SEO APIs Explained, What Each One Returns and How to Choose

Effective SEO requires constant monitoring and analysis of many factors. While many SEO tools are available, they can be inconvenient for collecting data for large-scale projects or integrating their capabilities into existing software. APIs (application programming interfaces) are a more efficient solution in this case. They provide direct access to the data you need in a format that is easy to process.

The interesting question isn’t which API is best, because that depends on what you’re building. It’s what each one actually returns, what it costs to get at, and which of them you can even reach without an enterprise contract. This article answers those three for the APIs worth knowing, then covers how to choose between them.

What are SEO APIs?

SEO API is an interface that allows developers to integrate the functionality of third-party SEO services into their own applications. That covers keyword research, competitor analysis, site audits and anything else the vendor exposes.

SEO APIs typically provide more flexibility than using the services directly. A developer can pull search visibility, keyword rankings and competitor data straight into an application, and automate whatever the dashboard makes you click through.

Benefits of using SEO APIs

The data arrives current rather than as of the last export, which is what makes it useful for anything that has to react to a ranking change. The same call that tracks your own positions tracks a competitor’s.

Keyword work goes deeper through an API than through an export, since you can score search volume against competitiveness for a whole list in one pass instead of a page at a time.

The output drops into whatever you already run, from analytics to a CRM, without anyone exporting a spreadsheet first. That integration is the whole reason to reach for the API instead of the dashboard.

Which SEO API Returns What

Plenty of SEO tools exist and few of them offer API integration, so the field narrows quickly. Of those that do, access usually rides on a paid seat rather than being sold on its own.

Two things fall out of that table. Search Console is the only free source here, and it is also the only one reporting your own site as Google measured it rather than as a third party estimated it. And four of the six bill in units rather than requests, so the question to ask a vendor is what a single call to the endpoint you care about actually consumes.

HasData’s SERP API

HasData’s SERP API returns a parsed Google results page as JSON, which is what you’d otherwise build a scraper for. It tracks keyword rankings and reads what competitors rank for. In another article, we have covered how to use SERP API to track and check rankings in Google search results. Additionally, we have integrated this API into Google Sheets to make the data collection and analysis process even easier and more intuitive. The API returns a wealth of data, including:

1. URL, title and description for every organic result
2. SERP Snapshot
3. Most common SERP features:

• Knowledge Panel
• Knowledge Card
• People Also Ask
• Image Pack
• Local Pack
• Shopping Results
• Top Stories
• Top Sights
• Video

All of this data is returned in a convenient JSON format. Let’s see an example of the JSON response structure:

Signing up and verifying your email gives you 1000 free credits. A Google SERP request costs 10 of them, so that’s 100 searches, enough to see whether the response shape fits what you’re building.

Google Search Console API

Search Console is the only source on this page that reports your own site’s performance as Google measured it, not as a third party estimated it. Positions, clicks, impressions and CTR, straight from the index.

The Google Search Console API gives the same numbers to your code rather than to a chart, which covers:

1. Data collection. Positions and clicks, pulled on a schedule.
2. Indexation monitoring. The API can monitor your site’s indexation status and identify any problems.
3. Page optimization. The API can be used to identify pages that are not indexed, or that could be improved for search engines.

Access goes through a Google Cloud project with the API enabled. Authorisation is OAuth 2.0, not an API key, and a service account works for anything unattended. One credential reaches every property that account is verified on, so a single set of credentials covers a whole portfolio rather than one site.

MOZ API

The Moz API hands over Moz’s own link metrics so you can put them in your own tooling:

• Domain Authority
• Page Authority
• Spam Score
• Subdomain External Links
• Root Domain External Links
• External Equity Links
• All Links
• Root Domains Linking.

That covers link-building research and benchmarking against a competitor’s profile.

To get started with the Moz API, create a Moz account and generate an API key. The free tier is small, 50 rows a month at one request every ten seconds, which is a smoke test rather than a trial. Paid access starts at $20 a month and the ladder runs $20, $75, $125, $250, $500 and up, with per-row overage priced differently on each step.

Link analysis and competitor benchmarking are what it gets used for.

Ahrefs API

The Ahrefs API reads their own crawl index, which they report at over 90 billion pages. Backlinks, keyword data, rankings and the metrics Ahrefs derives from them all come out of it. Ahrefs is also one of the most popular and widely used SEO platforms due to its wide range of features.

API v2 is gone and v3 is what you get today. Anything written against apiv2.ahrefs.com needs rewriting rather than porting, because the host, the auth and the response shape all changed.

Billing is the part to read before you build. v3 charges in API units, the minimum for any request is 50 units, and consumed units are not refunded. Some endpoints are free and say so on their own documentation page, and every plan carries a small allowance of free test queries, so you can see the response shape before committing. On plans that allow it, going over the included limit bills automatically, which is the setting to cap first.

Remember, to use any Ahrefs API, you should create an Ahrefs account and purchase an API subscription. You will then receive a token that you need to use to authenticate API requests.

Semrush API

Semrush API is a tool that allows you to integrate the features of the SEO service into your own application. Semrush suits automated reporting across domains, keywords, backlinks and traffic estimates. Depending on your needs, you can choose from one of the two available APIs:

• Standard API Package. This package includes all of the core Semrush analytics and project management features.
• Traffic Analytics API. This package is designed to get information about website traffic.

Access needs a Business subscription, which is $549 a month, and API calls then draw on a unit balance on top of that. Units are priced by what you ask for, so a line of historical data costs 50 units where the same line of current data costs 10. Budget the units separately from the seat.

