docs(metrics): add per-platform installation guides for posthog.metrics

[DanielVisca]

Changes

Adds per-platform installation guides for Metrics under /docs/metrics/installation, mirroring the logs installation docs layout:

• JavaScript (web), Node.js, and Python pages covering the posthog.metrics count/gauge/histogram API now shipped in posthog-js (#4115), posthog-node (#4117), and posthog-python (PostHog/posthog-python#739)
• Other languages page for the OTLP env-var path
• Registers the pages in the docs nav, links them from start-here, and fixes the now-stale overview note saying posthog-node support was "coming"

Why: the SDK metrics APIs shipped but only posthog-js + OTLP were documented; these pages also give the upcoming instrument-metrics agent skill (context-mill) stable per-platform doc URLs to source, matching how the logs skill works.

Checklist

• I've read the docs and/or content style guides.
• Words are spelled using American English
• Use relative URLs for internal links
• I've checked the pages added or changed in the Vercel preview build
• If I moved a page, I added a redirect in vercel.json (n/a — no pages moved)

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Created with PostHog Code

[github-actions]

Deploy preview

Status	Details	Updated (UTC)
🟢 Ready	View preview	Jul 20, 2026 08:08PM

[github-actions]

Vale prose linter → found 0 errors, 32 warnings, 0 suggestions in your markdown

Full report → Copy the linter results into an LLM to batch-fix issues.

Linter being weird? Update the rules!

contents/docs/metrics/index.mdx — 0 errors, 12 warnings, 0 suggestions

Line	Severity	Message	Rule
7:172	warning	Capitalize 'Logs' for PostHog's product. Use 'logs' for the general industry concept.	PostHogBase.ProductNames
14:4	warning	'Already have PostHog installed? Use posthog.metrics' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
14:40	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
16:5	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
16:190	warning	Use 'project token' instead of 'project API key'. The project token (phc_) is not an API key.	PostHogBase.ProjectToken
29:91	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers
53:48	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
55:4	warning	'Set up metrics with OpenTelemetry' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
65:5	warning	'2. Point your OTLP metrics exporter at PostHog' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
149:5	warning	'Already running an OpenTelemetry Collector?' heading should be in sentence case, and product names should be capitalized.	PostHogBase.SentenceCase
177:30	warning	'quantiles' is a possible misspelling.	PostHogBase.Spelling
230:6	warning	Capitalize 'Error Tracking' for PostHog's product. Use 'Error tracking' for the general industry concept.	PostHogBase.ProductNames

contents/docs/metrics/installation/_snippets/metrics-next-steps.mdx — 0 errors, 1 warnings, 0 suggestions

Line	Severity	Message	Rule
5:92	warning	Capitalize 'Logs' for PostHog's product. Use 'logs' for the general industry concept.	PostHogBase.ProductNames

contents/docs/metrics/installation/index.mdx — 0 errors, 3 warnings, 0 suggestions

Line	Severity	Message	Rule
18:89	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
19:76	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
20:75	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms

contents/docs/metrics/installation/javascript.mdx — 0 errors, 5 warnings, 0 suggestions

Line	Severity	Message	Rule
3:15	warning	Use 'JavaScript' instead of 'javascript'.	Vale.Terms
12:5	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
18:34	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
20:177	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers
55:206	warning	Capitalize 'Logs' for PostHog's product. Use 'logs' for the general industry concept.	PostHogBase.ProductNames

contents/docs/metrics/installation/nodejs.mdx — 0 errors, 4 warnings, 0 suggestions

Line	Severity	Message	Rule
3:15	warning	'nodejs' is a possible misspelling.	PostHogBase.Spelling
12:6	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
12:152	warning	Capitalize 'Feature Flags' for PostHog's product. Use 'feature flags' for the general industry concept.	PostHogBase.ProductNames
28:59	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers

contents/docs/metrics/installation/other.mdx — 0 errors, 1 warnings, 0 suggestions

Line	Severity	Message	Rule
47:64	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers

contents/docs/metrics/installation/python.mdx — 0 errors, 3 warnings, 0 suggestions

Line	Severity	Message	Rule
12:6	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
12:156	warning	Capitalize 'Feature Flags' for PostHog's product. Use 'feature flags' for the general industry concept.	PostHogBase.ProductNames
28:59	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers

contents/docs/metrics/start-here.mdx — 0 errors, 3 warnings, 0 suggestions

Line	Severity	Message	Rule
21:5	warning	Use 'PostHog' instead of 'posthog'.	Vale.Terms
55:156	warning	Avoid trivializing words. 'easy to' can sound dismissive to the reader.	PostHogDocs.Trivializers
69:87	warning	Capitalize 'Logs' for PostHog's product. Use 'logs' for the general industry concept.	PostHogBase.ProductNames

[github-actions]

Bundle report

Total JS (gzip)

6.72 MiB (+0.8 KiB / +0.0%)

Eager graph (modules shipped in each entrypoint's initial chunks)

Entrypoint	Eager size	Budget	Modules
✅ app	16.03 MiB (+5.6 KiB / +0.0%)	report-only	1966

Largest modules in the app closure

Module	Size
./src/data/mcp-tools.json	843.0 KiB
css ./node_modules/.pnpm/css-loader@5.2.7_webpack@5.101.3/node_modules/css-loader/dist/cjs.js??ruleSet[1].rules[8].oneOf[1].use[1]!./node_modules/.pnpm/postcss-loader@4.3.0_postcss@8.5.6_webpack@5.101.3/node_modules/postcss-loader/dist/cjs.js??ruleSet[1].rules[8].oneOf[1].use[2]!./src/styles/global.css	738.1 KiB
./src/components/Stickers/Stickers.tsx	696.4 KiB
./node_modules/.pnpm/@radix-ui+react-icons@1.3.2_react@18.3.1/node_modules/@radix-ui/react-icons/dist/react-icons.esm.js	481.4 KiB
./node_modules/.pnpm/rehype-raw@7.0.0/node_modules/rehype-raw/lib/index.js + 29 modules	395.1 KiB
./node_modules/.pnpm/@posthog+icons@0.36.6_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/@posthog/icons/dist/posthog-icons.cjs.js	364.8 KiB
./src/hooks/useCustomers.tsx + 54 modules	355.1 KiB
./node_modules/.pnpm/@posthog+icons@0.36.6_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/@posthog/icons/dist/posthog-icons.es.js	354.8 KiB
./node_modules/.pnpm/react-markdown@8.0.7_@types+react@16.14.66_react@18.3.1/node_modules/react-markdown/lib/react-markdown.js + 88 modules	351.4 KiB
./node_modules/.pnpm/cloudinary-core@2.14.0_lodash@4.17.21/node_modules/cloudinary-core/cloudinary-core.js	281.9 KiB
./src/components/ProductComparisonTable/index.tsx + 120 modules	278.6 KiB
./src/components/SearchUI/index.tsx + 87 modules	271.9 KiB
./node_modules/.pnpm/d3@7.9.0/node_modules/d3/src/index.js + 208 modules	247.4 KiB
./src/components/Pricing/PricingSlider/Slider.tsx + 87 modules	239.9 KiB
./gatsby-browser.tsx + 44 modules	227.0 KiB

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Eager-graph budgets are report-only until a baseline is established. Sizes are gzip of public/**/*.js; eager size is webpack module source bytes for the modules actually shipped in the entrypoint's initial chunks (post-tree-shake).