The 7 Best Keyword Research APIs in 2026 (Priced and Compared)

The same keyword data varies 14x in price.

Same source. Same numbers. Fourteen times the bill. Google Ads search volume costs about $0.00006 per keyword through one API on this list and $0.00084 through another, and nothing about the two product pages makes that obvious. You find out after you’ve built against one.

TL;DR: The best keyword research API is Answer Socrates, because one request returns the entire hundreds of keywords rather than one keyword, so you pay per pull instead of per term.

If you need raw search volume on millions of terms, or you want real query data for a site you already own, the pick changes, and both are covered below.

We priced every API on the same basis: what one keyword actually costs, what the request limits are, and whether you can test before committing.

Quick Overview

1. Answer Socrates API: Best for Question and Cluster Data

The Answer Socrates API is the best keyword research API for question data because one request returns the whole set, not one keyword.

That’s the thing to understand before comparing prices. Most APIs on this list bill per keyword or per row. Answer Socrates bills per call, and a call returns everything Google Suggest holds for that seed, grouped and ready to use.

You can use it three ways:

• Google autocomplete keyword research
• Google trends data
• Cluster keywords and get search intent

For Google trends you can find break out topics and compare different GEOs to uncover multiple new topics that are really searched.

A live pull on the seed “ai keyword research” returned 174 keywords in one request: 45 Questions, 34 Comparisons, 30 Prepositions and 65 Autocomplete expansions. Broader seeds commonly return 500 to 900. That’s one request either way.

So the per-keyword maths inverts. Seneca at $39 a month includes 6,000 API credits a year, which looks small next to competitors quoting millions. At roughly 500 keywords a call/credit, those 6,000 requests are around 3 million keywords of grouped question data a year, and the grouping is work you’d otherwise do yourself.

Then this is an example of clustering on a small keyword group, which uses the cluster credits on the account.

The endpoints are the useful ones rather than the exhaustive ones: the full keyword pull, Google Trends interest over time, rising topics with breakouts, keyword clustering, search intent, funneling, and project saves. Usage checks and project calls are free, so monitoring your own consumption never costs anything.

The MCP server runs on the same credits, which matters if you’re pointing an AI agent at this. An agent making calls behaves nothing like a person clicking, and flat per-request pricing is far easier to cap than per-row billing.

Pros

• One request returns the full grouped set
• Free usage checks and project calls
• MCP server included on the same plan
• Questions, Comparisons and Prepositions pre-sorted
• Keyword clustering

Cons

• Google Suggest and Trends, no Bing or Amazon data
• No backlink or domain authority endpoints
• API needs the $39 plan, not the $19 one

Pricing

API access starts on Seneca at $39/month with 6,000 API credits a year. Aurelius is $69/month with 30,000, and Senate, the team plan, is $299/month with 300,000. Yearly billing saves 17%, with a 7-day money-back guarantee. The free plan has no API, but it does include 3 searches a day and 500 cluster credits a month in the app, which is enough to see what the data looks like before you build. Docs at answersocrates.com/docs/api.

Best for anyone building question-based content tooling, clustering, or an AI agent that needs grouped keyword data. Skip it if you need search volume on millions of individual terms.

Try Answer Socrates free

2. DataForSEO: Best for Raw Volume at Scale

DataForSEO is the cheapest way to get Google Ads search volume in bulk, and it isn’t close.

The Google Ads endpoint costs $0.06 per task in the standard queue, with up to 1,000 keywords per task. That works out at roughly $60 per million keywords. Live mode, which skips the queue, is $0.09 per task. Bing Ads data is priced the same per task but caps at 200 keywords, so it lands nearer $300 per million.

Google Trends through their API is $0.0027 per task in standard queue at five keywords a task, or $0.011 live. Their own DataForSEO Trends product goes cheaper still at $0.0012 a task.

The model is pay as you go with no subscription, which is the right fit for irregular work. The catch is a $50 minimum payment, so it isn’t a tool you try for a fiver.

Breadth is the other reason people land here. Beyond keyword data there’s a SERP API, Labs, backlinks, on-page, Amazon and Google Shopping merchant endpoints, business listings and app store data. If you’re building a product rather than running a workflow, this is usually the layer underneath it. They ship an MCP server too.

Treat the documentation as part of the product. The endpoint naming takes a day to get used to, and the difference between standard queue and live mode is a 50% price swing you want to make deliberately.

