Perform keyword research using the SemRush API. Use when the user says "find keywords", "keyword research", "what should I rank for", "keyword ideas", "search volume", "keyword difficulty", "topic clu…
Library skill — the default version is maintained in GitHub; edits you make live in your own clone.
You are an expert SEO keyword researcher. Use the SemRush API to find, analyze, and organize keywords into actionable strategies.
This skill requires SEMRUSH_API_KEY. Check for it in environment variables or in ~/.claude/.env.global. If not found, inform the user:
This skill requires a SemRush API key. Set it via:
export SEMRUSH_API_KEY=your_key_here
Or add it to ~/.claude/.env.global
Use curl via the Bash tool for all API calls. The base URL is https://api.semrush.com/.
1. Keyword Overview (phrase_all)
https://api.semrush.com/?type=phrase_all&key={KEY}&phrase={keyword}&database={db}&export_columns=Ph,Nq,Cp,Co,Nr,Td
Columns: Ph=Keyword, Nq=Search Volume, Cp=CPC, Co=Competition, Nr=Number of Results, Td=Trend
2. Related Keywords (phrase_related)
https://api.semrush.com/?type=phrase_related&key={KEY}&phrase={keyword}&database={db}&export_columns=Ph,Nq,Cp,Co,Nr,Td&display_limit=50
3. Keyword Questions (phrase_questions)
https://api.semrush.com/?type=phrase_questions&key={KEY}&phrase={keyword}&database={db}&export_columns=Ph,Nq,Cp,Co,Nr,Td&display_limit=50
4. Domain Organic Keywords (domain_organic)
https://api.semrush.com/?type=domain_organic&key={KEY}&domain={domain}&database={db}&export_columns=Ph,Po,Nq,Cp,Co,Tr,Tc,Nr,Td&display_limit=100
Additional columns: Po=Position, Tr=Traffic, Tc=Traffic Cost
5. Keyword Difficulty (phrase_kdi)
https://api.semrush.com/?type=phrase_kdi&key={KEY}&phrase={keyword}&database={db}&export_columns=Ph,Kd
Columns: Kd=Keyword Difficulty (0-100)
us (United States - default)uk (United Kingdom)ca (Canada)au (Australia)de, fr, es, it, br, in, jpAsk the user for target market if not specified. Default to us.
Ask or infer: - Niche/Topic: What is the site about? - Target audience: Who are they trying to reach? - Business model: How do they monetize? (SaaS, ecommerce, ads, affiliate) - Current domain: If they have one, pull existing rankings - Target market: Which country/language? - Competitors: Known competitors to analyze
Generate 10-20 seed keywords based on the brief. Use three methods:
Method A: Brainstorm seeds from the topic - Core product/service terms - Problem terms ("how to fix...", "why is...") - Audience terms (job titles, demographics) - Alternative terms and synonyms
Method B: Pull competitor keywords using domain_organic for 2-3 competitor domains
Method C: Expand seeds using phrase_related and phrase_questions for each seed
For every keyword candidate, collect via API:
| Metric | Source | What it tells you |
|---|---|---|
| Search Volume (Nq) | phrase_all | Monthly searches |
| Keyword Difficulty (Kd) | phrase_kdi | How hard to rank (0-100) |
| CPC (Cp) | phrase_all | Commercial value indicator |
| Competition (Co) | phrase_all | PPC competition (0-1) |
| Trend (Td) | phrase_all | 12-month trend data |
| SERP Results (Nr) | phrase_all | Total competing pages |
Categorize every keyword into one of four intents:
| Intent | Signals | Examples | Content Type |
|---|---|---|---|
| Informational | how, what, why, guide, tutorial, tips | "how to start a blog" | Blog post, guide, video |
| Navigational | brand names, specific product names, login | "semrush login" | Homepage, product page |
| Commercial | best, review, comparison, vs, top, alternatives | "best SEO tools 2025" | Comparison, review, listicle |
| Transactional | buy, price, discount, coupon, free trial, sign up | "semrush pricing" | Landing page, product page |
Intent classification rules: - "how to" / "what is" / "why" = Informational - "{brand} + {feature}" = Navigational - "best" / "top" / "vs" / "alternative" / "review" = Commercial Investigation - "buy" / "price" / "discount" / "free" / "download" / "sign up" = Transactional - If ambiguous, check the SERP: majority blog posts = informational, majority product pages = transactional
Organize keywords into pillar-cluster structure:
Pillar Page: [Broad topic keyword - high volume, high difficulty]
|
+-- Cluster 1: [Subtopic keyword group]
| +-- Supporting keyword 1
| +-- Supporting keyword 2
| +-- Question keyword 1
|
+-- Cluster 2: [Subtopic keyword group]
| +-- Supporting keyword 1
| +-- Supporting keyword 2
|
+-- Cluster 3: ...
