# SE Ranking, free trial, GET /v1/keywords/similar: Related keywords API

> Retrieves keywords similar to a specified seed keyword within a regional database. Semantically similar keywords include synonyms, close variations, or different phrasings with the same intent. The method returns metrics such as search volume, CPC, competition, keyword difficulty, search intent, and historical trends.

SE Ranking's related keywords API on its Free trial plan. It costs $0.00 per 1,000 keywords. It returns 5 of the 6 key fields we check: Search volume, Monthly trend, Cost per click, Competition, Keyword difficulty.
We rank 53 plans by price. [Mangools's $15 monthly plan](https://datacircle.dev/related-keywords-apis/mangools/15-monthly/llms.txt) 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.
[Mangools](https://datacircle.dev/related-keywords-apis/mangools/15-monthly/llms.txt), [DataForSEO](https://datacircle.dev/related-keywords-apis/dataforseo/top-up-from-50-pay-as-you-go-post-v3-dataforseo-labs-google-keyword-ideas-live/llms.txt) and [SE Ranking](https://datacircle.dev/related-keywords-apis/se-ranking/29-monthly-add-on-monthly-billing-get-v1-keywords-similar/llms.txt) are the best related keywords API providers in our benchmark.

- This page: https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-similar
- [Best related keywords API in 2026](https://datacircle.dev/best-related-keywords-api.txt)
- Get it: https://seranking.com/api-pricing.html
- Request: `GET https://api.seranking.com/v1/keywords/similar`
- API key: with the plan, on https://seranking.com/api-pricing.html
- Its API docs: https://seranking.com/api/data/keyword-research/#similar
- Sold by: SE Ranking (https://seranking.com)
- Checked: 2026-10-29

## In the answer

- Completeness: 83%
- Search volume: ✓
- Monthly trend: ✓
- Cost per click: ✓
- Competition: ✓
- Keyword difficulty: ✓

## Price

- $ per 1,000 keywords: $0.00
- Per: result
- Billing: free

## Charges

- Also pays for: from the same budget: Backlinks API · Domain Research API · Keyword Research API · Website Audit API · AI Search API

## Overage

- Units cap: hard

## Not found

- $ per 1,000: $0.00

## In their words

- Their pitch: Retrieves keywords similar to a specified seed keyword within a regional database. Semantically similar keywords include synonyms, close variations, or different phrasings with the same intent. The method returns metrics such as search volume, CPC, competition, keyword difficulty, search intent, and historical trends.

## Data

- Freshness: 1 month
- Keep data: no limit
- Use data: Customer may use the data obtained through the Provider API for commercial purposes, including internal analytics, client SEO audits, or reporting, provided such use complies with this Agreement and does not fall under the restricted use cases outlined below. [...] Any access to or use of the Provider API by a direct competitor of SE Ranking requires Provider’s explicit written consent. [...] The following use cases require Provider’s prior written consent: (1) Embedding raw or substantially similar API metrics inside a paid SaaS product, including white-label dashboards, API-based widgets, or multi-tenant products, (2) Reselling, sublicensing, or bulk redistribution of API data, including data-as-a-service offerings, data feeds, or mirroring Provider’s datasets or databases, (3) Use of API data to train public machine learning or language models.

## Plan

- Pay: $0
- You get: 100,000 credits
- Enough for: 10,000 results, once
- Expires: 14 days

## Rate limit

- Per second: 1
- Batch: 1

## Speed

- Median: 0.70 s

## The call

- You send: source, keyword. Optional: limit, offset, sort, sort_order, history_trend, filter[volume][from], filter[volume][to], filter[difficulty][from], filter[difficulty][to], filter[cpc][from], filter[cpc][to], filter[competition][from], filter[competition][to], filter[keyword_count][from], filter[keyword_count][to], filter[characters_count][from], filter[characters_count][to], filter[serp_features], filter[intents], filter[multi_keyword_included], filter[multi_keyword_excluded]
- Method: GET
- Path: /v1/keywords/similar

## About the plan

- Plan: Free trial
- Who can get it: anyone who confirms an email address, a direct competitor of SE Ranking excepted

## The 9 fields the plan's answer can hold

total results, keyword, search volume, cost per click, keyword difficulty, competition, search intent, SERP features, search volume trend