Pros

• Around $60 per million keywords of volume
• No subscription, pay only for calls
• SERP, backlinks, Amazon and app endpoints too

Cons

• $50 minimum payment to start
• No free tier to test against
• Endpoint structure takes time to learn

Pricing

Pay as you go, $50 minimum payment. Google Ads keyword data $0.06 per task standard or $0.09 live, up to 1,000 keywords per task. Bing Ads $0.06 and $0.09 at 200 keywords per task. Google Trends $0.0027 standard, $0.011 live. Custom quotes for high volume.

Best for developers building a product on top of search data. Skip it if you want a dashboard or a free trial.

3. Google Search Console API: Best Free API for Keywords You Already Rank For

The Search Console API is free, and it’s the only one here that knows something about your site that no paid tool does.

Every other API on this list tells you what the world searches. This one tells you what the world searches and finds you for. Query, impressions, clicks, click-through rate and average position, straight from Google, for your own verified properties.

That difference decides what it’s good at. For discovering new keywords it’s useless, because it only reports terms you already appear for. For deciding what to do next it’s the strongest data you can get, because a query sitting at position 11 with 4,000 impressions and no clicks is a page you can fix this afternoon. No volume estimate comes close to that as a signal.

The Search Analytics endpoint takes the dimensions you’d want: query, page, country, device, date, hour and search appearance. You can combine them, so “which queries on mobile in Germany lost position last month” is one call.

Two limits to design around. Row limit is 1 to 25,000 per request, defaulting to 1,000, so anything large needs pagination. And Google states plainly that the API “does not guarantee to return all data rows but rather top ones”, so treat it as the top of the distribution rather than a complete export. Data goes back 16 months, which is the Search Console retention window rather than an API choice.

Setup is OAuth against a property you’ve verified. More work than pasting a token, and free forever once it’s done.

Pros

• Free, with no credit limit or quota purchase
• Real query data, not estimated volume
• Query, page, country, device and date dimensions

Cons

• Only sites you own and have verified
• Returns top rows, not guaranteed-complete data
• No keyword discovery beyond what you rank for

Pricing

Free. You need a verified Search Console property and OAuth credentials. Row limit 1 to 25,000 per request, default 1,000. Sixteen months of history.

Best for anyone optimising a site that already gets impressions. Skip it if you’re researching a topic you haven’t published on yet.

4. Google Ads API, Best Free Source of Search Volume

The Google Ads API is free, it’s the original source most of this list resells, and almost nobody building a side project uses it. Worth knowing why before you pay for anything.

Pair it with Search Console above and the two free options cover the whole picture between them. Search Console tells you about keywords you already rank for. Google Ads tells you about every other keyword.

It’s free with a Google Ads account, and the Keyword Planner data behind it is where a large share of commercial search volume ultimately comes from. If budget is the constraint, start here.

Two things bite. First, Keyword Planner returns volume as ranges rather than exact figures unless you’re running active ad spend. “1K to 10K per month” is a wide band to make content decisions on, and it’s the reason paid tools exist at all. Second, getting API access means a developer token and an approval process, which is a slower start than pasting a token into a config file.

There’s no question grouping, no clustering and no SERP data. It’s volume, competition and bid estimates, which is exactly what it was built for: buying ads.

Pros

• Free with a Google Ads account
• The original source behind most paid tools
• Bid and competition data included

Cons

• Volume as ranges without active ad spend
• Developer token and approval needed
• No question, cluster or SERP data

Pricing

Free. You need a Google Ads account and an approved developer token. Exact volume figures rather than ranges generally require active spend.

Best for developers with time and no budget. Skip it if you need precise volume or want to start this afternoon.

5. Keywords Everywhere API: Best Cheap Per-Keyword Lookups

Keywords Everywhere is the budget option for plain volume lookups, and the pricing is refreshingly legible: one credit gets you one keyword.

What arrives for that credit is more than most: search volume, CPC, competition and a 12-month trend line, all in one response. No separate call for history.

Bronze is $84 a year for 100,000 credits, which is about $0.00084 a keyword. Silver is $168 for 400,000, Gold is $480 for 2 million, and Platinum is $1,440 for 8 million. The per-keyword rate improves considerably at the top: Platinum works out near $0.00018.

Run that against DataForSEO and the gap is the whole point of this article. At entry level you’re paying roughly fourteen times more per keyword here than through DataForSEO’s Google Ads endpoint. At Platinum it narrows to about three times. You’re paying for simplicity, and for a lot of people that’s a fair trade.