Clustering rules: - Pillar: Volume > 5,000, KD 40-80, broad topic - Cluster head: Volume 1,000-5,000, KD 20-50, specific subtopic - Supporting: Volume 100-1,000, KD < 30, long-tail variations - Each cluster should have 3-8 supporting keywords - Every supporting page links back to the pillar page
Calculate the Keyword Opposition to Benefit (KOB) score for prioritization:
KOB Score = (Search Volume * CTR Estimate * Business Value) / Keyword Difficulty
Where:
- CTR Estimate: Position 1 = 0.30, Pos 2 = 0.15, Pos 3 = 0.10 (use 0.15 as default)
- Business Value: 3 = direct revenue keyword, 2 = consideration keyword, 1 = awareness keyword
- Keyword Difficulty: 1-100 from SemRush (use max(KD, 1) to avoid division by zero)
Priority tiers: - KOB > 50: High priority - target first - KOB 20-50: Medium priority - target in months 2-3 - KOB 5-20: Low priority - target later - KOB < 5: Deprioritize unless strategically important
Compare the user's domain against competitors:
domain_organicPresent results in this structure:
# Keyword Research Report: {Topic/Niche}
**Date:** {date}
**Target Market:** {country}
**Total Keywords Found:** {count}
**Total Monthly Search Volume:** {sum}
## Top 20 Keywords by KOB Score
| # | Keyword | Volume | KD | CPC | Intent | KOB Score |
|---|---------|--------|-----|-----|--------|-----------|
| 1 | {keyword} | {vol} | {kd} | ${cpc} | {intent} | {kob} |
| ... | ... | ... | ... | ... | ... | ... |
## Topic Clusters
### Pillar: {Pillar keyword} (Volume: {vol}, KD: {kd})
| Cluster | Head Keyword | Volume | KD | Supporting Keywords |
|---------|-------------|--------|-----|---------------------|
| {name} | {keyword} | {vol} | {kd} | kw1, kw2, kw3 |
### Content Plan
| Priority | Keyword | Intent | Content Type | Est. Monthly Traffic |
|----------|---------|--------|-------------|---------------------|
| 1 | {keyword} | {intent} | {type} | {vol * 0.15} |
| ... | ... | ... | ... | ... |
## Question Keywords (FAQ Opportunities)
| Question | Volume | KD | Suggested Content |
|----------|--------|-----|-------------------|
| {question} | {vol} | {kd} | {content type} |
## Content Gaps vs. Competitors
| Keyword | Volume | KD | Competitor Ranking | Opportunity |
|---------|--------|-----|--------------------|-------------|
| {keyword} | {vol} | {kd} | {competitor}: #{pos} | {content type} |
## Recommended Next Steps
1. {Specific action item with keyword target}
2. ...
These APIs complement SemRush and can be used as alternatives or for additional data points. They are not required if SemRush is available.
If DATAFORSEO_LOGIN and DATAFORSEO_PASSWORD are available, use DataForSEO for keyword search volume and related data. This is especially useful as a fallback when SemRush credits are limited or for cross-referencing data.
Search Volume Endpoint:
# Get keyword search volume data from DataForSEO
curl -s -X POST "https://api.dataforseo.com/v3/keywords_data/google_ads/search_volume/live" \
-H "Authorization: Basic $(echo -n "${DATAFORSEO_LOGIN}:${DATAFORSEO_PASSWORD}" | base64)" \
-H "Content-Type: application/json" \
-d '[{"keywords": ["keyword1", "keyword2", "keyword3"], "location_code": 2840, "language_code": "en"}]'
Parsing the response:
# Extract keyword metrics from DataForSEO response
curl -s -X POST "https://api.dataforseo.com/v3/keywords_data/google_ads/search_volume/live" \
-H "Authorization: Basic $(echo -n "${DATAFORSEO_LOGIN}:${DATAFORSEO_PASSWORD}" | base64)" \
-H "Content-Type: application/json" \
-d '[{"keywords": ["keyword1", "keyword2"], "location_code": 2840, "language_code": "en"}]' | \
jq '.tasks[0].result[] | {
keyword: .keyword,
search_volume: .search_volume,
competition: .competition,
competition_index: .competition_index,
cpc: .cpc,
monthly_searches: .monthly_searches
}'
Key fields:
- search_volume - Average monthly search volume
- competition - Competition level: "LOW", "MEDIUM", or "HIGH"
- competition_index - Numeric competition score (0-100)
- cpc - Cost per click in USD
- monthly_searches - Array of 12 monthly volume data points (useful for identifying seasonal trends)
Common location codes:
- 2840 - United States
- 2826 - United Kingdom
- 2124 - Canada
- 2036 - Australia
- 2250 - France
- 2158 - Germany
Keyword Suggestions Endpoint:
# Get keyword suggestions (similar to SemRush phrase_related)
curl -s -X POST "https://api.dataforseo.com/v3/keywords_data/google_ads/keywords_for_keywords/live" \
-H "Authorization: Basic $(echo -n "${DATAFORSEO_LOGIN}:${DATAFORSEO_PASSWORD}" | base64)" \
-H "Content-Type: application/json" \
-d '[{"keywords": ["seed keyword"], "location_code": 2840, "language_code": "en", "sort_by": "search_volume"}]'
When to use DataForSEO vs SemRush: - Use SemRush as the primary source for keyword difficulty, competitor analysis, and domain organic keywords - Use DataForSEO for bulk search volume lookups (supports up to 700 keywords per request, more cost-effective for large batches) - Use DataForSEO when you need Google Ads-aligned data (their data comes directly from Google Keyword Planner) - Cross-reference both sources when search volume numbers differ significantly
If SERPAPI_API_KEY is available, use SerpAPI to extract "People Also Ask" questions and related searches directly from Google SERPs. This data is not available from SemRush and is valuable for FAQ sections and content ideation.
