2026-07-30
  • Licence of the core: MIT, expressly confirmed by the acquirer to remain so after the takeover, self-hosting at production scale permittedAs of 2026-07-30Acquisition by ClickHouse on 16 January 2026, commitment to continue under the MIT licence and to keep self-hosting availableOpen source · As of 2026-07-30

Cost of leaving: Low

Three routes lead out and all of them are open. The core is MIT-licensed and can be self-hosted. Traces, observations and scores can be exported on a schedule to S3, Google Cloud Storage or Azure Blob Storage in Parquet, CSV, JSON or JSONL, at intervals from 20 minutes to weekly. On top of that come exports from the interface and a public API. One limit remains: audit logs, masking at ingestion, retention policies and project-level roles are not part of the MIT core. Anyone relying on those cannot simply fall back to the free self-hosted route.

Regulation and data

How to read the traffic lightHow to read the traffic lightThe traffic light rates how well a point is evidenced, not how good the tool is. It draws only on the value, note and source held in the profile. Where a statement is missing, it rates the absence, not a guess. A well-reasoned "unclear" on a point that matters little for this tool is yellow. A missing source on a point that decides whether you can use it at all is red.documented, no condition attacheddocumented, tied to a conditiondocumented, but unfavourableopen on a point that decides usability
Data processing agreementScale for this point: Data processing agreementdocumented, no condition attached: Auftragsverarbeitungsvertrag öffentlich abrufbar und ohne weitere Bedingung Bestandteil des Vertrags; oder er entfällt nachvollziehbar begründet, weil kein Anbieter Kundendaten verarbeitet.documented, tied to a condition: Vertrag existiert, ist aber an einen Tarif gebunden, nur nach Anfrage einsehbar oder allein in den Nutzungsbedingungen geregelt statt als eigenes Dokument.documented, but unfavourable: Kein Auftragsverarbeitungsvertrag im üblichen Sinn: entweder weil der Anbieter für das Kerngeschäft eigenständig Verantwortlicher ist und stattdessen eine andere Konstruktion gilt, oder weil öffentlich offen bleibt, ob überhaupt einer angeboten wird.open on a point that decides usability: Weder ein Vertrag noch ein dokumentierter Weg zu einem Vertrag; der Einkauf hätte nichts, worauf er sich stützen kann.documented, no condition attachedyes, the data processing agreement of its owner ClickHouse, version of 10.04.2026, becomes part of the contractAs of 2026-07-30Data processing addendum with EU standard contractual clauses incorporated, version dated 10 April 2026Open sourceThe former Langfuse address for this document now redirects to the ClickHouse version. The EU standard contractual clauses are incorporated by reference and count as executed with the agreement.As of 2026-07-30
Storage locationScale for this point: Storage locationdocumented, no condition attached: EU-Speicherort ohne Zusatzkosten und ohne Tarifbindung, oder der Ort ist vollständig selbst bestimmbar, weil das Werkzeug im eigenen Betrieb läuft.documented, tied to a condition: EU-Speicherort möglich, aber an einen Tarif, einen gesondert zu aktivierenden Zusatz oder einen Umzug in eine getrennte Umgebung gebunden; oder die EU-Region ist nicht die Voreinstellung.documented, but unfavourable: Kein EU-Speicherort, der Ort ist aber eindeutig benannt, sodass die Folgen bewertbar sind.open on a point that decides usability: Der Speicherort ist öffentlich nicht benannt oder vom Kunden nicht steuerbar, sodass sich die Verarbeitung nicht verorten lässt.documented, no condition attachedEU region Ireland on AWS eu-west-1 under cloud.langfuse.com, selectable at sign-upAs of 2026-07-30EU region in Ireland on AWS eu-west-1, full separation between regions, switching only via a new account and a migration of your ownOpen sourceFurther regions are the United States in Oregon, Japan in Tokyo and a separate region for health data. Data, accounts and infrastructure are fully separated between regions. Switching is not built in, it requires a new account and a migration of your own.As of 2026-07-30
