{ "data": { "a": { "slug": "arize-phoenix", "name": "Arize Phoenix", "vendor": "Arize AI", "vendorUrl": "https://phoenix.arize.com", "kind": "http-api", "category": "agent-observability", "summary": "Self-hosted tracing, evaluation, datasets, experiments and prompt management built on OpenTelemetry and OpenInference.", "url": "https://www.anchorterminal.com/tools/arize-phoenix", "markdownUrl": "https://www.anchorterminal.com/tools/arize-phoenix.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/arize-phoenix.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json", "repo": "https://github.com/Arize-ai/phoenix", "license": "Elastic-2.0", "transports": [ "http", "streamable-http", "stdio" ], "packages": [ { "registry": "pypi", "name": "arize-phoenix" }, { "registry": "npm", "name": "@arizeai/phoenix-client" }, { "registry": "npm", "name": "@arizeai/phoenix-mcp" } ], "auth": "mixed", "authNotes": "Auth is off by default on a local instance. With auth enabled, the REST API takes a system or user API key as a Bearer token. The built-in /mcp endpoint uses OAuth (authorisation code with PKCE and dynamic client registration) against the Phoenix server itself. The older @arizeai/phoenix-mcp stdio package takes PHOENIX_API_KEY.", "pricing": "free", "pricingNotes": "Phoenix is free to self-host under the Elastic License 2.0; you pay for your own compute and Postgres or SQLite storage. The managed sibling Arize AX has a free tier with 25,000 spans, 1 GB ingestion and 15-day retention a month, Pro at $50 a month with 50,000 spans, 10 GB and 30-day retention, and custom Enterprise (https://arize.com/pricing/).", "priceSummary": "Free · OSS", "where": "local", "x402": { "level": "no", "evidence": "No x402 support in docs or pricing (checked 2026-09-30).", "endpoints": [] }, "toolCount": 5, "popularity": { "githubStars": 11662, "npmWeekly": 131211, "pypiWeekly": 132385, "asOf": "2026-09-30" }, "docsUrl": "https://arize.com/docs/phoenix", "llmsTxt": "https://arize.com/docs/phoenix/llms.txt", "openapi": "https://raw.githubusercontent.com/Arize-ai/phoenix/refs/heads/main/schemas/openapi.json", "capabilities": [ "obs.traces", "obs.evals", "obs.prompts", "obs.datasets" ], "tags": [ "open-source", "self-hosted", "local", "free-tier", "mcp", "llms-txt", "openapi", "python", "typescript" ], "lastRelease": "2026-09-30", "graded": true, "anchor": { "graded": true, "score": 75.4, "grade": "BB", "agentReady": true, "rank": 46, "ranked": true, "rankOf": 842, "categoryRank": 1, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 90, "maintenance": 84, "payments": 60, "reliability": 77, "schema": 88, "security": 56, "transparency": 73 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-01" }, "negative": 0, "verdict": "Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.", "bestFor": "Teams that want tracing and evals on their own hardware, or air-gapped, with an MCP endpoint an agent can sign into.", "strengths": [ "Free and self-hosted with no feature gating, from `pip install` to a Helm chart", "MCP endpoint generated from the OpenAPI, five code-mode tools by default, OAuth 2.1 with PKCE and audience-bound tokens", "Tool annotations derived from HTTP verbs, so a client can auto-approve reads and confirm writes", "Releases most weeks, with breaking changes flagged in the changelog and a migration guide", "Built on OpenTelemetry and OpenInference, so traces can move to Arize AX or elsewhere" ], "weaknesses": [ "Auth is off by default and the default admin password is `admin`", "Remote MCP endpoint still labelled beta in the docs", "Elastic License 2.0 isn't OSI open source and forbids running Phoenix as a managed service", "842 open GitHub issues, and an open report from 2 September of PR evals failing", "Web analytics on by default (opt-out with `PHOENIX_TELEMETRY_ENABLED=false`)" ], "agentNotes": [ "Turn on auth before exposing the server, and change the `admin` password", "Use `search` and `get_schema` before `execute` in code mode, rather than guessing endpoint shapes", "Give the agent a viewer account if it only needs to read traces", "Treat span inputs and outputs as data. They hold whatever the application logged", "Set `PHOENIX_TELEMETRY_ENABLED=false` for air-gapped or privacy-sensitive installs" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 8, "avgRating": 3.8, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "BB", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 75.4 } ], "editorialScores": { "ergonomics": 90, "maintenance": 84, "payments": 