Updated 13 Nov 2026 · prices read on vendor pages

9 best LangSmith alternatives in 2027

Reviewed by Mehmet Elmicenni, founder of Zekai•Prices checked 13 Nov 2026•How we check

The short answer

The best LangSmith alternatives in 2027 are Braintrust (best overall, $249/mo), Langfuse (best free plan: 50k units a month, 2 users) and Opik (best open source, Apache-2.0). LangSmith itself starts at $39/seat/mo. Zekai checked these prices on vendor pages on 13 Nov 2026; 6 more are compared below, including 1 with a free plan and 4 open source.

Open the Zekai Cost Finder Get price alerts

Best overallSee in table →

Braintrust

$249/mo · free plan

8.0

Best free planSee in table →

Langfuse

Free to self-host · MIT

7.9

Best open sourceSee in table →

Opik

Free to self-host · Apache-2.0

8.2

9alternatives compared

2with a free plan

6open source

$19/mo (hosted)cheapest paid · Opik

$39/seat/moLangSmith starts at

01 · Zekai Price Ledger

Which LangSmith alternatives are worth it in 2027?

The strongest LangSmith alternatives for LLM tracing and evals are Langfuse, Braintrust, Opik, Arize Phoenix, Helicone, W&B Weave, Laminar, Lunary and Datadog Agent Observability. Langfuse, Opik, Helicone, Weave and Laminar publish open-source code, Braintrust charges $249 a month flat, and LangSmith Plus is $39 per seat.

Zekai Cost Finder · team1 person

Tool	Type	Starting price	Free plan limit	Best for	Cost for your team	Checked
LangSmithThe tool you are replacing	You are here	$39/seat/moPlus, $39 per seat per month (page shows monthly self-serve billing only; usage after 10k base traces billed in LSU at $1.00)	5k base traces a month, 1 seat	Tracing and evals for LangChain and LangGraph apps	—	13 Nov 2026	Pricing ↗
Langfuse Zekai score 7.9Best free plan	Open source	$29/mo (hosted)Core Cloud, $29/mo (no yearly toggle on the page); Pro $199/mo	No limit, self-hosted (MIT)	Self-hosted tracing with flat pricing	—	13 Nov 2026	Pricing ↗
Braintrust Zekai score 8.0Best overall	Free plan + paid	$249/moPro, $249/mo flat (page shows no yearly toggle); includes $100 model credits, 5 GB processed data, 50k scores, 30-day retention	Starter: $10 model credits, 1 GB processed data, 10k scores, 14-day retention, unlimited users	Eval-first teams shipping prompts weekly	—	13 Nov 2026	Pricing ↗
Opik Zekai score 8.2Best open source	Open source	$19/mo (hosted)Pro Cloud, $19 per month (page shows a single monthly figure)	No limit, self-hosted (Apache-2.0)	Cheapest hosted tracing plus open source	—	13 Nov 2026	Pricing ↗
Datadog Agent Observability Zekai score 8.1Cheapest paid	Free plan + paid	$160/moPro, $160/mo billed annually or $200/mo month-to-month ($240 on-demand)	Free: 40K LLM spans a month, 15-day trace retention	Teams already monitoring infrastructure on Datadog	—	13 Nov 2026	Pricing ↗
Arize Phoenix Zekai score 8.3	Open source	$50/mo (hosted)AX Pro (hosted), $50 per month (page shows a single monthly figure); Phoenix OSS itself is $0	No limit, self-hosted (Elastic-2.0 (not OSI-approved))	OpenTelemetry-native tracing you can run locally	—	13 Nov 2026	Pricing ↗
Helicone Zekai score 6.8	Open source	$79/mo (hosted)Pro, $79 per month plus usage-based pricing (7-day free trial; page shows a single monthly figure); Team $799/mo	No limit, self-hosted (Apache-2.0)	Proxy-style request logging with gateway caching	—	13 Nov 2026	Pricing ↗
W&B Weave Zekai score 7.8	Open source	$60/mo (hosted)Pro, starts at $60 per month billed monthly (Weights & Biases pricing, now shown under CoreWeave Forge); 30-day free trial	No limit, self-hosted (Apache-2.0)	Teams that also track model training runs	—	13 Nov 2026	Pricing ↗
Laminar Not yet reviewed by Zekai	Open source	$30/mo (hosted)Starter, $30 per month (page shows a single monthly figure); Pro $150/mo	No limit, self-hosted (Apache-2.0)	Agent trace search with browser session recording	—	13 Nov 2026	Pricing ↗
Lunary Not yet reviewed by Zekai	Paid	$20/user/moTeam, $20 per user per month, billed monthly; 50,000 events included then $10 per 50k	No free plan	Small teams wanting prompt management and human reviews	—	13 Nov 2026	Pricing ↗

