Related Keywords API
Discover semantically related keywords and variations with volume, CPC, and difficulty. Build topical authority from $0.03/call.
Discover keywords that are semantically related to your seed term. These aren't just variations — they're terms that searchers also look for, helping you build comprehensive topic coverage.
Try it live
Fill in the fields and hit Run to see a real response.
{
"ok": true,
"data": [
{
"keyword": "email automation",
"searchVolume": 8100,
"cpc": 3.2,
"difficulty": 52
},
{
"keyword": "drip campaign",
"searchVolume": 4400,
"cpc": 2.8,
"difficulty": 45
},
{
"keyword": "newsletter platform",
"searchVolume": 3600,
"cpc": 4.1,
"difficulty": 48
}
]
}Features
From a seed like "email marketing" you get adjacent terms searchers also look for — "drip campaign", "newsletter platform" — not just word reorderings, so you cover a topic the way users actually explore it.
Every related term ships with searchVolume, cpc, and a difficulty score, letting you decide which adjacent topics are worth the content investment.
The limit field (default 50) controls breadth; you are billed $0.02 + $0.02 per 100 rows, so a wide semantic map costs only as much as the rows you take.
Scope results with the location and language fields so the related set reflects regional search behavior rather than a global blend.
The semantic spread of results maps directly onto a pillar-and-cluster structure — each related term becomes a supporting page that reinforces topical authority.
Use cases
Topic Cluster Building
Map the full semantic landscape around any topic to create interlinked content that search engines reward.
Internal Linking Strategy
Discover related terms across your content to build contextual internal links that boost page authority.
Content Gap Analysis
Find related topics your site hasn't covered yet — opportunities competitors are already ranking for.
Semantic SEO
Enrich your pages with semantically related terms that signal topical authority to search engines.
FAQ Generation
Identify the questions and related searches real users have, then build FAQ sections that capture featured snippets.
Quick start
Copy this snippet and start making calls.
const res = await fetch('https://api.yepapi.com/v1/seo/keywords/related', {
method: 'POST',
headers: {
'x-api-key': 'YOUR_API_KEY',
'Content-Type': 'application/json',
},
body: JSON.stringify({
"keyword": "email marketing",
"limit": 50,
"location_code": 2840,
"language": "en"
}),
});
const data = await res.json();
console.log(data);The related keywords API for developers — map the full semantic landscape around any term
The Related Keywords API returns terms that are semantically connected to your seed — the searches users also make around a topic, not just rearranged versions of the same phrase. Each result carries search volume, CPC, and difficulty so you can build topic clusters that signal genuine authority.
Where the Keyword Ideas endpoint expands outward into volume, this endpoint maps sideways into meaning. Use both behind one YepAPI key, alongside the Keyword Gap and Content Search endpoints, to plan interlinked content hubs programmatically.
What is a related keywords API?
A related keywords API surfaces terms that are conceptually adjacent to a seed keyword — the things searchers also want when they look up a topic. For "email marketing" it returns "email automation", "drip campaign", and "newsletter platform": not spelling variants, but the neighboring intents that complete a subject. Each comes back with searchVolume, cpc, and difficulty. YepAPI exposes this at /v1/seo/keywords/related — post a seed plus an optional limit and location/language, and get a JSON array you can use to build semantically complete content rather than thin pages that target a single phrase.
Build your own related keywords tool
Use the endpoint to power a "complete this topic" feature: a writer enters a core term and your app returns the semantic neighbors they must cover to rank. Feed the results into an internal-linking engine that suggests contextual links between pages sharing related terms, or into an FAQ generator that captures the questions around a subject. Because results are scored, you can auto-prioritize which related angles to publish first and pass the rest to the On-Page Content API for depth checks.
Related keywords API pricing — $0.02 + $0.02 per 100 results
You pay $0.02 per call plus $0.02 per 100 related terms returned. The default 50-result request comes to about $0.03, and pulling several hundred related terms for a full cluster map stays well under a quarter. No seats, no monthly commitment — a stark contrast to the per-seat enterprise SEO suites that gate the same semantic data behind four-figure plans.
Build topic clusters at scale
Loop your pillar keywords through the endpoint to generate a supporting-page map for each. The semantic spread means every related term is a candidate cluster page, and the difficulty scores tell you which to write first. Combine the deduped output across pillars to spot terms that bridge multiple clusters — the high-value bridges that strengthen internal linking and topical authority across your whole site.
Try the related keywords API free
Sign up and get $5 of credit with no card required. That is enough to map dozens of pillar topics into related clusters, inspect the semantic quality, and confirm the response fits your content-planning pipeline before spending a cent.
Start making API calls in 30 seconds
$5 free credit on signup. No credit card required. Pay per call.
What developers say
“Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.”
“One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.”
“The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.”
Frequently asked questions
Discover keywords that are semantically related to your seed term. These aren't just variations — they're terms that searchers also look for, helping you build comprehensive topic coverage.
Each API call costs $0.02 (+$0.02 per 100 results). No monthly minimums or subscriptions — you only pay for what you use.
Sign up for a free API key, then send a POST request to /v1/seo/keywords/related. Check the code example above for a ready-to-use snippet in JavaScript, cURL, or Python.
YepAPI bundles SEO, AI, and web scraping APIs under one key with no monthly minimums. You get lower per-call pricing, a unified dashboard, and one billing account instead of managing multiple providers.
Ready to integrate?
Get your API key and start making calls in 30 seconds. $5 free credit on signup — no credit card required.
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