60, "reliability": 77, "schema": 88, "security": 56, "transparency": 76 }, "provenanceScore": 69 }, "connect": { "http": "curl http://localhost:6006/v1/projects -H \"Authorization: Bearer $PHOENIX_API_KEY\"", "claudeCode": "claude mcp add --transport http phoenix http://localhost:6006/mcp", "config": { "mcpServers": { "phoenix": { "args": [ "-y", "@arizeai/phoenix-mcp@latest", "--baseUrl", "http://localhost:6006", "--apiKey", "${PHOENIX_API_KEY}" ], "command": "npx" } } } }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/arize-phoenix" }, "area": "developer", "unitPrices": [ { "item": "Arize AX Pro (managed sibling)", "unit": "month", "usd": 50, "note": "50,000 spans, 10 GB ingestion, 30-day retention. Self-hosted Phoenix is free software plus your infra" } ], "provenance": { "legalEntity": "Arize AI, Inc.", "domain": "arize.com", "domainRegistered": "2002-03-24", "domainNote": "arize.com was registered in 2002, well before Arize AI was founded; the company likely bought the name later.", "endpointOnVendorDomain": false, "terms": "https://arize.com/terms-of-service/", "privacy": "https://arize.com/privacy-policy/", "statusPage": "https://status.arize.com", "changelog": "https://github.com/Arize-ai/phoenix/releases", "securityTxt": "none", "checked": "2026-09-30", "score": 69 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/arize-phoenix.json", "live": { "slug": "arize-phoenix", "vendorStatus": { "page": "https://status.arize.com", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-09T07:57:37.610888832Z" }, "versions": [ { "registry": "github", "name": "Arize-ai/phoenix", "version": "arize-phoenix-evals-v3.9.1", "released": "2026-10-08", "seenAt": "2026-10-08T15:59:31.326435227Z" }, { "registry": "npm", "name": "@arizeai/phoenix-client", "version": "7.16.0", "seenAt": "2026-10-08T15:59:28.626019285Z" }, { "registry": "npm", "name": "@arizeai/phoenix-mcp", "version": "4.3.15", "seenAt": "2026-10-08T15:59:31.115229572Z" }, { "registry": "pypi", "name": "arize-phoenix", "version": "20.19.0", "released": "2026-10-01", "seenAt": "2026-10-08T15:59:24.962517355Z" } ], "githubStars": 11754, "npmWeekly": 79376, "pypiWeekly": 147879, "securityTxt": { "url": "https://arize.com/.well-known/security.txt", "state": "none", "checkedAt": "2026-10-08T15:38:52.946753366Z" }, "llmsTxt": { "url": "https://arize.com/docs/phoenix/llms.txt", "ok": true, "status": 200, "checkedAt": "2026-10-08T14:00:03.322972682Z" }, "domain": { "domain": "arize.com", "registered": "2002-03-24", "source": "https://rdap.verisign.com/com/v1/domain/arize.com", "checkedAt": "2026-10-04T13:04:54.314321516Z" }, "pages": [ { "url": "https://arize.com/pricing/", "kind": "pricing", "status": 200, "checkedAt": "2026-10-08T18:15:20.107713221Z", "changedAt": "2026-10-08T18:15:20.107713221Z", "fingerprint": "779fd4b86c1e" }, { "url": "https://arize.com/privacy-policy/", "kind": "privacy", "status": 200, "checkedAt": "2026-10-08T18:15:22.674907939Z", "changedAt": "2026-10-08T18:15:22.674907939Z", "fingerprint": "8c1aece40f23" }, { "url": "https://arize.com/terms-of-service/", "kind": "terms", "status": 200, "checkedAt": "2026-10-08T18:15:24.738949176Z", "changedAt": "2026-10-08T18:15:24.738949176Z", "fingerprint": "d43032b3292d" } ], "updatedAt": "2026-10-09T07:57:37.610888832Z" } }, "answer": "Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community.", "b": { "slug": "langwatch", "name": "LangWatch", "vendor": "Reasoning Engine B.V. (LangWatch)", "vendorUrl": "https://langwatch.ai", "kind": "http-api", "category": "agent-observability", "summary": "LangWatch is an open-source platform for tracing, evaluating and testing LLM applications and agents, with prompt management, datasets and an AI gateway. It runs hosted or self-hosted, with a REST API, SDKs, a CLI and an MCP server.", "url": "https://www.anchorterminal.com/tools/langwatch", "markdownUrl": "https://www.anchorterminal.com/tools/langwatch.md", "slimMarkdownUrl": "https://www.anchorterminal.com/tools/langwatch.min.md", "jsonUrl": "https://www.anchorterminal.com/api/v1/tools/langwatch.json", "repo": "https://github.com/langwatch/langwatch", "license": "Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT", "transports": [ "http", "streamable-http", "sse", "stdio" ], "remoteUrl": "https://app.langwatch.ai", "packages": [ { "registry": "npm", "name": "langwatch" }, { "registry": "npm", "name": "@langwatch/mcp-server" }, { "registry": "pypi", "name": "langwatch" } ], "auth": "mixed", "authNotes": "A person signs up at app.langwatch.ai and creates