Majestic API

Majestic is a link index. It reports a site’s backlink profile, the number and quality of the links pointing at it, and its own two metrics, Citation Flow and Trust Flow.

The API covers domains, pages, links and the anchor text on them. It is a great tool for analyzing a website’s backlink profile or tracking changes. It can also be useful for link-building tasks such as finding or building new links.

However, full access to the Majestic data set is only available with a paid subscription. This means that even using the Majestic service directly, you can only access a partial data set.

Reading a Majestic Report Without the API

Majestic renders the summary metrics for a domain on its own report pages, and a report page is ordinary HTML. Where a project needs those numbers occasionally rather than in bulk, fetching the rendered page with a web scraping API and reading the fields out of it is one route, and it stays inside whatever Majestic’s terms allow for the account doing the fetching. For anything continuous, the API is the supported path and the one that comes with a contract.

To demonstrate how such a script works, we have written a small example in Python that you can run directly on the colab research page. To do this, you should replace the data in the second code block with your HasData API key and paste the link to the website you want to analyze.

Then, run each block of code one by one.

The run writes two files, JSON and CSV, holding what the Web Scraping API read off the page. To find your saved files, look in your project folder:

The JSON comes out in this shape, shortened here, so a real run returns considerably more:

{
    "numberOfExternalOutLinks": 3,
    "numberOfInternalOutLinks": 35,
    "nonUniqueLinks": {
        "total": 101,
        "numberOfDeletedLinks": 17,
        "numberOfNoFollowLinks": 33
    },
    "primaryTopic": "Business/Marketing and Advertising",
    "refDomainCounts": {
        "follow": 40,
        "https": 53
    }
}

You can copy this script, modify it for your needs, use it online, or embed it in your project.

How to Choose the Right SEO API

Four questions, in this order.

The first step is to understand what you need the API to do. This will help you understand what functionality you want from the API. Once you understand your needs, you can narrow your options.

Once you understand your needs well, you can evaluate different APIs’ capabilities. Match it against the job, whether that is keyword research, competitive analysis, site auditing, rank tracking or integration into a tool you already run.

SEO APIs can range in price from free to hundreds of dollars per month. It’s important to compare prices before you make a decision. You should also consider the level of support offered by the API provider.

Before you commit to an SEO API, it’s a good idea to test it out. This will show whether it works with your project and meets your needs. Here are some additional tips for choosing the best SEO API:

• Read reviews from other users.
• Contact the API provider to ask questions.
• Start with a free or low-cost plan.

What You Can Build With Them

SEO APIs provide developers with a convenient way to create data-driven website analysis tools. They offer access to data in a structured format that can be used to automate tasks, gain insights, and improve website performance.

Keyword Research and Analysis

One of the many ways to use SEO APIs is to identify relevant keywords and phrases for audience analysis. These tools provide up-to-date data on keyword competition and search volume, with enough history to see which way a term is moving, which can be used to automate targeted SEO strategies to help you rank higher on search engine results pages.

The best choice is the SERP and Ahrefs APIs.

Rank Tracking and Monitoring

SEO APIs allow you to track your website’s ranking for specific keywords over time. Using an API instead of a service allows you to receive data in a format already ready for further processing, which can help reduce the workload on SEO professionals.

Using a rank tracker is one of the most important tools for SEO work. It allows you to track not only the dynamics of changes in your website’s ranking but also to take timely action in case of a decline in positions. In addition, using an SEO API, you can create your own flexible tool for tracking changes, periodic notifications, or automatic data collection over a long period of time.

The best choice is the Google Search Console and SERP APIs.

Backlink Analysis and Management

Backlinks are one of the most important ranking factors in SEO, and they can be analyzed using SEO APIs. Search engines use backlink analysis to rank websites more effectively, determining the most useful resources.

Continuous backlinks monitoring can help you analyze your website’s backlink profile and understand the context in which your resource is linked.

SEO APIs can be used to create specialized tools for automating the collection and analysis of backlinks. You can integrate these tools into your application and, for example, automatically analyze the type of backlink and the context of its use.

By timely identifying and analyzing backlinks and their quality, you can improve your website’s backlink profile.

The best choice is the Ahrefs and Semrush APIs.

Technical SEO Audits and Optimization

Another use of SEO APIs is to develop applications for analyzing and optimizing websites for search engines using technical SEO. An audit on a schedule catches broken links and duplicate content before anyone reports them. This information can be used to improve the content and indexability of your website.

The best choice is the Google Search Console and PageSpeed Insights APIs.

Content Optimization and Generation

SEO APIs can also optimize your website’s content for search engines. They can also provide data on keyword density and readability of your content. This information can be used to improve the quality of your content and boost its ranking in SERPs.

In addition to these specific apps, SEO APIs can automate tasks such as creating sitemaps and submitting websites to search engines. They can also integrate SEO data into other applications, such as marketing automation platforms and CRM systems.

The SERP API answers this one, and Semrush or Ahrefs adds the historical side.

Conclusion

An SEO API turns a dashboard into something your own code can query. The six covered here, HasData’s SERP API, Google Search Console, Moz, Ahrefs, Semrush and Majestic, each answer a different question, and most projects end up using two of them rather than one.

Between them they cover rankings, traffic, keyword data and backlinks.

Which one fits depends on what you’re building. The practical limit is usually the access tier rather than the data, so read the pricing page before the documentation.