# UnifAPI, top-up, Pay-as-you-go, POST /seo/keywords/suggestions: Related keywords API

> Expand a seed keyword into long-tail search queries that include it, each with search volume, CPC, competition, keyword difficulty, and search intent for SEO and content research.

UnifAPI's related keywords API on its Pay-as-you-go plan. It costs $1.00 per 1,000 keywords. It returns all 6 key fields we check: Search volume, Monthly trend, Cost per click, Competition, Keyword difficulty, Search intent.
Half of the 72 plans we rank by price cost $0.80 per 1,000 keywords or less. This plan is cheaper than 25% of the 72 plans.
[Mangools's $15 monthly plan](https://datacircle.dev/related-keywords-apis/mangools/15-monthly/llms.txt) is the cheapest paid plan 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/unifapi/top-up-pay-as-you-go-post-seo-keywords-suggestions
- [Best related keywords API in 2026: pricing compared](https://datacircle.dev/best-related-keywords-api.txt)
- Get it: https://unifapi.com/pricing
- Request: `POST https://api.unifapi.com/seo/keywords/suggestions`
- API key: with the plan, on https://unifapi.com/pricing
- Its API docs: https://docs.unifapi.com/api/seo/keywords/suggestions/post
- Sold by: UnifAPI (https://unifapi.com)
- Checked: 2026-11-01

## In the answer

- Completeness: 100%
- Search volume: ✓
- Monthly trend: ✓
- Cost per click: ✓
- Competition: ✓
- Keyword difficulty: ✓
- Search intent: ✓

## Price

- $ per 1,000 keywords: $1.00
- Per: result
- Billing: pay first

## Charges

- Also pays for: from the same budget: 324 other calls

## Not found

- $ per 1,000: $50.00

## In their words

- Their pitch: Expand a seed keyword into long-tail search queries that include it, each with search volume, CPC, competition, keyword difficulty, and search intent for SEO and content research.

## Data

- Keep data: no limit
- Use data: You agree not to use our services for any unlawful purpose or in any way that could damage, disable, or impair the service. Prohibited activities include but are not limited to: Violating any applicable laws or regulations, Infringing on intellectual property rights, Transmitting malicious code or harmful content, Attempting to gain unauthorized access to systems, Interfering with or disrupting the service. [...] You may not use our services to: [...] Send unsolicited bulk messages (spam) [...] Circumvent any access controls or usage limits [...]. Public data has different legal postures depending on jurisdiction and platform. We provide the technical access, you're responsible for downstream use.

## Plan

- Expires: never

## Rate limit

- Per second: 1
- Batch: 1

## The call

- You send: keyword. Optional: location, language, limit, offset, offset_token, exact_match, ignore_synonyms, include_serp_info, include_seed_keyword, view
- Method: POST
- Path: /seo/keywords/suggestions

## About the plan

- Plan: Pay-as-you-go
- Who can get it: anyone

## The 24 fields the plan's answer can hold

seed keyword, location, language, view, total results, offset, offset token, keyword, search volume, CPC, competition, competition level, keyword difficulty, search intent, alternative search intents, low top of page bid, high top of page bid, words count, detected language, search volume trend, SERP item types, SERP results count, monthly searches, last updated at

## UnifAPI's plans (3)

- [UnifAPI, top-up, Pay-as-you-go, POST /seo/keywords/suggestions](https://datacircle.dev/related-keywords-apis/unifapi/top-up-pay-as-you-go-post-seo-keywords-suggestions/llms.txt): $1.00 per 1,000, 100% complete
- [UnifAPI, top-up, Starter top-up, POST /seo/keywords/suggestions](https://datacircle.dev/related-keywords-apis/unifapi/top-up-starter-top-up-post-seo-keywords-suggestions/llms.txt): $1.00 per 1,000, 100% complete
- [UnifAPI, contact us, Enterprise, POST /seo/keywords/suggestions](https://datacircle.dev/related-keywords-apis/unifapi/contact-us-enterprise-post-seo-keywords-suggestions/llms.txt): 100% complete

## UnifAPI's calls for this API (3)

- `POST /seo/keywords/ideas`: [UnifAPI, top-up, Pay-as-you-go, POST /seo/keywords/ideas](https://datacircle.dev/related-keywords-apis/unifapi/top-up-pay-as-you-go-post-seo-keywords-ideas/llms.txt)
- `POST /seo/keywords/suggestions`: [UnifAPI, top-up, Pay-as-you-go, POST /seo/keywords/suggestions](https://datacircle.dev/related-keywords-apis/unifapi/top-up-pay-as-you-go-post-seo-keywords-suggestions/llms.txt)
- `POST /seo/keywords/related`: [UnifAPI, top-up, Pay-as-you-go, POST /seo/keywords/related](https://datacircle.dev/related-keywords-apis/unifapi/top-up-pay-as-you-go-post-seo-keywords-related/llms.txt)

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## UnifAPI: related keywords API alternatives

- [Ahrefs, $129 monthly, Lite, GET /v3/keywords-explorer/related-terms, Related terms](https://datacircle.dev/related-keywords-apis/ahrefs/129-monthly-lite-get-v3-keywords-explorer-related-terms-related-terms/llms.txt): $0.645 per 1,000, 50% complete
- [Keywords Everywhere, $168 yearly, Silver, POST /v1/get_related_keywords](https://datacircle.dev/related-keywords-apis/keywords-everywhere/168-yearly-silver-post-v1-get-related-keywords/llms.txt): $0.84 per 1,000, 0% complete
- [SpyFu, $119 monthly, Pro + AI, GET /apis/keyword_api/v2/related/getAlsoBuysAdsForKeywords](https://datacircle.dev/related-keywords-apis/spyfu/119-monthly-pro-ai-get-apis-keyword-api-v2-related-getalsobuysadsforkeywords/llms.txt): $1.00 per 1,000, 67% complete, 1 month
- [Moz, $500 monthly](https://datacircle.dev/related-keywords-apis/moz/500-monthly/llms.txt): $1.00 per 1,000, 0% complete

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-11-01.

- https://api.unifapi.com/openapi.json
- https://docs.unifapi.com/api/seo/keywords/suggestions/post
- https://docs.unifapi.com/rate-limits
- https://unifapi.com/apis/linkedin
- https://unifapi.com/apis/seo/keywords/suggestions/post
- https://unifapi.com/legal/acceptable-use-policy
- https://unifapi.com/legal/terms-of-service
- https://unifapi.com/pricing
- https://unifapi.com/pricing.md