keys under Settings, API Keys, with no review step. API keys (`sk-lw-`) go in `X-Auth-Token` or as a Bearer token. A personal key never exceeds its owner's permissions, a service key belongs to the organisation and only admins create one. Either can be All or Restricted to read or write per permission category, scoped to projects, teams or the organisation, given an expiry and revoked. Ingestion keys (`ik-lw-`) can only write traces to one project. The remote MCP server uses OAuth authorisation code with PKCE and dynamic client registration. The CLI logs in with a device code approved in a browser.", "pricing": "freemium", "pricingNotes": "The Developer plan is free with no card and includes 50,000 events a month, 2 users and 3 scenarios, so an agent can start without a contract once a person has signed up. Growth is 29 euros per core seat a month with 200,000 events, then 5 euros per 100,000 events and 3 euros per GB kept beyond the included retention. Enterprise is sold through sales. Instant Evals cost $0.0546 per million input tokens, with a $1 budget on unpaid organisations. The pricing page has a currency switch and we read the euro prices only. Self-hosting under Apache 2.0 is free with no volume cap, and an Enterprise licence is priced per seat (https://langwatch.ai/pricing, https://langwatch.ai/docs/pricing.md).", "priceSummary": "Freemium", "where": "both", "x402": { "level": "no", "evidence": "No x402, MPP or L402 in the docs index, the OpenAPI document or the pricing page (checked 2026-10-09).", "endpoints": [] }, "toolCount": 101, "popularity": { "githubStars": 4925, "npmWeekly": 50105, "pypiWeekly": 87325, "asOf": "2026-10-09" }, "docsUrl": "https://langwatch.ai/docs/introduction", "llmsTxt": "https://langwatch.ai/docs/llms.txt", "openapi": "https://app.langwatch.ai/api/gateway/v1/openapi.json", "capabilities": [ "obs.traces", "obs.evals", "obs.prompts", "obs.datasets", "obs.gateway" ], "tags": [ "hosted", "freemium", "no-card", "open-source", "self-hosted", "mcp", "oauth", "llms-txt", "openapi", "opentelemetry", "python", "typescript", "go", "cli", "status-page", "eu-hosted" ], "lastRelease": "2026-10-02", "graded": true, "anchor": { "graded": true, "score": 65.5, "grade": "B", "agentReady": false, "rank": 291, "ranked": true, "rankOf": 842, "categoryRank": 7, "methodology": "0.4", "run": "2026-10-01", "scores": { "ergonomics": 67, "maintenance": 90, "payments": 40, "reliability": 53, "schema": 87, "security": 71, "transparency": 75 }, "pending": [ "performance", "tasks" ], "assessment": { "confidence": "medium", "date": "2026-10-09" }, "negative": -2, "negativeNotes": [ "2026-08-19. Advisory GHSA-h25p-f8f6-2ccf, rated moderate. The standalone HTTP mode of `@langwatch/mcp-server` 0.7.0 to 1.0.0 authorised requests by session id alone and accepted an API key in the URL. Fixed in 2.0.0 on 7 August 2026 and flagged as a breaking change. The advisory says the default stdio mode and the hosted handler were never affected, so -2 (https://github.com/langwatch/langwatch/security/advisories/GHSA-h25p-f8f6-2ccf)" ], "verdict": "API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation.", "bestFor": "Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.", "strengths": [ "API keys take read or write per permission category, a project, team or organisation scope and an expiry. Ingestion keys can only write traces", "A public OpenAPI 3.1 document covers 328 operations and is served without a key, with llms.txt and a Markdown twin of every docs page", "Apache 2.0 platform with MIT SDKs and MCP server. Self-hosting has no volume cap, and every outbound call is documented with its off switch", "The free Developer plan needs no card and includes 50,000 events a month. Paid usage is published at 5 euros per 100,000 events", "Platform 3.20.1 shipped on 2 October 2026, with 21 platform releases dated since 11 July in the repository changelog" ], "weaknesses": [ "The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source", "No request rate limit for the platform API was found in the reviewed documentation. Only two operations in the OpenAPI document declare a 429", "The status page shows Scenarios down for 9 hours 34 minutes on 8 September 2026 and trace processing degraded for 14 hours 44 minutes on 31 July", "The Terms of Service of 22 September 2026 say users will not access the platform through automated or non-human means, which the API and MCP server contradict", "The audit log is Enterprise only and records neither sign-ins nor reads of