## SE Ranking's plans (6)

- [SE Ranking, free trial, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-similar/llms.txt): $0.00 per 1,000, 83% complete, 1 month
- [SE Ranking, top-up from $50, Wallet, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/top-up-from-50-wallet-get-v1-keywords-similar/llms.txt): $2.00 per 1,000, 83% complete, 1 month
- [SE Ranking, $29 monthly, Add-on, monthly billing, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/29-monthly-add-on-monthly-billing-get-v1-keywords-similar/llms.txt): $1.933 per 1,000, 83% complete, 1 month
- [SE Ranking, $540 yearly, Add-on, annual billing, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/540-yearly-add-on-annual-billing-get-v1-keywords-similar/llms.txt): 83% complete, 1 month
- [SE Ranking, $2,148 yearly, Standalone, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/2148-yearly-standalone-get-v1-keywords-similar/llms.txt): 83% complete, 1 month
- [SE Ranking, contact us, Enterprise, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/contact-us-enterprise-get-v1-keywords-similar/llms.txt): 83% complete, 1 month

## SE Ranking's calls for this API (3)

- `GET /v1/keywords/questions`: [SE Ranking, free trial, GET /v1/keywords/questions](https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-questions/llms.txt)
- `GET /v1/keywords/related`: [SE Ranking, free trial, GET /v1/keywords/related](https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-related/llms.txt)
- `GET /v1/keywords/similar`: [SE Ranking, free trial, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-similar/llms.txt)

## SE Ranking's APIs (5)

- [SE Ranking: keyword research API pricing, 6 plans](https://datacircle.dev/keyword-research-apis/se-ranking/free/llms.txt)
- [SE Ranking: ranked keywords API pricing, 6 plans](https://datacircle.dev/ranked-keywords-apis/se-ranking/free/llms.txt)
- [SE Ranking: backlink API pricing, 6 plans, GET /v1/backlinks/raw](https://datacircle.dev/backlink-apis/se-ranking/free-trial-get-v1-backlinks-raw/llms.txt)
- [SE Ranking: backlink API pricing, 6 plans, GET /v1/backlinks/all](https://datacircle.dev/backlink-apis/se-ranking/free-trial-get-v1-backlinks-all/llms.txt)
- [SE Ranking: domain authority API pricing, 6 plans, GET /v1/backlinks/summary](https://datacircle.dev/domain-authority-apis/se-ranking/free-trial-get-v1-backlinks-summary/llms.txt)
- [SE Ranking: domain authority API pricing, 6 plans, GET /v1/backlinks/authority/domain](https://datacircle.dev/domain-authority-apis/se-ranking/free-trial-get-v1-backlinks-authority-domain/llms.txt)
- [SE Ranking: related keywords API pricing, 6 plans, GET /v1/keywords/similar](https://datacircle.dev/related-keywords-apis/se-ranking/free-trial-get-v1-keywords-similar/llms.txt)

## SE Ranking: related keywords API alternatives

- [DataForSEO, top-up from $50, Pay as you go, POST /v3/dataforseo_labs/google/related_keywords/live](https://datacircle.dev/related-keywords-apis/dataforseo/top-up-from-50-pay-as-you-go-post-v3-dataforseo-labs-google-related-keywords-live/llms.txt): $0.12 per 1,000, 100% complete, 1 month
- [AnyAPI, top-up from $10, Manual top-up, POST /v1/run/seo.related_keywords](https://datacircle.dev/related-keywords-apis/anyapi/top-up-from-10-manual-top-up-post-v1-run-seo-related-keywords/llms.txt): $0.16 per 1,000, 100% complete, 1 month
- [SpyFu, $119 monthly, Pro + AI, GET /apis/keyword_api/v2/related/getRelatedKeywords](https://datacircle.dev/related-keywords-apis/spyfu/119-monthly-pro-ai-get-apis-keyword-api-v2-related-getrelatedkeywords/llms.txt): $2.50 per 1,000, 33% complete, 1 month

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-10-29.

- https://help.seranking.com/hc/en-us/articles/21487397355420-API-pricing
- https://seranking.com/api-pricing.html
- https://seranking.com/api/api-credits-system
- https://seranking.com/api/data/keyword-research/
- https://seranking.com/api/rate-limits
- https://seranking.com/api/usage-guidelines-for-commercial-purposes
- https://seranking.com/legal/api-terms-of-service.html