LangSmith vs Archal vs Langfuse: 2026 Comparison Guide

Compare LangSmith, Archal, and Langfuse at a glance

For a broader view of how these three stack up against other tools in the category, see our AI Agent Observability & Evaluation comparisons hub.

What is LangSmith?

LangSmith is LangChain's observability and evaluation platform for LLM applications and agents. It covers tracing, prompt management, a playground, datasets and experiments, human annotation queues, and an LLM gateway, according to its feature documentation. It also offers agent deployment and hosting through "Dev Fleet" agents, a capability neither Archal nor Langfuse publishes in this comparison. LangSmith supports self-hosted and hybrid deployment on its Enterprise plan, alongside cloud-hosted options. It targets teams already building with LangChain or LangGraph, though its SDKs are multi-language and OpenTelemetry-compatible, so it is not strictly limited to that ecosystem.

What is Archal?

Archal describes itself as "the improvement loop for AI agents." It is a Y Combinator company (per its YC profile) built around sandboxed, disposable test environments where teams can run agents against markdown-based test scenarios that get scored 0 to 100. Archal supports tracing, evaluation, CI/CD integration, and multi-language SDKs, per its documented feature set. It does not document prompt management, a playground, dataset/experiment tooling, production monitoring, or self-hosting, and its compliance posture (GDPR, SOC 2, SSO) is not published as of this comparison's verification date. As a 2026-founded, 2-employee company, it targets teams that want a fast, low-commitment way to test and refine agent behavior before or alongside production use.

What is Langfuse?

Langfuse is an open-source LLM engineering platform covering tracing, prompt management, evaluation, datasets and experiments, a playground, and production monitoring. It is self-hostable and open source, the only tool of the three with both attributes confirmed. Langfuse documents OpenTelemetry integration, human annotation queues, and CI/CD-gated experiments explicitly, with published docs walking through how to gate deployments on experiment results. Its "LLM Gateway" capability routes through the third-party LiteLLM integration rather than a natively built gateway. Langfuse's security page confirms GDPR, SOC 2, ISO 27001, and a HIPAA-ready data region on Langfuse Cloud, positioning it toward teams that want compliance coverage without giving up open-source flexibility.

LangSmith: pros and cons

Pros

Agent deployment and hosting is built in. LangSmith's Dev Fleet agents let teams run and host agents directly on the platform, a feature the feature matrix does not credit to either Archal or Langfuse. The free Developer plan includes one Dev Fleet agent with 50 runs/month, and Plus adds unlimited Fleet agents with 500 runs/month included.

Compliance coverage is the broadest of the three. LangSmith confirms GDPR, SOC 2, ISO 27001, and HIPAA compliance, plus custom SSO, ABAC, and RBAC on Enterprise. For teams in regulated industries, this removes a research step that Archal currently leaves open.

The free Developer tier is feature-rich, not a stripped demo. At $0/seat/month it includes prompt management, a playground, datasets and experiments, human annotation queues, and an LLM gateway, per the feature matrix, alongside 5,000 base traces/month before pay-as-you-go usage kicks in.

Cons

Usage-based add-ons stack on top of seat pricing. Beyond the seat fee, LangSmith bills LangChain Compute Units at $1.50/LCU, Storage Units at $1.00/LSU, base traces (14-day retention) at $2.50/1,000 beyond the plan allowance, and extended traces (400-day retention) at $5.00/1,000. Enterprise pricing itself is not published; it requires contacting sales for a custom annual quote.

No first-class CI/CD integration is documented. Unlike Langfuse, which publishes explicit docs for gating experiments in CI/CD pipelines, LangSmith does not have an equivalent first-class feature documented as of this comparison. That does not confirm the absence of any CI/CD path, only that none is documented.

Large datasets strain the interface. Product Hunt reviewer Hannah Craighead noted that "the UI can be tricky to work with for larger datasets or datasets with a large experiment history," a limitation worth testing against your own data volume before committing.

Archal: pros and cons

Pros

Sandboxes are billed by the second, not the seat. At $0.10 per environment-minute, prorated to the second, teams pay only for active test time. Failed provisioning and cold-start time are excluded from billing entirely, which keeps iterative testing cheap compared to a flat monthly subscription.

Signup credit removes the initial cost barrier. New accounts get $5 in free credit on verified signup and $15 more once the first sandbox starts, with no card required. That is enough runway to validate whether Archal's sandbox model fits an agent-testing workflow before spending anything.