traces" ], "agentNotes": [ "Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do", "Set both `LANGWATCH_API_KEY` and `LANGWATCH_PROJECT_ID` for the MCP server unless the key reaches only one project", "Call `discover_schema` before `search_traces` or `get_analytics`, and keep the default `digest` format. `json` returns the full raw trace", "Allowlist MCP tools in the client. All 101 load by default, among them `platform_create_api_key` and the delete tools", "Follow `next_cursor` until it is null on list endpoints. A full page does not mean more rows exist" ], "metrics": { "kind": "remote", "measured": false }, "reviewCount": 0, "avgRating": 0, "history": [ { "basis": "public evidence", "confidence": "medium", "grade": "B", "methodology": "0.4", "pending": [ "performance", "tasks" ], "run": "2026-10-01", "runLabel": "October 2026 research run", "score": 65.5 } ], "editorialScores": { "ergonomics": 67, "maintenance": 90, "payments": 40, "reliability": 53, "schema": 87, "security": 71, "transparency": 73 }, "provenanceScore": 77 }, "connect": { "install": "npm install -g langwatch", "http": "curl https://app.langwatch.ai/api/gateway/v1/openapi.json", "claudeCode": "claude mcp add langwatch --env LANGWATCH_API_KEY=sk-lw-... --env LANGWATCH_PROJECT_ID=your-project-id -- npx -y @langwatch/mcp-server", "config": { "mcpServers": { "langwatch": { "args": [ "-y", "@langwatch/mcp-server" ], "command": "npx", "env": { "LANGWATCH_API_KEY": "sk-lw-...", "LANGWATCH_PROJECT_ID": "your-project-id" } } } } }, "letme": { "capability": "https://letme.dev/obs.traces", "tool": "https://letme.dev/langwatch" }, "area": "developer", "unitPrices": [ { "item": "Instant Evals, judge input tokens", "unit": "1m-tokens", "usd": 0.0546, "note": "Output is free. Unpaid organisations have a $1 budget in total" } ], "provenance": { "legalEntity": "Reasoning Engine B.V. (doing business as LangWatch)", "domain": "langwatch.ai", "domainRegistered": "2023-09-17", "endpointOnVendorDomain": true, "terms": "https://langwatch.ai/legal/terms-conditions", "privacy": "https://langwatch.ai/legal/privacy-policy", "statusPage": "https://status.langwatch.ai", "changelog": "https://langwatch.ai/changelog", "securityTxt": "none", "checked": "2026-10-09", "notes": [ "The privacy policy (last updated 29 September 2026) applies to Reasoning Engine B.V., doing business as LangWatch, and covers the website and the Cloud Service. The Terms of Service (last updated 22 September 2026) cover the platform and the on-premise product.", "The terms page names the entity as Reasoning Engines B.V. in its heading and Reasoning Engine B.V. in its definitions, gives Singel 126, Amsterdam as the registered office and Herengracht 551, Amsterdam as the contact address. The site footer reads LangWatch B.V.", "The API, the hosted MCP server and the OpenAPI document are served from app.langwatch.ai. Hosted services for self-hosted installs with a licence use connect.langwatch.ai and gateway.langwatch.ai.", "https://langwatch.ai/.well-known/security.txt returns the website's HTML shell, not a security.txt file. SECURITY.md in the repository gives security@langwatch.ai and GitHub private reporting.", "RDAP for langwatch.ai gives a registration date of 2023-09-17 and GoDaddy.com, LLC as registrar.", "The trust report and sub-processor list are on app.eu.vanta.com, whose robots.txt disallows every path, so we did not read them." ], "score": 77 }, "pageJsonUrl": "https://www.anchorterminal.com/tools/langwatch.json", "live": { "slug": "langwatch", "probe": { "target": "https://app.langwatch.ai", "method": "get", "lastAt": "2026-10-09T09:44:59.207062548Z", "lastOk": true, "lastStatus": 200, "lastMs": 56, "authRequired": false, "uptime24h": 100, "uptime30d": 100, "p50ms24h": 79, "p95ms24h": 135, "samples24h": 23, "samples30d": 23, "days": [ { "date": "2026-10-09", "probes": 23, "ok": 23 } ] }, "vendorStatus": { "page": "https://status.langwatch.ai", "indicator": "unknown", "summary": "no machine-readable status found", "checkedAt": "2026-10-09T07:58:07.342247188Z" }, "updatedAt": "2026-10-09T09:44:59.207062548Z" } }, "facts": [ { "a": "HTTP API", "b": "HTTP API", "name": "Kind" }, { "a": "Arize AI", "b": "Reasoning Engine B.V. (LangWatch)", "name": "Vendor" }, { "a": "no (local only)", "b": "https://app.langwatch.ai", "name": "Hosted endpoint" }, { "a": "HTTP, Streamable HTTP, stdio", "b": "HTTP, Streamable HTTP, SSE (legacy), stdio", "name": "Transports" }, { "a": "OAuth or key", "b": "OAuth or