SubprocessorsScale for this point: Subprocessorsdocumented, no condition attached: Vollständige öffentliche Liste der Unterauftragnehmer mit Zweck und Land; oder es gibt keine, weil das Werkzeug im eigenen Betrieb läuft.documented, tied to a condition: Liste existiert und ist benannt, aber nur nach Anfrage oder nach Zugang zu einem Vertrauensportal einsehbar, oder sie nennt Zweck und Land nicht vollständig.documented, but unfavourable: Keine geführte Liste; namentlich stehen nur einzelne Dienste in der Datenschutzerklärung, überwiegend solche der eigenen Website.open on a point that decides usability: Weder eine Liste noch eine Nennung der Verarbeiter des Produkts, und kein dokumentierter Weg, sie zu erfahren.documented, no condition attachedcomplete subprocessor list published, as of 10.04.2026As of 2026-07-30Full list of subprocessors and group affiliates, dated 10 April 2026Open sourceNamed are AWS as operator of the customer-selected region, plus Salesforce with Slack, Pylon Labs, Google Workspace, Waypoint Tech, GitHub and kapa.ai for support and operations, all in the United States, along with nine ClickHouse group companies across eight countries.As of 2026-07-30
Third-country transferScale for this point: Third-country transferdocumented, no condition attached: Keine Übermittlung in ein Drittland, oder die Übermittlung findet statt und die Grundlage ist benannt und im Vertrag verankert, etwa Standardvertragsklauseln, Angemessenheitsbeschluss oder EU-US-Datenschutzrahmen.documented, tied to a condition: Übermittlung findet statt, eine Grundlage ist genannt, aber ohne Zuordnung, welcher Empfänger auf welcher Grundlage arbeitet.documented, but unfavourable: Übermittlung findet statt und die eigenen Unterlagen widersprechen sich, oder die genannte Grundlage bezieht sich erkennbar nur auf einen Randbereich wie die Marketing-Website.open on a point that decides usability: Übermittlung findet erkennbar statt und eine Grundlage wird nirgends genannt.documented, no condition attachedyes, transfer to the United States does take place, covered by the EU standard contractual clausesAs of 2026-07-30For pay-as-you-go billing the contracting party is Langfuse GmbH; governing law is DelawareOpen sourceThe payload data stays in the chosen region. All support and administrative services, however, sit in the United States. Also relevant: for pay-as-you-go billing the terms name Langfuse GmbH as the contracting party, in every other case ClickHouse. The terms name the law of the US state of Delaware as governing law throughout, with no carve-out for EU customers.As of 2026-07-30
Training on customer dataScale for this point: Training on customer datadocumented, no condition attached: Vertraglich oder in der Datenschutzerklärung ausdrücklich ausgeschlossen, mit Erstreckung auf die eingesetzten Modellanbieter; oder es gibt keine Datenübertragung an einen Anbieter.documented, tied to a condition: Ausschluss ab einem bestimmten Tarif, oder die Zusage steht nur auf einer Dokumentationsseite statt im Vertrag, oder die Frage stellt sich für das Werkzeug sachlich kaum und der Anbieter schweigt dazu.documented, but unfavourable: Nutzung ist die Voreinstellung und nur ein Widerspruch beendet sie; oder der Anbieter trainiert eigene Modelle auf bereinigten Kundendaten.open on a point that decides usability: Keine Aussage, obwohl das Werkzeug KI-Funktionen auf Kundeninhalten betreibt.documented, no condition attachedno, expressly ruled outAs of 2026-07-30No training on client data, retention configurable per project, data processing agreement availableOpen sourceIn its privacy FAQ the vendor states that it does not train or fine-tune ML or LLM models on client data. Model-based evaluations run through the customer's own model connections, so no additional model vendor is introduced by the tool.As of 2026-07-30
Retention and deletionScale for this point: Retention and deletiondocumented, no condition attached: Löschfristen nach Vertragsende beziffert und die Löschung oder Rückgabe zugesagt; oder die Fristen bestimmt der Betreiber selbst, weil das Werkzeug im eigenen Betrieb läuft.documented, tied to a condition: Löschung ist zugesagt, die Fristen sind aber nur teilweise beziffert, oder Sicherungskopien sind ausdrücklich ausgenommen.documented, but unfavourable: Nur der Grundsatz der Erforderlichkeit ohne jede Frist nach Vertragsende, oder Fristen sind allein für Randbereiche wie Website-Protokolle genannt.open on a point that decides usability: Keine Aussage zu Aufbewahrung und Löschung.documented, no condition attachedconfigurable per project from a minimum of 3 days up to unlimited, deletion runs nightly; capped by plan: 30 days on the free plan, 90 days on the USD 29 plan, 3 years from USD 199 upwardsAs of 2026-07-30No training on client data, retention configurable per project, data processing agreement availableOpen sourceDeleting individual traces, whole projects or the entire organisation is possible through the interface and the API. The retention policy itself is one of the licensed features when self-hosting.As of 2026-07-30
