Datacircle

Best related keywords API in 2026

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Mangools, DataForSEO and SE Ranking are the best related keywords API providers in our benchmark. We benchmarked 3 providers. We list all three, ranked by score. For each one, we show its top scoring plan, each part of the plan's score and what 1,000 keywords cost. We rank 53 plans by price. Mangools's $15 monthly plan costs the least per 1,000 keywords: $0.0001. Mangools charges for each page of results. We count 10,000 keywords on each page to get the $0.0001 price.

  1. #1 Mangools: Related keywords API

    Mangools, $15 monthly

    It returns 5 of the 6 key fields we check: Search volume, Monthly trend, Cost per click, Competition, Keyword difficulty.

    Overall score
    92.5
    $ per 1,000
    $0.0001
    Price score
    88
    • $ per 1,000 keywords the provider has no data for: the provider's pages don't say
    • Plans of this API we rank by price: 53
    • Plans cheaper per 1,000 keywords than this plan: 0
    Data score
    100
    Cost to get started score
    87
    • How you pay: monthly
    • Least to pay before your first result: $15
    Bundle score
    88
    • Also pays for: Get keyword details · Get SERP results w. all metrics + snapshot and 1 more
    • Also pays for, from the same budget: Get details for a set of keywords · Get list of keywords for domain or URL and 2 more
    Performance score
    N/A
    • On 29 October 2026, we sent this provider the same 20 seeds as every other provider in our benchmark.
    • This plan scored 1 out of 1 on those 20 seeds. That gives this plan a Data score of 100 out of 100.

  2. #2 DataForSEO: Related keywords API

    DataForSEO, top-up from $50, Pay as you go

    It returns all 6 key fields we check: Search volume, Monthly trend, Cost per click, Competition, Keyword difficulty, Search intent.

    Overall score
    70.9
    $ per 1,000
    $0.12
    Price score
    63
    • $ per 1,000 keywords the provider has no data for: the provider's pages don't say
    • Plans of this API we rank by price: 53
    • Plans cheaper per 1,000 keywords than this plan: 15
    Data score
    88
    Cost to get started score
    82
    • How you pay: a top-up you pay first
    • Least to pay before your first result: $50
    Bundle score
    92
    • Also pays for, from the same budget: SERP API · AI Optimization API · Backlinks API · Content Analysis API · DataForSEO Labs API and 7 more
    Performance score
    4
    • This call's median time on 29 October 2026, minus the baseline: 2.626 s
    • DataForSEO, Related Keywords, the fastest provider we benchmarked that answers from a copy: under 0.1 s, counted as 0.1 s
    • On 29 October 2026, we sent this provider the same 20 seeds as every other provider in our benchmark.
    • This plan scored 0.8784 out of 1 on those 20 seeds. That gives this plan a Data score of 88 out of 100.

  3. #3 SE Ranking: Related keywords API

    SE Ranking, $29 monthly, Add-on, monthly billing

    It returns 5 of the 6 key fields we check: Search volume, Monthly trend, Cost per click, Competition, Keyword difficulty.

    Overall score
    36.1
    $ per 1,000
    $1.93
    Price score
    32
    • $ per 1,000 keywords the provider has no data for: $0
    • Plans of this API we rank by price: 53
    • Plans cheaper per 1,000 keywords than this plan: 41
    Data score
    21
    Cost to get started score
    82
    • How you pay: monthly
    • Least to pay before your first result: $29
    Bundle score
    86
    • Also pays for: Project Management API
    • Also pays for, from the same budget: Backlinks API · Domain Research API · Keyword Research API · Website Audit API · AI Search API
    Performance score
    14
    • This call's median time on 29 October 2026, minus the baseline: 0.699 s
    • DataForSEO, Related Keywords, the fastest provider we benchmarked that answers from a copy: under 0.1 s, counted as 0.1 s
    • On 29 October 2026, we sent this provider the same 20 seeds as every other provider in our benchmark.
    • This plan scored 0.2142 out of 1 on those 20 seeds. That gives this plan a Data score of 21 out of 100.

The Data score on related keywords APIs

This score, out of 100, tells you how many keywords related to a seed keyword a provider's call returns. We ask for the keywords related to each seed keyword, in the United States and in English. For each seed, we count up to 100 of the keywords the provider's call returned. We count them out of 100. If every call sent fewer than 100 keywords, we count out of the largest number sent. We check how many keywords have each field, such as the search volume and the cost per click. We score each field against the highest count any provider got on that seed. A live call is scored only against live calls. We average the scores over all seeds. Each seed counts the same. A seed with no keyword in the answer counts as 0. We compare a provider that ran on fewer seeds with the other providers on those same seeds. A provider can't score higher by running only on easy seeds. We lower the score when we test the call on fewer seeds than the benchmark has.

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