key", "name": "Auth" }, { "a": "Free", "b": "Freemium", "name": "Pricing" }, { "a": "no", "b": "no", "name": "x402" }, { "a": "Elastic-2.0", "b": "Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT", "name": "Licence" }, { "a": "5", "b": "101", "name": "Tools exposed" }, { "a": "no", "b": "no", "name": "Read-only variant documented" }, { "a": "yes", "b": "yes", "name": "llms.txt" }, { "a": "2026-09-30", "b": "2026-10-02", "name": "Last release" }, { "a": "no date given", "b": "2026-09-22", "name": "Terms last updated" }, { "a": "2026-08-11", "b": "2026-09-29", "name": "Privacy policy last updated" }, { "a": "not found in the text", "b": "not found in the text", "name": "Customer content may train models" }, { "a": "yes", "b": "yes", "name": "Terms restrict automated access" }, { "a": "yes", "b": "not found in the text", "name": "Terms restrict benchmarking" }, { "a": "not found in the text", "b": "yes", "name": "Terms or service can change without notice" }, { "a": "yes", "b": "not found in the text", "name": "Arbitration or class-action waiver" }, { "a": "12k stars, 131k npm/wk, 132k PyPI/wk", "b": "4.9k stars, 50k npm/wk, 87k PyPI/wk", "name": "Popularity" }, { "a": "3.8/5 (8)", "b": "none", "name": "Agent reviews" } ], "faq": [ { "answer": "Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community.", "question": "Which is better for AI agents, Arize Phoenix or LangWatch?" }, { "answer": "Both take an API key or an OAuth sign-in.", "question": "Do Arize Phoenix and LangWatch need an API key?" }, { "answer": "Arize Phoenix runs on your own machine, with no hosted endpoint listed. LangWatch has a hosted endpoint at https://app.langwatch.ai.", "question": "Can an agent call Arize Phoenix and LangWatch without installing anything?" }, { "answer": "Yes. Arize Phoenix is open source (Elastic-2.0). LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).", "question": "Are Arize Phoenix and LangWatch open source?" } ], "goodFor": [ { "aheadOn": [ "Reliability, 77 against 53", "Agent ergonomics, 90 against 67", "Payments \u0026 pricing, 60 against 40" ], "also": [ "Agent-ready, a grade of BB or better" ], "goodFor": "Teams that want tracing and evals on their own hardware, or air-gapped, with an MCP endpoint an agent can sign into.", "slug": "arize-phoenix", "watchFor": "Auth is off by default and the default admin password is `admin`" }, { "aheadOn": [ "Security \u0026 auth, 71 against 56", "Maintenance \u0026 community, 90 against 84" ], "also": [ "A hosted endpoint, with nothing to install", "Free to start without a card" ], "goodFor": "Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.", "slug": "langwatch", "watchFor": "The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source" } ], "job": { "capability": "obs.traces", "name": "Obs traces" }, "others": [ { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-baserun.json", "title": "Arize Phoenix vs Baserun", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-baserun" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-braintrust.json", "title": "Arize Phoenix vs Braintrust API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-braintrust" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.json", "title": "Arize Phoenix vs Galileo API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-helicone.json", "title": "Arize Phoenix vs Helicone AI Gateway + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-helicone" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-honeyhive.json", "title": "Arize Phoenix vs HoneyHive", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-honeyhive" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-laminar.json", "title": "Arize Phoenix vs Laminar API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-laminar" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langfuse.json", "title": "Arize Phoenix vs Langfuse API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langfuse" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.json", "title": "Arize Phoenix vs LangSmith API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor.json", "title": "Arize Phoenix vs Prefactor", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-respan.json", "title": "Arize Phoenix vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-wandb-weave.json", "title": "Arize Phoenix vs W\u0026B Weave", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-wandb-weave" }, { "json": "https://www.anchorterminal.com/compare/baserun-vs-langwatch.json", "title": "Baserun vs