Every price was read on the vendor's own pricing page on the date shown. The Cost Finder assumes one entry plan per person, so it multiplies by your team size; yearly prices are shown per month, and team or business plans can cost more per seat. "Not checked" means we could not confirm a public price.

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02 · Free plan

Is there a free version of LangSmith?

Yes. LangSmith's Developer plan costs $0 per seat per month and includes 1 seat and up to 5k base traces a month, with pay-as-you-go usage after that, per langchain.com/pricing. Plus adds unlimited seats at $39 each and includes 10k base traces a month. Startups can apply for credits of up to $10,000.

Source: LangSmith pricing page, read 13 Nov 2026.

Free$0

5k base traces a month, 1 seat

Paid from$39/seat/mo

Plus, $39 per seat per month (page shows monthly self-serve billing only; usage after 10k base traces billed in LSU at $1.00)

03 · Free alternatives

What are the best free LangSmith alternatives?

Free LangSmith alternatives include Langfuse Hobby (50k units, 2 users), Opik Free Cloud (25k spans, 10 members), Arize AX Free (25k spans, unlimited users), Braintrust Starter (10k scores, unlimited users), Datadog Free (40K LLM spans) and Laminar Free (1 GB). LangSmith Developer is limited to 1 seat and 5k base traces.

Braintrust

Best overallFree plan + paid

Starter: $10 model credits, 1 GB processed data, 10k scores, 14-day retention, unlimited users

Paid from $249/mo

vs LangSmith →Zekai review

Datadog Agent Observability

Cheapest paidFree plan + paid

Free: 40K LLM spans a month, 15-day trace retention

Paid from $160/mo

vs LangSmith →Zekai review

04 · Open source

What are the best open-source LangSmith alternatives?

Open-source LangSmith alternatives are Langfuse (MIT, with separately licensed ee/ folders), Opik, Helicone, W&B Weave and Laminar (all Apache-2.0). Arize Phoenix is source-available under Elastic License 2.0, which is not an OSI-approved open-source licence. Helicone's pricing page says it is now part of Experiential Labs.

Langfuse

MIT★ 37.4k GitHub stars · Nov 2026

To self-host: Docker Compose, Kubernetes (Helm) or Terraform for AWS, GCP and Azure, per the pricing page; ClickHouse-backed. Enterprise ee/ folders sit under a separate licence file.

Last release 12 Nov 2026

Zekai open-source page Source code ↗Managed hosting slot

Opik

Apache-2.0★ 23.4k GitHub stars · Nov 2026

To self-host: Comet's pricing page lists a free open-source download using the same codebase as the hosted plans; the repo is Apache-2.0 and the docs cover running it on your own servers.

Last release 6 Nov 2026

Zekai open-source page Source code ↗Managed hosting slot

Arize Phoenix

Elastic-2.0 (not OSI-approved)★ 12.3k GitHub stars · Nov 2026

To self-host: Arize's pricing page describes Phoenix as open-source, local-first software for tracing, evaluation, experimentation and prompt iteration; the AX hosted product is separate and SaaS-only below Enterprise.

Last release 11 Nov 2026

Zekai open-source page Source code ↗Managed hosting slot

Helicone

Apache-2.0★ 6.3k GitHub stars · Nov 2026

To self-host: The repo is Apache-2.0; the pricing page lists on-prem deployment only under Enterprise. Helicone's pricing page says it is now part of Experiential Labs, and the last GitHub release is dated 2025-08-21.