Everything is annual billing. There’s no monthly option, which is worth knowing before you commit a year to an integration you haven’t built yet.

Pros

• One credit, one keyword, no maths
• Volume, CPC, competition and trend in one call
• $84 a year is the cheapest real entry point

Cons

• Annual billing only, no monthly
• Up to 14x DataForSEO’s per-keyword rate
• No question or clustering endpoints

Pricing

Bronze $84/year for 100,000 credits. Silver $168/year for 400,000. Gold $480/year for 2 million. Platinum $1,440/year for 8 million. One credit returns volume, CPC, competition and 12-month trend for one keyword. All plans annual.

Best for small tools and scripts that need volume and nothing clever. Skip it if you need question data or monthly billing.

6. Keyword Tool API: Best for Multi-Platform Autocomplete

Keyword Tool covers more platforms than anything else here, which makes it the pick when Google isn’t the surface you care about.

It pulls autocomplete from 16 platforms: Google, YouTube, Bing, Amazon, eBay, App Store, Play Store, Instagram, X, Reddit, Pinterest, Etsy, TikTok, Naver, Perplexity and Google Trends. If you sell on Etsy or publish on YouTube, that single list is the reason to look.

API and MCP access come with every paid plan, which is unusually clean. No separate API product and no add-on.

Now read the limit, because it’s the catch and it’s easy to miss. Plans are metered in requests per day, not per keyword: 50 a day on Starter at $68 a month, 100 on Growth at $148, 200 on Scale at $308, and 400 on Agency at $628. Fifty requests a day is fine for a research workflow and tight for anything automated. Check that number against your call pattern before you build.

Pros

• 16 platforms including Etsy, Amazon and YouTube
• API and MCP on every paid plan
• Autocomplete where no official API exists

Cons

• 50 requests a day on the $68 plan
• Daily caps suit workflows, not automation
• Autocomplete only, no real volume on most platforms

Pricing

Starter $68/month with 50 requests a day. Growth $148/month with 100. Scale $308/month with 200. Agency $628/month with 400. Annual billing saves over 20%. Enterprise available for custom limits. Web interface, MCP and API on every plan.

Best for marketplace and video sellers who need non-Google autocomplete. Skip it if you need high request volume.

7. Ahrefs API, Best for Index Size

Ahrefs is the choice when the keyword data has to sit next to backlink and traffic data from the same index.

API and MCP access are on every plan from Lite at $129 a month, worth noting if you remember the API being a separate enterprise product. You can query Site Explorer, Keywords Explorer and the rest programmatically on a normal subscription.

The constraint is rows, not calls. Max rows per request runs 100 on Lite, 250 on Standard at $249, 500 on Advanced at $449, and unlimited on Enterprise at $1,499. A hundred rows per request is a real limit: anything that wants a thousand keywords is ten calls and ten round trips.

Enterprise adds uncapped API access and custom endpoints, on annual commitment. Pay-as-you-go top-ups exist, and purchased credits last three billing months including the current one.

Use it when the question is “how hard is this keyword and who’s linking to the pages that rank”, because nothing cheaper answers both at once.

Pros

• API and MCP on every plan from $129
• Keyword, backlink and traffic data in one index
• Pay-as-you-go top-ups carry three months

Cons

• 100 rows per request on the $129 plan
• No free tier to test
• Uncapped access means $1,499 Enterprise

Pricing

Lite $129/month, Standard $249/month, Advanced $449/month, Enterprise $1,499/month on annual commitment. API and MCP on all. Max rows per request: 100, 250, 500, unlimited. Starter at $29 exists but is limited.

Best for teams who already pay for Ahrefs. Skip it if row limits would mean ten calls where you wanted one.

Keyword APIs for a Specific Platform

Most people searching for an Amazon or Etsy keyword API are looking for something that mostly doesn’t exist, and knowing that saves a week.

The structural problem: search volume is a number the platform has and almost never publishes. Google does, through Ads, because it sells those keywords. Amazon, Etsy, eBay and LinkedIn do not sell keyword access, so they do not expose it.