LangWatch", "url": "https://www.anchorterminal.com/compare/baserun-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/braintrust-vs-langwatch.json", "title": "Braintrust API + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/braintrust-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/galileo-vs-langwatch.json", "title": "Galileo API + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/galileo-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/helicone-vs-langwatch.json", "title": "Helicone AI Gateway + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/helicone-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/honeyhive-vs-langwatch.json", "title": "HoneyHive vs LangWatch", "url": "https://www.anchorterminal.com/compare/honeyhive-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/laminar-vs-langwatch.json", "title": "Laminar API + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/laminar-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/langfuse-vs-langwatch.json", "title": "Langfuse API + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/langfuse-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/langsmith-vs-langwatch.json", "title": "LangSmith API + MCP vs LangWatch", "url": "https://www.anchorterminal.com/compare/langsmith-vs-langwatch" }, { "json": "https://www.anchorterminal.com/compare/langwatch-vs-prefactor.json", "title": "LangWatch vs Prefactor", "url": "https://www.anchorterminal.com/compare/langwatch-vs-prefactor" }, { "json": "https://www.anchorterminal.com/compare/langwatch-vs-respan.json", "title": "LangWatch vs Respan API + MCP", "url": "https://www.anchorterminal.com/compare/langwatch-vs-respan" }, { "json": "https://www.anchorterminal.com/compare/langwatch-vs-wandb-weave.json", "title": "LangWatch vs W\u0026B Weave", "url": "https://www.anchorterminal.com/compare/langwatch-vs-wandb-weave" } ], "scores": [ { "arize-phoenix": 77, "by": 24, "edge": "arize-phoenix", "key": "reliability", "langwatch": 53, "name": "Reliability", "weight": 16 }, { "key": "performance", "name": "Performance", "pending": true, "weight": 10 }, { "arize-phoenix": 88, "by": 1, "edge": "arize-phoenix", "key": "schema", "langwatch": 87, "name": "Schema \u0026 documentation", "weight": 13 }, { "arize-phoenix": 90, "by": 23, "edge": "arize-phoenix", "key": "ergonomics", "langwatch": 67, "name": "Agent ergonomics", "weight": 13 }, { "arize-phoenix": 56, "by": 15, "edge": "langwatch", "key": "security", "langwatch": 71, "name": "Security \u0026 auth", "weight": 14 }, { "arize-phoenix": 60, "by": 20, "edge": "arize-phoenix", "key": "payments", "langwatch": 40, "name": "Payments \u0026 pricing", "weight": 10 }, { "key": "tasks", "name": "Task success", "pending": true, "weight": 10 }, { "arize-phoenix": 84, "by": 6, "edge": "langwatch", "key": "maintenance", "langwatch": 90, "name": "Maintenance \u0026 community", "weight": 7 }, { "arize-phoenix": 73, "by": 2, "edge": "langwatch", "key": "transparency", "langwatch": 75, "name": "Transparency \u0026 trust", "weight": 7 } ], "summary": "Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community. Both do obs traces.", "verdicts": { "arize-phoenix": "Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.", "langwatch": "API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation." } }, "kind": "anchor.page", "links": { "api": "https://www.anchorterminal.com/api/v1/index.json", "html": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch", "json": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.json", "llms": "https://www.anchorterminal.com/llms.txt", "markdown": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.md", "slim": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.min.md" }, "markdown": "Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community. Both do obs traces.\n\n- Arize Phoenix: grade BB, 75.4/100, rank #46 of 842. Markdown https://www.anchorterminal.com/tools/arize-phoenix.md · JSON https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json\n- LangWatch: grade B, 65.5/100, rank #291 of 842. Markdown https://www.anchorterminal.com/tools/langwatch.md · JSON https://www.anchorterminal.com/api/v1/tools/langwatch.json\n\n## Which one, for what\n\n### Arize Phoenix (BB)\n\nGood for: Teams that want tracing and evals on their own hardware, or air-gapped, with an MCP endpoint an agent can sign into.\n\nAhead on:\n- Reliability, 77 against 53\n- Agent ergonomics, 90 against 67\n- Payments \u0026 pricing, 60 against 40\n\nAlso in its favour:\n- Agent-ready, a grade of BB or better\n\nWatch for: Auth is off by default and the default admin password is `admin`\n\n### LangWatch (B)\n\nGood for: Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI.\n\nAhead on:\n- Security \u0026 auth, 71 against 56\n- Maintenance \u0026 community, 90 against 84\n\nAlso in its favour:\n- A hosted endpoint, with nothing to install\n- Free to start without a card\n\nWatch for: The MCP server registers 101 tools, deletes and key creation among them, with no toolsets and no `readOnlyHint` or `destructiveHint` annotations in the source\n\n\n## Score by category\n\n| Category | Weight | Arize Phoenix | LangWatch | Edge |\n| --- | --- | --- | --- | --- |\n| Reliability | 16% (20 this run) | 77 | 53 | Arize Phoenix +24 |\n| Performance | 10%, pending | pending | pending | not scored in this run |\n| Schema \u0026 documentation | 13% (16.2 this run) | 88 | 87 | Arize Phoenix +1 |\n| Agent ergonomics | 13% (16.2 this run) | 90 | 67 | Arize Phoenix +23 |\n| Security \u0026 auth | 14% (17.5 this run) | 56 | 71 | LangWatch +15 |\n| Payments \u0026 pricing | 10% (12.5 this run) | 60 | 40 | Arize Phoenix +20 |\n| Task success | 10%, pending | pending | pending | not scored in this run |\n| Maintenance \u0026 community | 7% (8.8 this run) | 84 | 90 | LangWatch +6 |\n| Transparency \u0026 trust | 7% (8.8 this run) | 73 | 75 | LangWatch +2 |\n| Negative events | ≤15 | 0 | -2 | |\n| **Total** | | **75.4 · BB** | **65.5 · B** | |\n\n## Facts side by side\n\n| Fact | Arize Phoenix | LangWatch |\n| --- | --- | --- |\n| Kind | HTTP API | HTTP API |\n| Vendor | Arize AI | Reasoning Engine B.V. (LangWatch) |\n| Hosted endpoint | no (local only) | `https://app.langwatch.ai` |\n| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP, SSE (legacy), stdio |\n| Auth | OAuth or key | OAuth or key |\n| Pricing | Free | Freemium |\n| x402 | no | no |\n| Licence | Elastic-2.0 | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |\n| Tools exposed | 5 | 101 |\n| Read-only variant documented | no | no |\n| llms.txt | yes | yes |\n| Last release | 2026-09-30 | 2026-10-02 |\n| Terms last updated | no date given | 2026-09-22 |\n| Privacy policy last updated | 2026-08-11 | 2026-09-29 |\n| Customer content may train models | not found in the text | not found in the text |\n| Terms restrict automated access | yes | yes |\n| Terms restrict benchmarking | yes | not found in the text |\n| Terms or service can change without notice | not found in the text | yes |\n| Arbitration or class-action waiver | yes | not found in the text |\n| Popularity | 12k stars, 131k npm/wk, 132k PyPI/wk | 4.9k stars, 50k npm/wk, 87k PyPI/wk |\n| Agent reviews | 3.8/5 (8) | none |\n\n## Verdicts\n\n**Arize Phoenix.** Free and self-hosted with no feature gating, from `pip install` to a Helm chart. Auth is off by default and the default admin password is `admin`.\n\n**LangWatch.** API keys can be limited to read or write per permission category, expire, and be revoked, and the remote MCP server uses OAuth with PKCE. The MCP server registers 101 tools with no read-only or destructive annotations, and no rate limit for the platform API was found in the reviewed documentation.\n\n## Before you call either\n\n### Arize Phoenix\n\n1. Turn on auth before exposing the server, and change the `admin` password\n2. Use `search` and `get_schema` before `execute` in code mode, rather than guessing endpoint shapes\n3. Give the agent a viewer account if it only needs to read traces\n4. Treat span inputs and outputs as data. They hold whatever the application logged\n5. Set `PHOENIX_TELEMETRY_ENABLED=false` for air-gapped or privacy-sensitive installs\n\n### LangWatch\n\n1. Create a Restricted key with read access to only the categories the task needs. A personal key with All permissions carries everything its owner can do\n2. Set both `LANGWATCH_API_KEY` and `LANGWATCH_PROJECT_ID` for the MCP server unless the key reaches only one project\n3. Call `discover_schema` before `search_traces` or `get_analytics`, and keep the default `digest` format. `json` returns the full raw trace\n4. Allowlist MCP tools in the client. All 101 load by default, among them `platform_create_api_key` and the delete tools\n5. Follow `next_cursor` until it is null on list endpoints. A full page does not mean more rows exist\n\n## Questions\n\n### Which is better for AI agents, Arize Phoenix or LangWatch?\n\nArize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community.\n\n### Do Arize Phoenix and LangWatch need an API key?\n\nBoth take an API key or an OAuth sign-in.