Lighthouse & On-Page SEO API
Get any page's performance, accessibility, best-practices and SEO scores, its Core Web Vitals and its failed audits in one request. The same endpoint audits the page for SEO and extracts its main content as sections or Markdown.
import requests
response = requests.post(
"https://data.semust.com/v1/on-page",
headers={
"SEMUST-API-USER": "your_username",
"SEMUST-API-PASSWORD": "your_password",
},
json={
"type": "lighthouse",
"url": "https://www.example.com/",
"device": "mobile",
"language": "tr",
},
timeout=90, # longer than ?wait= (60 seconds by default)
)
data = response.json()
if response.status_code == 202:
# Still running: collect it later from data["poll_url"]
print(f"Task {data['task_id']} is still running")
elif response.status_code == 200:
page = data["data"]
print("Scores:", page["scores"])
print("LCP:", page["metrics"]["largest_contentful_paint_ms"], "ms")
for audit in page["failed_audits"][:5]:
print(audit["category"], "-", audit["title"])
else:
# e.g. PAGE_BLOCKED: the site refused the audit (not charged)
print(data["code"], data["error"])
Meet Semust, trusted by 12.000+ brands.
One Endpoint
lighthouse, audit and content are picked with the `type` parameter. One request shape, one authentication, one error format.
Results, Not a Raw Report
Instead of a raw Lighthouse report hundreds of kilobytes long, you get 0–100 scores, metrics in milliseconds and failed audits ranked by their savings.
Flat Price
$0.0055 per page for Lighthouse, $0.000165 for an SEO audit ($0.00165 with JavaScript rendering) and $0.000165 for content extraction.
What Can You Do with the On-Page API?
Measure page performance, technical SEO and content with the data.semust.com/v1/on-page endpoint.
lighthouse returns the performance, accessibility, best-practices and SEO scores, the Core Web Vitals and the failed audits. audit returns the page score, meta tags, headings, content measures, links, size, load time and the issues found. content extracts the page's main content as heading-and-text sections, or as Markdown on request. All three share one request shape and one authentication.
// One endpoint, three reports
POST /v1/on-page
{ "type": "lighthouse", "url": "https://www.example.com/", "device": "mobile" }
{ "type": "audit", "url": "https://www.example.com/", "javascript": true }
{ "type": "content", "url": "https://www.example.com/blog/", "markdown": true }
// Languages the audit titles can be returned in (free)
GET /v1/on-page/languagesOne platform,Organic success stories:
Batuhan Durmaz
SEO Specialist
SEMUST is a powerful tool for SEO professionals. It provides valuable data in a simple and easy‑to‑understand format, making it a great choice for both local and global projects. I use it for keyword analysis, Google Search Console data, ranking tracking, and content creation. I'm very satisfied with it.
Selen Çetin
SEO Specialist
I first came across Semust on LinkedIn, back when it was just starting to gain attention. Curious, I decided to give it a try—and it’s now become one of my favorite tools. What I appreciate most is how it handles many tasks that I used to perform manually with a single click, which makes my job significantly easier. Seeing how quickly it has evolved since the first time I used it also inspires confidence.
Aykut Özcan
SEO Director – Digital UP
At Digital UP SEO Agency, we rely heavily on the analysis and reporting tools Semust provides throughout our SEO workflows. From keyword tracking and competitor analysis to site‑health scans and backlink audits, it brings both speed and depth to many critical areas. Thanks to the comprehensive, data‑driven insights it offers, we consistently boost our clients' search‑engine performance. Semust is a powerful partner on our agency's growth journey.
On-Page API Frequently Asked Questions
More organic traffic
- 14-day free trial
- No setup required
- Search Console integration