CertificationsScale for this point: Certificationsdocumented, no condition attached: Mehrere anerkannte Nachweise, benannt mit Norm, Fassung und Geltungsbereich, und bezogen auf den Anbieter selbst.documented, tied to a condition: Ein anerkannter Nachweis für den Anbieter belegt, der Bericht aber nur auf Anfrage, oder der Nachweis hängt an einem Tarif, oder der Geltungsbereich bleibt teilweise offen.documented, but unfavourable: Nur pauschale Nennung ohne Norm-Fassung und Geltungsbereich, oder bloße Selbstauskunft, oder die Nachweise gehören dem Infrastrukturanbieter statt dem Anbieter, oder der Prüfzeitraum ist erkennbar veraltet, oder die eigenen Angaben widersprechen sich.open on a point that decides usability: Kein Nachweis genannt und keine Sicherheits- oder Vertrauensseite vorhanden.documented, no condition attachedSOC 2 Type II and ISO 27001 for Langfuse Cloud, audited annually, plus annual independent penetration tests and continuous vulnerability scanningAs of 2026-07-30Certifications, encryption, penetration testing, available regionsOpen sourceThe public pages do not state clearly at which plan level the report and certificate are actually handed over. That belongs in the conversation before signing.As of 2026-07-30
EU AI Act, Article 50Scale for this point: EU AI Act, Article 50documented, no condition attached: Der Anbieter macht eine belegte Aussage, die die eigene Pflicht trägt, etwa Modelldokumentation und Zertifizierung nach ISO/IEC 42001; oder das Werkzeug enthält nachvollziehbar begründet kein KI-System im Sinne der Verordnung.documented, tied to a condition: Der Anbieter äußert sich zur Verordnung oder ordnet die eigene Funktion ein, eine benannte Zusage zu den Transparenzpflichten aus Artikel 50 fehlt aber; oder das Werkzeug enthält kein KI-System, das gegenüber Menschen auftritt, und der Anbieter schweigt.documented, but unfavourable: Das Produkt enthält KI-Funktionen, der Anbieter schweigt dazu oder trägt ein Selbstetikett ohne Nachweis; die Kennzeichnung ist vom Betreiber aber selbst setzbar.open on a point that decides usability: KI spricht im Produkt unmittelbar mit Endkunden und der Anbieter sagt zu Artikel 50 nichts; die Kennzeichnung lässt sich ohne Zusage des Anbieters nicht sicher setzen.documented, tied to a conditionunclearNeither the security page nor the compliance FAQ says anything about the EU AI Act. The tool is not a model provider either, it records calls to other people's models. It can therefore help you meet your own documentation duties, but carries no visible commitment of its own. Ask and get it in writing.no source given · As of 2026-07-30
Audit loggingScale for this point: Audit loggingdocumented, no condition attached: Nachvollziehbares Protokoll über Zugriffe und Änderungen in allen Tarifen enthalten, mit benannter Frist und Ausleitung in eigene Systeme; oder die Nachvollziehbarkeit liegt vollständig in eigener Hand, weil das Werkzeug im eigenen Betrieb läuft.documented, tied to a condition: Protokoll vorhanden, aber an einen höheren Tarif oder einen kostenpflichtigen Zusatz gebunden, oder die Ausleitung fehlt in den unteren Stufen; Reichweite und Frist sind benannt.documented, but unfavourable: Protokolle sind nur anbieterseitig beschrieben, oder Reichweite und Frist bleiben offen, sodass sich Nachweispflichten nicht planen lassen.open on a point that decides usability: Öffentlich nicht belegt, ob der Kunde überhaupt ein auswertbares Protokoll erhält.documented, tied to a conditiontamper-evident audit logging only from the USD 2,499 per month plan upwards, when self-hosting only with a paid licence keyAs of 2026-07-30Plans, included units, retention periods, overage tiers, add-on and audit logging only in the top planOpen sourceThe pricing page lists audit logs and SCIM only in the top plan. When self-hosting, the same features sit behind the enterprise licence key, whose price is not published and which the vendor page ties to a ClickHouse commercial plan.As of 2026-07-30