CI/CD integration and scenario-based scoring fit an improvement-loop workflow. Archal's markdown-based test scenarios, scored 0 to 100, plug into CI/CD pipelines and support multi-language SDKs, making it straightforward to gate agent changes on measurable scores rather than manual review alone.

Cons

Compliance status is unverified, not confirmed absent. GDPR, SOC 2, and SSO/SAML are not documented on archal.ai or docs.archal.ai as of the verification date. Teams with compliance requirements should treat this as an open question to ask Archal directly, not assume either way.

The feature set is narrower than LangSmith or Langfuse. Archal does not document prompt management, dataset/experiment tooling, a playground, or production monitoring, per the feature matrix. It is built for testing and improvement loops, not as a full observability replacement.

There is no independent review record yet. No public reviews for Archal turned up on G2, Capterra, Trustpilot, or Product Hunt at the time of research, consistent with a company founded in 2026 with two employees. That means there is no outside user feedback to weigh against the vendor's own claims yet.

Langfuse: pros and cons

Pros

Open source and self-hostable, with no exceptions by tier. Langfuse is the only tool here confirmed as both open source and self-hostable at every plan level, per its feature matrix, which matters for teams that want to avoid vendor lock-in or run entirely within their own infrastructure.

The free tier is genuinely usable, and Core is flatly priced. Hobby includes 50,000 units/month, 30-day data access, and 2 users at $0. Core steps up to $29/month org-wide with unlimited users and 100,000 units/month included, with additional usage at $8/100k units.

CI/CD-gated experiments are explicitly documented. Langfuse publishes dedicated docs on running experiments in CI/CD pipelines, a first-class workflow the feature matrix does not credit to LangSmith, useful for teams that want to block deployments on evaluation regressions automatically.

Cons

Complex agent debugging may hit a ceiling. Product Hunt reviewer Nolan Vu, in the critical portion of an otherwise positive review, noted that "tracing and prompt versioning features are solid, but complex agent debugging might push you to look elsewhere eventually."

SSO and RBAC require an add-on at the Pro tier. Enterprise-grade SSO and RBAC are bundled into Pro only via a +$300/month Teams add-on, on top of the $199/month Pro price, rather than being included outright below the Enterprise plan.

The LLM gateway is a third-party integration, not a native build. Langfuse's gateway routing runs through the LiteLLM integration rather than a gateway built natively by Langfuse, worth knowing if you need gateway-specific support directly from Langfuse's own team.

Use-case comparison

Solo developers and early-stage teams prototyping agents. Archal's pay-as-you-go pricing and signup credits mean you can start testing without a subscription decision, and LangSmith's free Developer plan and Langfuse's Hobby plan both cover small-scale tracing at $0. If your priority is fast iteration on agent behavior specifically, Archal's sandbox-and-score loop is the more purpose-built fit; if you need broader tracing plus prompt management from day one, Langfuse's Hobby plan covers more ground for free.

Teams needing compliance-ready production deployment. LangSmith and Langfuse both confirm GDPR, SOC 2, and ISO 27001, with LangSmith adding documented HIPAA compliance and Langfuse offering a HIPAA-ready Cloud region. Archal has not published any compliance certifications, so regulated teams should treat it as unverified until Archal confirms otherwise directly.

Teams building iterative agent-improvement loops with CI/CD gates. Archal's scenario-based scoring (0-100) and Langfuse's documented CI/CD experiment gating both target this workflow directly, while LangSmith does not document a first-class CI/CD integration. If self-hosting or open-source access matters alongside CI/CD gating, Langfuse is the closer match; if disposable, per-second-billed sandboxes matter more, Archal fits that narrower need.

LangSmith pricing

LangSmith runs three tiers, plus usage add-ons that apply across all of them.

• Developer: $0/seat/month, capped at 1 seat, includes 5,000 base traces/month then pay-as-you-go, and 1 Dev Fleet agent with 50 runs/month.
• Plus: $39/seat/month, up to 10 seats, 10,000 base traces/month included then pay-as-you-go, and unlimited Fleet agents with 500 runs/month included.
• Enterprise: pricing not published; custom, invoiced annually, reached through contact sales. Includes self-hosted and hybrid deployment, custom SSO/ABAC/RBAC, and a support SLA.
• Usage add-ons across all plans: LangChain Compute Units at $1.50/LCU, LangChain Storage Units at $1.00/LSU, base traces (14-day retention) at $2.50/1,000 beyond allowance, and extended traces (400-day retention) at $5.00/1,000.