Last release 21 Aug 2025

Zekai open-source page Source code ↗Managed hosting slot

W&B Weave

Apache-2.0★ 1.1k GitHub stars · Nov 2026

To self-host: The weave client in the repo is Apache-2.0; tracing data is stored in W&B's hosted service on the Free and Pro plans, and the pricing page lists customer-managed options only under Enterprise.

Last release 5 Nov 2026

Zekai open-source page Source code ↗Managed hosting slot

Laminar

Apache-2.0

To self-host: The lmnr repo carries an Apache-2.0 LICENSE; Laminar's pricing page lists on-premise only under Enterprise, so check the repo docs for the self-host stack.

Last release 10 Nov 2026

Source code ↗Managed hosting slot

05 · Side by side

How does LangSmith compare with each alternative?

LangSmith charges $39 per seat on Plus plus per-trace usage. Opik Pro is $19 a month, Lunary Team $20 per user, Laminar Starter $30, Langfuse Core $29, Arize AX Pro $50, W&B Pro from $60, Helicone Pro $79, Datadog Pro $160 billed annually and Braintrust Pro $249 flat. Each entry compares limits, units and licence.

LangSmith vs Langfuse

Best free planOpen source$29/mo (hosted) · checked 13 Nov 20267.9

The differencePaid plans bill per usage unit (100k units included, then $8 per 100k) with unlimited users from $29/mo, whereas LangSmith Plus charges $39 per seat plus per-trace overage; Langfuse can also be self-hosted.

Switch to Langfuse ifyour team has many seats but modest trace volume and wants flat monthly pricing or self-hosting

Stay with LangSmith ifyou already build on LangGraph and want Fleet, Sandboxes and Agent Server deployment inside one vendor

Visit Langfuse Read the Zekai review Price alert

LangSmith vs Braintrust

Best overallFree plan + paid$249/mo · checked 13 Nov 20268.0

The differenceStarter gives unlimited users and projects at $0, but meters scores (10k a month) and processed data (1 GB) instead of traces; LangSmith Developer is limited to 1 seat.

Switch to Braintrust ifseveral engineers and PMs must share one eval workspace and you want to avoid per-seat charges

Stay with LangSmith ifyou want a small trace-based bill at $39 per seat rather than a $249 flat Pro fee

Pros

Free Starter plan with no credit card required
Unlimited users, projects, datasets, playgrounds and experiments on every plan

Cons

Starter keeps data for only 14 days
Overage billed per GB ($4 on Starter) and per 1,000 scores

Pros and cons from the Zekai review of Braintrust · Verdict: LLM evals and tracing

Visit Braintrust Read the Zekai review Price alert

LangSmith vs Opik

Best open sourceOpen source$19/mo (hosted) · checked 13 Nov 20268.2

The differencePro Cloud costs $19 a month for up to 50 team members and 100k spans; the OSS build is Apache-2.0 and adds Test Suites with assertions and an Agent Playground.

Switch to Opik ifyou need a low fixed monthly bill for a large team and want a permissively licensed self-host option

Stay with LangSmith ifyou rely on LangSmith Fleet, Sandboxes or Engine for agent deployment beyond tracing and evals

Visit Opik Read the Zekai review Price alert

LangSmith vs Datadog Agent Observability

Cheapest paidFree plan + paid$160/mo · checked 13 Nov 20268.1

The differenceBills only on LLM spans (100K a month in Pro) and links agent traces to backend services, infrastructure and real user sessions; LangSmith meters all base traces.

