Google Developer Knowledge API

Direct REST API access to Google’s public developer documentation without needing the MCP server.

Overview

The Developer Knowledge API provides machine-readable access to Google’s developer docs. It offers:

• SearchDocumentChunks: Find relevant page URIs and content snippets
• GetDocument: Fetch full content of a single document
• BatchGetDocuments: Fetch multiple documents at once

Authentication

IMPORTANT: Despite official documentation suggesting API keys work, the API actually requires OAuth2 authentication (access tokens or ADC).

Option 1: Application Default Credentials (Recommended)

1. Install gcloud CLI if not already installed
2. Run:

   gcloud auth application-default login
   

3. Enable the API in your project:
   • Open Developer Knowledge API page
   • Select your project and click Enable

Option 2: Service Account

1. Create a service account in Google Cloud Console
2. Download the JSON key file
3. Set the environment variable:

   export GOOGLE_APPLICATION_CREDENTIALS="/path/to/service-account.json"
   

Option 3: Access Token

Get a token manually:

gcloud auth application-default print-access-token

API Reference

Base URL: https://developerknowledge.googleapis.com/v1alpha

All requests require an Authorization: Bearer <token> header.

Search for Document Chunks

GET /documents:searchDocumentChunks?query={query}

Parameters:

• query (required): Search query string
• pageSize (optional): Number of results per page
• pageToken (optional): Token for pagination

Response includes:

• documentChunks[]: Array of matching chunks
  • parent: Document identifier (use for GetDocument)
  • content: Snippet of matching content
  • uri: Original documentation URL

Get Single Document

GET /{document_name}

Parameters:

• document_name: The parent value from search results (e.g., documents/developers.google.com/...)

Response: Full Markdown content of the document

Batch Get Documents

POST /documents:batchGet

Body (JSON):

{
  "names": [
    "documents/developers.google.com/path/to/doc1",
    "documents/developers.google.com/path/to/doc2"
  ]
}

Retrieves up to 100 documents in a single call.

Python Client

See scripts/developer_knowledge_client.py for a ready-to-use Python client with automatic OAuth2 handling.

Installation Requirements

pip install google-auth google-auth-httplib2

Or use the gcloud CLI fallback (no extra dependencies).

Quick Usage

from developer_knowledge_client import DeveloperKnowledgeClient

# Uses Application Default Credentials automatically
client = DeveloperKnowledgeClient()

# Search for documentation
results = client.search("Cloud Storage buckets")
for chunk in results.get("documentChunks", []):
    print(f"URL: {chunk.get('uri')}")
    print(f"Content: {chunk.get('content')[:200]}...")

# Get full document
doc = client.get_document(chunk["parent"])
print(doc.get("content"))

Explicit Authentication

# Using service account
client = DeveloperKnowledgeClient(service_account_file="/path/to/sa.json")

# Using explicit access token
client = DeveloperKnowledgeClient(access_token="ya29.xxxx")

Convenience Method

# Search and fetch full documents in one call
docs = client.search_and_get("Firebase authentication", max_results=3)
for doc in docs:
    print(doc["content"])

cURL Examples

Get Access Token

export TOKEN=$(gcloud auth application-default print-access-token)

Search

curl -H "Authorization: Bearer $TOKEN" \
  "https://developerknowledge.googleapis.com/v1alpha/documents:searchDocumentChunks?query=BigQuery"

Get Document

curl -H "Authorization: Bearer $TOKEN" \
  "https://developerknowledge.googleapis.com/v1alpha/documents/developers.google.com/path/to/doc"

Covered Documentation

The API indexes these Google developer sites:

• developer.android.com (Android)
• firebase.google.com (Firebase)
• docs.cloud.google.com (Google Cloud)
• ai.google.dev (Gemini API / Google AI)
• developers.google.com (Ads, Maps, YouTube, etc.)
• developer.chrome.com (Chrome)
• developers.home.google.com (Google Home)
• www.tensorflow.org (TensorFlow)
• web.dev (Web)
• fuchsia.dev (Fuchsia)

Limitations

• Authentication: Requires OAuth2 (API keys do NOT work despite documentation)
• Markdown Quality: Generated from HTML, may have formatting issues
• Content Scope: Only public documentation pages, no GitHub/OSS/blogs/YouTube
• Data Freshness: Re-indexed within 24 hours of publication

When to Use This Instead of MCP

Use direct API calls when:

• MCP authentication is failing or not configured
• You need more control over request/response handling
• You’re integrating into a pipeline that doesn’t support MCP
• You want to use the API in a standalone script
• You need to handle OAuth2 tokens explicitly

Official Documentation

• API Overview
• Quickstart
• Corpus Reference