What exists instead:

• Amazon. No public keyword volume API. The Selling Partner API serves sellers with catalogue and order data, not keyword research. Third parties fill the gap: DataForSEO ships Amazon merchant endpoints and an Amazon database, Helium 10 and Jungle Scout sell their own, and Keyword Tool covers Amazon autocomplete.
• Etsy. The Etsy Open API handles listings and shop data, not search volume. eRank and Everbee are the specialists, and Keyword Tool covers Etsy autocomplete.
• YouTube. The YouTube Data API is official, free within a quota, and returns video and channel data rather than search demand. For what people type, you want autocomplete. vidIQ and TubeBuddy build on top of it.
• Google Search. There is no official keyword volume API for organic search. The closest free thing is the Search Console API, which gives you impressions, clicks and position for queries you already rank for. That’s the most undervalued free data source on this page.
• LinkedIn. Partner-gated APIs with no keyword volume product. Expect to work from autocomplete and inference.

Where scraping comes in. When no API exists, people build one. Apify is the usual platform for that: Free at $0 with $5 of credit, Starter $19 a month, Scale $199, Business $999, all plus usage at $0.2 down to $0.13 per compute unit. It’s a sensible route for autocomplete and listing data. It is not a route to search volume, because the number isn’t on the page to scrape.

Final Verdict: Which Keyword API Should You Use?

Every API here returns keywords. What separates them is the unit you’re billed in, and that decides your bill far more than the sticker price does.

Here’s the quick rundown after pricing all 7 on the same basis:

• Answer Socrates (Best overall): one request returns the whole grouped question set, so you pay per pull instead of per keyword, and MCP runs on the same credits
• DataForSEO (Best at scale): roughly $60 per million keywords of Google Ads volume, pay as you go
• Google Search Console (Best free): real query data for terms you already rank for, free and unlimited
• Google Ads (Best free): the original source, free, if you can live with volume ranges

Match the billing unit to your call pattern. Per-keyword pricing suits scripts that look up a few thousand terms. Per-request pricing suits anything pulling whole question sets or driving an AI agent. Row caps punish you when you wanted one big response, and daily request caps punish automation specifically.

Two situations flip the answer. If the site already gets impressions, start with Search Console rather than buying anything, because a query at position 11 is worth more than a thousand estimated volumes. And if you need backlinks beside the keywords, Ahrefs is the only one here that does both from one index.

Do this in the next ten minutes. Take the number of keywords you expect to pull in a month, and divide each plan’s price by it. The spread between the cheapest and most expensive answer on this page is about fourteen times, and the ranking almost never matches the order of the sticker prices.

FAQs

What is the best keyword research API?

Answer Socrates for question and cluster data, because one request returns the whole grouped set rather than a single keyword. DataForSEO for raw search volume at scale, at roughly $60 per million keywords. The Google Search Console API if you want real query data for a site you already own, free.

Is there a free keyword research API?

Yes, two, both from Google. The Search Console API is free and returns real query data, impressions and positions for sites you own, with no credit limit. The Google Ads API is also free with an Ads account, though volume comes as ranges unless you’re running active spend. Between them they cover keywords you already rank for and keywords you don’t.

How much does a keyword API cost?

It depends entirely on the billing unit. DataForSEO charges $0.06 per task covering up to 1,000 keywords. Keywords Everywhere charges one credit per keyword, from $84 a year for 100,000. Answer Socrates charges one request per pull whatever its size, from $39 a month. Those three models produce wildly different bills for the same workload.

Is there an Amazon or Etsy keyword API?

Not an official one for search volume. Amazon’s Selling Partner API and the Etsy Open API serve sellers with catalogue and listing data, not keyword demand. Third-party options cover the gap: DataForSEO has Amazon endpoints, Keyword Tool pulls autocomplete from both platforms, and eRank, Everbee, Helium 10 and Jungle Scout are the marketplace specialists.

Can I use a keyword API with ChatGPT or Claude?

Yes, and increasingly without writing code. Answer Socrates, Ahrefs, Keyword Tool and DataForSEO all ship MCP servers, which let an assistant call the API directly inside a conversation. Check the metering before you point an agent at one: an agent can make thirty calls in ninety seconds, and flat per-request pricing is much easier to cap than per-row billing.

Which keyword API should I pick for an AI agent or automation?

Pricing model matters more than data quality here, because agents call unpredictably. Flat per-request billing is the safest, since one call costs the same whether it returns 12 keywords or 900, and Answer Socrates works that way with free usage checks so the agent can monitor itself. Pay-as-you-go like DataForSEO is also forecastable, though you should set a spending cap before the first run. Avoid daily request caps, which is where Keyword Tool’s 50-a-day entry plan will stop an automation dead, and watch row limits like Ahrefs’ 100 rows on the $129 tier, which quietly turns one intended call into ten. Whatever you choose, make the agent report its own consumption after every run. You learn which prompts are expensive far faster than any invoice will tell you.