Switch to Datadog Agent Observability ifyour backend is already monitored in Datadog and you want agent traces beside infrastructure and session data

Stay with LangSmith ifyou only need LLM tracing and datasets and do not want an infrastructure monitoring contract

Pros

Comprehensive observability across infrastructure, logs, and applications
Integrated cloud security and compliance tools

Cons

Certain products are unavailable on specific deployment sites like US-FED
Costs can scale quickly based on data volume and feature adoption

Pros and cons from the Zekai review of Datadog Agent Observability · Verdict: Unified Monitoring Platform

Visit Datadog Agent Observability Read the Zekai review Price alert

LangSmith vs Arize Phoenix

Open source$50/mo (hosted) · checked 13 Nov 20268.3

The differencePhoenix is source-available under Elastic License 2.0, which is not OSI-approved, and the hosted AX Pro plan is $50 a month with unlimited users and unlimited evals, against LangSmith's per-seat $39.

Switch to Arize Phoenix ifyou want unlimited users and evals on a $50 flat hosted plan, or a local-first tracing tool you can run from a notebook

Stay with LangSmith ifyour agents run on LangGraph and you want Agent Server deployment and Sandboxes from the same vendor as tracing

Visit Arize Phoenix Read the Zekai review Price alert

LangSmith vs Helicone

Open source$79/mo (hosted) · checked 13 Nov 20266.8

The differenceCounts requests rather than traces (10,000 free) and includes a gateway with caching, rate limits and automatic fallbacks; Pro has unlimited seats at $79 a month plus usage.

Switch to Helicone ifyou want a request-logging gateway with caching and provider fallbacks and a flat team price instead of per-seat billing

Stay with LangSmith ifyou need full agent trace trees, online evaluators and annotation queues from the tool you already use for LangChain apps

Visit Helicone Read the Zekai review Price alert

LangSmith vs W&B Weave

Open source$60/mo (hosted) · checked 13 Nov 20267.8

The differenceSits beside W&B experiment tracking, artifacts and model registry, with Weave data ingestion metered in GB (1 GB free) and extra ingestion at $0.10 per MB on Free.

Switch to W&B Weave ifyour team already tracks training runs in Weights & Biases and wants agent traces and evals in the same workspace

Stay with LangSmith ifyou need trace-count pricing, Fleet or Agent Server deployment rather than data-volume metering

Visit W&B Weave Read the Zekai review Price alert

LangSmith vs Laminar

Open source$30/mo (hosted) · checked 13 Nov 2026

The differencePrices by GB of trace data ($2 per GB over 3 GB on Starter) and records browser sessions beside traces; Starter has unlimited seats and projects, unlike LangSmith's per-seat billing.

Switch to Laminar ifyou run browser-using agents and want session recordings plus unlimited seats on a $30 Starter plan

Stay with LangSmith ifyou need LangGraph Studio, prompt hub and the 5k-trace Developer plan with community support

Visit Laminar Price alert

LangSmith vs Lunary

Paid$20/user/mo · checked 13 Nov 2026

The differenceTeam plan is $20 per user with 50,000 events a month, 300 AI Playground queries and 1-year history; self-hosting is listed only under Enterprise, and the page shows no free plan for new workspaces.

Switch to Lunary ifyou want a cheaper per-seat price than $39 and need chat replays, topic classification and human reviews for a small team

Stay with LangSmith ifyou want a free Developer plan to start on and trace-based pricing with LangGraph-native deployment

Visit Lunary Price alert

06 · What changed

Why do people leave LangSmith?

2 Nov 2026
Workspaces now have an hourly cap on persisted bytes, defaulting to 100 GB, and ingestion is rejected once a workspace exceeds it. (source)
26 Oct 2026
Multipart and OTel batch ingestion now enforce short-term usage limits, so over-limit traces receive an HTTP 429 response. (source)
13 Nov 2026
Usage across LangSmith products is metered in LangChain Standard Units at $1.00 per LSU, with extra traces billed at 0.005 LSU each after the included base traces. (source)

08 · FAQ

Questions people ask about LangSmith alternatives

What is the best alternative to LangSmith in 2027?

Braintrust is the best overall LangSmith alternative on this page ($249/mo). For no cost, Langfuse has a free plan (Hobby: 50k units a month, 2 users, 30 days data access). To self-host, Opik is open source (Apache-2.0).

Is there a free version of LangSmith?

Yes. LangSmith has a free plan: 5k base traces a month, 1 seat. Paid plans start at $39/seat/mo, checked on 13 Nov 2026.

