Keyword Tool API review

Our editorial read across six dimensions, scored 1 to 5. This is our own assessment, not an aggregate of user reviews, and it is deliberately kept out of the page's structured data.

• Data coverage4/5

  Sixteen platforms for suggestions and fifteen for volume. No SERP, ranking or backlink data of any kind.

• Pricing3/5

  Competitive for bulk enrichment at 1,000 keywords a call. Expensive for discovery at one seed a call.

• Documentation4/5

  Public OpenAPI 3.1 file, a Markdown copy and a full error table. The transport throttle is documented only in the spec.

• Ease of integration4/5

  One POST per call, the provider as a path slug, JSON or XML back, and a sandbox base for testing.

• Reliability3/5

  On-demand retrieval can return partial results. They are flagged and not charged, but your code must retry.

• Support3/5

  A contact route and a demo request for custom limits. No SLA published for the self-serve plans.

An editorial read, not an aggregate of user reviews, and deliberately kept out of this page's structured data.

From Keyword Tool API's own YouTube channel. Vendor marketing rather than an independent review, included because it is the quickest way to see the product before you sign up.

Keyword Tool API overview

A minimal call against the live endpoint, with credentials read from the environment rather than pasted inline.

curl -s -X POST "https://api.keywordtool.io/v2/search/volume/google?apikey=$KEYWORDTOOL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
        "keyword": ["crm software", "crm for small business", "free crm"],
        "metrics_location": [2840],
        "metrics_language": ["en"],
        "metrics_network": "googlesearch",
        "metrics_currency": "USD",
        "output": "json"
      }'

# This call costs ONE request from the daily pool whether the array
# holds 3 keywords or 1,000, so fill it. A suggestions call takes a
# single seed and costs the same one request.
#
# Check what is left before a batch:
curl -s "https://api.keywordtool.io/v2/quota?apikey=$KEYWORDTOOL_API_KEY"

# Running out of plan quota returns HTTP 404 with error code 9 (daily)
# or 7 (per minute), not 429. Branch on the code, not the status.

• Requests per rolling 24 hours: Starter 50, Growth 100, Scale 200, Agency 400, shared across web, API and MCP.
• API burst limit: 15 requests per rolling minute on all four plans.
• Transport throttle: 120 requests a minute per endpoint group per account, applied regardless of plan or response code.
• Search volume: 1 to 1,000 keywords per request, one location and one language per request.
• Keyword suggestions: one seed per request, with up to 2,000 negative keywords.
• A keyword may not exceed 80 characters or 10 words.
• Volume history: Google 12 to 48 months by plan, Bing up to 24, all other platforms 12.
• Plan quota exhaustion returns HTTP 404 (code 9 daily, code 7 per minute). HTTP 429 is reserved for the transport throttle.
• Incomplete results return code 10 with HTTP 200 and are not counted against quota.
• MCP covers Google and Bing; the web interface and REST API cover all 16 platforms.

Scores read from each source on 2026-09-13. We report them as-is and publish no rating of our own.

Capterra rates Keyword Tool as a product, which in practice means the web interface rather than the API. The newest review we could see dates from January 2025, before the current plans.

• “50 API Requests Per Day for their most expensive plan is a deal breaker, it needs to be in the thousands at least.”

  r/TechSEO on Reddit

• “You can run thousands of requests for search volume data against the keywordtool.io API. Why do you think you can only do 50 per day?”

  r/TechSEO on Reddit

• “Thanks, I understand their Google data comes through Keyword Planner and it's reliable. However, it sounds like their data for other platforms such as Amazon isn't accurate.”

  r/marketing on Reddit

• “thanks checked them out; but api is structured exclusively by locale.”

  r/TechSEO on Reddit

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