Pricing verified on August 5, 2026.

Archal pricing

Archal has no published tiered or subscription pricing; archal.ai/pricing was not live as of verification, so the only confirmed model is usage-based.

• Pay-as-you-go: $0.10 per environment-minute, billed prorated to the second. New signups receive $5 in free credit on verified signup plus $15 more when the first sandbox starts, no card required. Failed provisioning and cold-start time are not billed.

Secondary sources mention a possible $199/seat "Teams" plan and a "SOC 2 in progress" Enterprise tier, but neither could be confirmed on archal.ai or docs.archal.ai, so they are excluded here rather than stated as fact.

Pricing verified on August 5, 2026.

Langfuse pricing

Langfuse publishes four tiers, billed org-wide rather than per seat on every plan except where noted.

• Hobby: $0/month, 50,000 units/month included, 30-day data access, 2 users, community support.
• Core: $29/month org-wide with unlimited users, 100,000 units/month included, 90-day data access, additional usage at $8/100k units, billed monthly.
• Pro: $199/month org-wide with unlimited users, same included usage as Core, 3-year data access, SOC 2 Type II and ISO 27001 reports available, unlimited annotation queues, higher rate limits. An optional Teams add-on at +$300/month adds Enterprise SSO/RBAC.
• Enterprise: $2,499/month, with custom pricing available under a yearly commitment. Includes everything in Pro plus Teams, audit logs, a SCIM API, custom rate limits, an uptime SLA, and a dedicated support engineer.

Pricing verified on August 5, 2026.

What users say

LangSmith

"Since bringing LangSmith in, we've been able to trace problems through the entire prompt path and actually understand what's going on." - Dan Bulteel, Meet-Ting founder, via Product Hunt

"We absolutely could not build this product with LangSmith for traces, datasets, annotation queues, and evals." - Kyle Rush, Astrid builder, via Product Hunt

"The UI can be tricky to work with for larger datasets or datasets with a large experiment history." - Hannah Craighead, via Product Hunt

LangSmith holds a 4.8-star average from 19 ratings on Product Hunt as of the verification date.

Archal

No public reviews for Archal were found on G2, Capterra, Trustpilot, or Product Hunt as of August 5, 2026. That is consistent with a company that came out of Y Combinator's 2026 batch with a two-person team, but it also means there is no independent user feedback yet to check the vendor's own claims against. Ask Archal for reference customers directly if outside validation matters to your evaluation.

Langfuse

"Langfuse has been indispensable for us in leveraging LLMs. Its detailed tracing provides unrivaled clarity, streamlining our debug times..." - Nolan Vu, via Product Hunt

"Langfuse made it super easy for me to find & fix weird edge case responses of LLMs and build a new architecture that is much cheaper and more stable." - Nils Reichardt, via Product Hunt

"tracing and prompt versioning features are solid, but complex agent debugging might push you to look elsewhere eventually." - Nolan Vu, via Product Hunt

Langfuse holds a 5-star average from 48 ratings on Product Hunt as of the verification date.

Verdict per use case

Choose LangSmith if you are already building on LangChain or LangGraph, need agent deployment and hosting alongside observability, and want documented HIPAA, SOC 2, and ISO 27001 compliance without waiting on a vendor to confirm it. Budget for usage add-ons beyond the seat price, and expect to contact sales for Enterprise pricing.

Choose Archal if you want a low-commitment way to test and score agent behavior in disposable sandboxes, billed by the second rather than by seat or subscription, and you can accept that its compliance posture and broader feature set (prompt management, datasets, production monitoring) are not yet documented.

Choose Langfuse if open source and self-hosting matter, you want a genuinely usable free tier plus a flat $29/month step-up, and you need CI/CD-gated experiments documented as a first-class workflow rather than pieced together yourself.

Recap: LangSmith vs Archal vs Langfuse

If your evaluation also touches adjacent infrastructure decisions, our guides on Browserbase vs Steel vs Anchor Browser for agent browser tooling and RunPod vs Modal vs RightNow for the compute layer underneath your agents cover related stack choices. For how we handle sponsored placements and vendor relationships in comparisons like this one, see our editorial policy and how we make money.

Frequently asked questions