Is there a 100% free alternative to LangSmith?

Yes. Langfuse, Opik, Arize Phoenix, Helicone, W&B Weave, Laminar are open source and free to self-host. Braintrust, Datadog Agent Observability have a free plan with limits, shown in the table.

What is cheaper than LangSmith?

Datadog Agent Observability starts at $160/mo, against $39/seat/mo for LangSmith, as listed on each vendor's pricing page on 13 Nov 2026.

How much do LangSmith alternatives cost for a team of 5?

If each of 5 people buys the entry paid plan, at the prices Zekai checked on 13 Nov 2026, the monthly cost is Opik $95/mo, Lunary $100/mo, Langfuse $145/mo, against LangSmith $195/mo for LangSmith. Team and business plans can cost more per seat. The Zekai Cost Finder on this page recalculates for any team size.

Which is better, Braintrust or LangSmith?

Starter gives unlimited users and projects at $0, but meters scores (10k a month) and processed data (1 GB) instead of traces; LangSmith Developer is limited to 1 seat. Choose Braintrust if several engineers and PMs must share one eval workspace and you want to avoid per-seat charges. Stay with LangSmith if you want a small trace-based bill at $39 per seat rather than a $249 flat Pro fee.

Why are people leaving LangSmith?

The documented reasons are: Workspaces now have an hourly cap on persisted bytes, defaulting to 100 GB, and ingestion is rejected once a workspace exceeds it (2 Nov 2026); Multipart and OTel batch ingestion now enforce short-term usage limits, so over-limit traces receive an HTTP 429 response (26 Oct 2026). Each is sourced in the section above.

What is the best LangSmith alternative?

Langfuse is the most searched rival and is open source with a free cloud tier. Braintrust suits eval-heavy teams, Opik and Laminar are low-cost hosted options, and Datadog suits teams already using it.

09 · Method

How did Zekai check this page?

Zekai independently reviews AI tools. For this page we read each vendor's own pricing and product pages and recorded the starting price, the free-plan limit and the date of the check. Only tools that do the same job as LangSmith are listed, and sponsors never change the order or the scores.

Mehmet Elmicenni

Founder of Zekai. Reviews the alternatives pages and the price checks behind them.

About the founder · How Zekai scores tools

1 · Same job onlyEvery alternative does the same task as LangSmith; tools for other jobs are left out.

2 · Vendor pages onlyPrices and free limits come from each vendor's own pricing page, never from blogs.

Zekai score0–10, from four published weights: ease 25%, output quality 30%, value 20%, time saved 25%. How we score

3 · Re-checkedA price older than 35 days is re-read or the page falls back to an older version.

Change log

13 Nov 2026
Page rebuilt on v6 with nine alternatives; all vendor pricing pages re-read.

9 best LangSmith alternatives in 2027

Braintrust

Langfuse

Opik

Which LangSmith alternatives are worth it in 2027?

Know first when LangSmith or an alternative changes price

Your tool here

Is one of these tools yours?

Is there a free version of LangSmith?

What are the best free LangSmith alternatives?

Braintrust

Datadog Agent Observability

What are the best open-source LangSmith alternatives?

Langfuse

Opik

Arize Phoenix

Helicone

W&B Weave

Laminar

How does LangSmith compare with each alternative?

LangSmith vs Langfuse

LangSmith vs Braintrust

LangSmith vs Opik

LangSmith vs Datadog Agent Observability

LangSmith vs Arize Phoenix

LangSmith vs Helicone

LangSmith vs W&B Weave

LangSmith vs Laminar

LangSmith vs Lunary

Why do people leave LangSmith?

More comparisons for LLM observability and evals

Questions people ask about LangSmith alternatives

What is the best alternative to LangSmith in 2027?

Is there a free version of LangSmith?

Is there a 100% free alternative to LangSmith?

What is cheaper than LangSmith?

How much do LangSmith alternatives cost for a team of 5?

Which is better, Braintrust or LangSmith?

Why are people leaving LangSmith?

What is the best LangSmith alternative?

How did Zekai check this page?