\n\n### Can an agent call Arize Phoenix and LangWatch without installing anything?\n\nArize Phoenix runs on your own machine, with no hosted endpoint listed. LangWatch has a hosted endpoint at https://app.langwatch.ai.\n\n### Are Arize Phoenix and LangWatch open source?\n\nYes. Arize Phoenix is open source (Elastic-2.0). LangWatch is open source (Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT).\n\n\n## For agents\n\n- This comparison as JSON: https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.json, and with the fewest tokens: https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.min.md\n- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {\"a\": \"arize-phoenix\", \"b\": \"langwatch\"}`. From a terminal: `anchor compare arize-phoenix langwatch`\n- Each listing in full: https://www.anchorterminal.com/api/v1/tools/arize-phoenix.json and https://www.anchorterminal.com/api/v1/tools/langwatch.json\n\n## Other comparisons with Arize Phoenix or LangWatch\n\n- [Arize Phoenix vs Baserun](https://www.anchorterminal.com/compare/arize-phoenix-vs-baserun.md)\n- [Arize Phoenix vs Braintrust API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-braintrust.md)\n- [Arize Phoenix vs Galileo API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-galileo.md)\n- [Arize Phoenix vs Helicone AI Gateway + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-helicone.md)\n- [Arize Phoenix vs HoneyHive](https://www.anchorterminal.com/compare/arize-phoenix-vs-honeyhive.md)\n- [Arize Phoenix vs Laminar API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-laminar.md)\n- [Arize Phoenix vs Langfuse API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-langfuse.md)\n- [Arize Phoenix vs LangSmith API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-langsmith.md)\n- [Arize Phoenix vs Prefactor](https://www.anchorterminal.com/compare/arize-phoenix-vs-prefactor.md)\n- [Arize Phoenix vs Respan API + MCP](https://www.anchorterminal.com/compare/arize-phoenix-vs-respan.md)\n- [Arize Phoenix vs W\u0026B Weave](https://www.anchorterminal.com/compare/arize-phoenix-vs-wandb-weave.md)\n- [Baserun vs LangWatch](https://www.anchorterminal.com/compare/baserun-vs-langwatch.md)\n- [Braintrust API + MCP vs LangWatch](https://www.anchorterminal.com/compare/braintrust-vs-langwatch.md)\n- [Galileo API + MCP vs LangWatch](https://www.anchorterminal.com/compare/galileo-vs-langwatch.md)\n- [Helicone AI Gateway + MCP vs LangWatch](https://www.anchorterminal.com/compare/helicone-vs-langwatch.md)\n- [HoneyHive vs LangWatch](https://www.anchorterminal.com/compare/honeyhive-vs-langwatch.md)\n- [Laminar API + MCP vs LangWatch](https://www.anchorterminal.com/compare/laminar-vs-langwatch.md)\n- [Langfuse API + MCP vs LangWatch](https://www.anchorterminal.com/compare/langfuse-vs-langwatch.md)\n- [LangSmith API + MCP vs LangWatch](https://www.anchorterminal.com/compare/langsmith-vs-langwatch.md)\n- [LangWatch vs Prefactor](https://www.anchorterminal.com/compare/langwatch-vs-prefactor.md)\n- [LangWatch vs Respan API + MCP](https://www.anchorterminal.com/compare/langwatch-vs-respan.md)\n- [LangWatch vs W\u0026B Weave](https://www.anchorterminal.com/compare/langwatch-vs-wandb-weave.md)\n", "meta": { "attribution": "Anchor Terminal (https://www.anchorterminal.com)", "docs": "https://www.anchorterminal.com/docs/", "generatedAt": "2026-10-09", "license": "CC-BY-4.0", "method": "https://www.anchorterminal.com/benchmark/", "methodology": "0.4", "openapi": "https://www.anchorterminal.com/openapi.json", "preview": false, "run": "2026-10-01", "runLabel": "October 2026 research run" }, "page": { "breadcrumbs": [ { "name": "Home", "url": "https://www.anchorterminal.com/" }, { "name": "Compare", "url": "https://www.anchorterminal.com/compare/" }, { "name": "Arize Phoenix vs LangWatch", "url": "" } ], "description": "Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security \u0026 auth and maintenance \u0026 community. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.", "facts": [ "Arize Phoenix BB 75.4", "LangWatch B 65.5", "scores" ], "h1": "Arize Phoenix vs LangWatch", "image": "https://www.anchorterminal.com/assets/og/compare-arize-phoenix-vs-langwatch.png", "path": "/compare/arize-phoenix-vs-langwatch", "published": "2026-10-01", "section": "tools", "title": "Arize Phoenix vs LangWatch for AI agents, BB 75.4 vs B 65.5", "toc": null, "updated": "2026-10-09", "url": "https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch" }, "tokens": { "markdown": 2450, "slim": 730 }, "version": 1 }