{
    "title": "LangSmith Alternatives 2027: 9 Paid, Free & Open-Source",
    "url": "https://zekaiwork.com/alternatives/langsmith/",
    "summary": "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.",
    "tool": {
        "name": "LangSmith",
        "starting_price": "$39/seat/mo",
        "free_plan": "5k base traces a month, 1 seat",
        "price_checked": "2026-11-13",
        "pricing_url": "https://www.langchain.com/pricing"
    },
    "task": "LLM observability and evals",
    "prices_checked": "2026-11-13",
    "date_modified": "2026-11-13",
    "alternatives": [
        {
            "name": "Langfuse",
            "type": "Open source",
            "starting_price": "$29/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "MIT",
            "best_for": "Self-hosted tracing with flat pricing",
            "difference": "Paid 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://langfuse.com/pricing",
            "website": "https://langfuse.com",
            "repository": "https://github.com/langfuse/langfuse",
            "zekai_open_source_page": "https://zekaiwork.com/free-open-source/langfuse/",
            "last_release": "2026-11-12",
            "zekai_score": 7.9,
            "zekai_review": "https://zekaiwork.com/free-open-source/langfuse/"
        },
        {
            "name": "Braintrust",
            "type": "Free plan + paid",
            "starting_price": "$249/mo",
            "free_plan_limit": "Starter: $10 model credits, 1 GB processed data, 10k scores, 14-day retention, unlimited users",
            "best_for": "Eval-first teams shipping prompts weekly",
            "difference": "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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://www.braintrust.dev/pricing",
            "website": "https://www.braintrust.dev",
            "zekai_score": 8,
            "zekai_review": "https://zekaiwork.com/ai-tools/braintrust/"
        },
        {
            "name": "Opik",
            "type": "Open source",
            "starting_price": "$19/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "Apache-2.0",
            "best_for": "Cheapest hosted tracing plus open source",
            "difference": "Pro 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://www.comet.com/site/pricing/",
            "website": "https://www.comet.com/site/products/opik/",
            "repository": "https://github.com/comet-ml/opik",
            "zekai_open_source_page": "https://zekaiwork.com/free-open-source/opik/",
            "last_release": "2026-11-06",
            "zekai_score": 8.2,
            "zekai_review": "https://zekaiwork.com/free-open-source/opik/"
        },
        {
            "name": "Datadog Agent Observability",
            "type": "Free plan + paid",
            "starting_price": "$160/mo",
            "free_plan_limit": "Free: 40K LLM spans a month, 15-day trace retention",
            "best_for": "Teams already monitoring infrastructure on Datadog",
            "difference": "Bills 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://www.datadoghq.com/pricing/?product=llm-observability",
            "website": "https://www.datadoghq.com/product/llm-observability/",
            "zekai_score": 8.1,
            "zekai_review": "https://zekaiwork.com/ai-tools/datadog/"
        },
        {
            "name": "Arize Phoenix",
            "type": "Open source",
            "starting_price": "$50/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "Elastic-2.0 (not OSI-approved)",
            "best_for": "OpenTelemetry-native tracing you can run locally",
            "difference": "Phoenix 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://arize.com/pricing/",
            "website": "https://phoenix.arize.com",
            "repository": "https://github.com/Arize-ai/phoenix",
            "zekai_open_source_page": "https://zekaiwork.com/free-open-source/arize-phoenix/",
            "last_release": "2026-11-11",
            "zekai_score": 8.3,
            "zekai_review": "https://zekaiwork.com/free-open-source/arize-phoenix/"
        },
        {
            "name": "Helicone",
            "type": "Open source",
            "starting_price": "$79/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "Apache-2.0",
            "best_for": "Proxy-style request logging with gateway caching",
            "difference": "Counts 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://www.helicone.ai/pricing",
            "website": "https://www.helicone.ai",
            "repository": "https://github.com/Helicone/helicone",
            "zekai_open_source_page": "https://zekaiwork.com/free-open-source/helicone/",
            "last_release": "2025-08-21",
            "zekai_score": 6.8,
            "zekai_review": "https://zekaiwork.com/free-open-source/helicone/"
        },
        {
            "name": "W&B Weave",
            "type": "Open source",
            "starting_price": "$60/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "Apache-2.0",
            "best_for": "Teams that also track model training runs",
            "difference": "Sits 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://wandb.ai/site/pricing/",
            "website": "https://wandb.ai/site/weave/",
            "repository": "https://github.com/wandb/weave",
            "zekai_open_source_page": "https://zekaiwork.com/free-open-source/wandb-weave/",
            "last_release": "2026-11-05",
            "zekai_score": 7.8,
            "zekai_review": "https://zekaiwork.com/free-open-source/wandb-weave/"
        },
        {
            "name": "Laminar",
            "type": "Open source",
            "starting_price": "$30/mo (hosted)",
            "free_plan_limit": "No limit (self-hosted)",
            "licence": "Apache-2.0",
            "best_for": "Agent trace search with browser session recording",
            "difference": "Prices 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://laminar.sh/pricing",
            "website": "https://laminar.sh",
            "repository": "https://github.com/lmnr-ai/lmnr",
            "last_release": "2026-11-10"
        },
        {
            "name": "Lunary",
            "type": "Paid",
            "starting_price": "$20/user/mo",
            "free_plan_limit": "No free plan",
            "best_for": "Small teams wanting prompt management and human reviews",
            "difference": "Team 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.",
            "price_checked": "2026-11-13",
            "pricing_url": "https://lunary.ai/pricing",
            "website": "https://lunary.ai"
        }
    ],
    "faq": [
        {
            "q": "What is the best alternative to LangSmith in 2027?",
            "a": "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)."
        },
        {
            "q": "Is there a free version of LangSmith?",
            "a": "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."
        },
        {
            "q": "Is there a 100% free alternative to LangSmith?",
            "a": "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."
        },
        {
            "q": "What is cheaper than LangSmith?",
            "a": "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."
        },
        {
            "q": "How much do LangSmith alternatives cost for a team of 5?",
            "a": "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."
        },
        {
            "q": "Which is better, Braintrust or LangSmith?",
            "a": "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."
        },
        {
            "q": "Why are people leaving LangSmith?",
            "a": "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."
        },
        {
            "q": "What is the best LangSmith alternative?",
            "a": "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."
        }
    ],
    "publisher": "Zekai (zekaiwork.com) — independently reviewed; prices read on vendor pages on the dates shown.",
    "licence": "Free to quote with a link to https://zekaiwork.com/alternatives/langsmith/. Bulk copying or republishing the dataset is not permitted."
}