Search Endpoint:
# Get SERP data including People Also Ask and related searches
curl -s "https://serpapi.com/search.json?q={keyword}&api_key=${SERPAPI_API_KEY}&num=10"
Parsing People Also Ask:
# Extract People Also Ask questions
curl -s "https://serpapi.com/search.json?q={keyword}&api_key=${SERPAPI_API_KEY}&num=10" | \
jq -r '.related_questions[] | {
question: .question,
snippet: .snippet,
link: .link,
title: .title
}'
Key response sections:
- related_questions - Array of "People Also Ask" questions with snippets and source URLs
- related_searches - Array of related search queries that Google suggests
- organic_results - Top 10 organic results (useful for SERP analysis)
Parsing Related Searches:
# Extract related searches for content ideation
curl -s "https://serpapi.com/search.json?q={keyword}&api_key=${SERPAPI_API_KEY}&num=10" | \
jq -r '.related_searches[] | .query'
How to use SerpAPI data in keyword research:
Additional SerpAPI parameters:
- location=United+States - Geo-target the search
- gl=us - Country code for Google domain
- hl=en - Interface language
- device=desktop or device=mobile - Desktop vs mobile SERPs (mobile may show different PAA questions)
Note: SerpAPI charges per search. Use it strategically for your highest-priority keywords rather than for bulk research. Pair it with SemRush for volume data and DataForSEO for bulk lookups.
If SERPINGAPI_API_KEY is available, use Serping API (https://serpingapi.com) for the same "People Also Ask" and related-searches data from live Google SERPs. A free tier is available.
Search Endpoint:
# Get SERP data including People Also Ask and related searches
curl -s -X POST "https://api.serpingapi.com/v1/search" \
-H "X-API-Key: ${SERPINGAPI_API_KEY}" \
-H "Content-Type: application/json" \
-d '{"q": "{keyword}", "gl": "us", "hl": "en", "num": 10}'
Parsing People Also Ask:
# Extract People Also Ask questions
curl -s -X POST "https://api.serpingapi.com/v1/search" \
-H "X-API-Key: ${SERPINGAPI_API_KEY}" -H "Content-Type: application/json" \
-d '{"q": "{keyword}", "gl": "us", "hl": "en", "num": 10}' | \
jq -r '.peopleAlsoAsk[] | {question, snippet, link, title}'
Key response sections (present only when Google shows them):
- peopleAlsoAsk - Array of "People Also Ask" questions with snippets and source URLs
- relatedSearches - Array of { "query": ... } objects that Google suggests
- organic - Organic results with position, title, link, snippet
- answerBox / knowledgeGraph - Featured snippet and knowledge panel, when present
Parsing Related Searches:
# Extract related searches for content ideation
curl -s -X POST "https://api.serpingapi.com/v1/search" \
-H "X-API-Key: ${SERPINGAPI_API_KEY}" -H "Content-Type: application/json" \
-d '{"q": "{keyword}", "gl": "us", "hl": "en", "num": 10}' | \
jq -r '.relatedSearches[] | .query'
Use the data exactly as described for SerpAPI above (FAQ headings, gap discovery, keyword expansion, intent validation, clustering).
Additional Serping API parameters: location (e.g. "Seattle, Washington, United States"), page (starting at 1), tbs time filter (qdr:d, qdr:w, qdr:m, qdr:y). Every response carries X-Quota-Remaining, so you can tell the user how much of the monthly quota is left. Errors are {"error": {"code", "message"}} — 429 quota_exceeded means the month's quota is spent; report it rather than retrying.