What it really costs

Entry price

Free for 50,000 units a month, two seats and 30 days of retention. The first paid plan costs 29 dollars a month and includes 100,000 units, unlimited seats and 90 days of retention. Alternatively the MIT-licensed core can be self-hosted at no charge.As of 2026-07-30Plans, included units, retention periods, overage tiers, add-on and audit logging only in the top planOpen source

As of 2026-07-30

What gets expensive

In two places. First consumption: beyond the included quota, each additional 100,000 units costs 8 dollars, falling to 6 dollars at volume. A chain with many intermediate steps per request produces a multiple of the expected units, and nobody models that in advance. Second the governance features: single sign-on and roles add 300 dollars a month, while audit logs and SCIM jump the bill from 199 to 2,499 dollars a month. If you only need those because an audit demands them, you pay that jump mid-year.

What it displaces

  • Model calls with no record at all
  • Prompt versions hard-coded in the codebase
  • Evaluation runs kept in a spreadsheet

Interfaces

  • Ingestion via OpenTelemetry
  • SDKs for Python and JavaScript or TypeScript
  • Public REST API
  • Scheduled export to S3, Google Cloud Storage or Azure Blob Storage in Parquet, CSV, JSON or JSONL
  • Export from the interface as CSV, JSON or JSONL

Matching methods

Sources

  1. 1.Plans, included units, retention periods, overage tiers, add-on and audit logging only in the top plan (opens in a new tab)langfuse.com/pricing · As of 2026-07-30
  2. 2.Certifications, encryption, penetration testing, available regions (opens in a new tab)langfuse.com/security · As of 2026-07-30
  3. 3.EU region in Ireland on AWS eu-west-1, full separation between regions, switching only via a new account and a migration of your own (opens in a new tab)langfuse.com/security/data-regions · As of 2026-07-30
  4. 4.No training on client data, retention configurable per project, data processing agreement available (opens in a new tab)langfuse.com/security/privacy-faq · As of 2026-07-30
  5. 5.Data processing addendum with EU standard contractual clauses incorporated, version dated 10 April 2026 (opens in a new tab)clickhouse.com/legal/agreements/data-processing-addendum · As of 2026-07-30
  6. 6.Full list of subprocessors and group affiliates, dated 10 April 2026 (opens in a new tab)clickhouse.com/legal/agreements/langfuse-subprocessors · As of 2026-07-30
  7. 7.For pay-as-you-go billing the contracting party is Langfuse GmbH; governing law is Delaware (opens in a new tab)clickhouse.com/legal/clickhouse-general-terms-and-conditions · As of 2026-07-30
  8. 8.Acquisition by ClickHouse on 16 January 2026, commitment to continue under the MIT licence and to keep self-hosting available (opens in a new tab)clickhouse.com/… · As of 2026-07-30
  9. 9.Legal entity Langfuse GmbH, Charlottenburg local court HRB 248821B, managing directors Aaron Katz and Clemens Rawert (opens in a new tab)langfuse.com/imprint · As of 2026-07-30
  10. 10.MIT core without limits; audit logs, masking, retention policies, project-level roles and SCIM require a licence key (opens in a new tab)langfuse.com/self-hosting/license-key · As of 2026-07-30
  11. 11.Scheduled export of traces, observations and scores in Parquet, CSV, JSON or JSONL (opens in a new tab)langfuse.com/…/export-to-blob-storage · As of 2026-07-30
  12. 12.Vendor adoption figures: GitHub stars, Docker pulls, monthly SDK installs, use across Fortune 50 and Fortune 500 companies (opens in a new tab)langfuse.com/about/about · As of 2026-07-30
  13. 13.clickhouse.com/… (opens in a new tab)As of 2026-07-30

Last reviewed: 2026-07-30 by Dr. Oliver Gausmann, Convios GmbH

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