AT Protocol PLC Directory Counter #

Count and analyze AT Protocol accounts by scanning all PDS (Personal Data Store) servers via the PLC directory.

Used to generate the stats at sifa.id/stats. See the methodology for a full explanation of what is and isn't counted.

What It Does #

• Crawls the entire PLC directory (~87M DID registrations as of April 2026)
• Counts accounts per PDS provider
• Tests reachability by sampling handles and resolving them via the AT Protocol identity system
• Exports CSV time-series data for daily and all-time views

Scripts #

Script	Purpose	Runtime
count-plc-dids.ts	Full crawl of plc.directory, builds all CSVs	2–3 hours
recheck-reachability.ts	Reachability scan using plc-count-results.json (standalone workflow)	~7 hours
check-reachability.ts	Reachability scan reading/writing the NAS CSV format (production workflow)	~7 hours

Quick Start #

Prerequisites #

• Node.js 18+ (needs native fetch)
• tsx (TypeScript runner): npm install -g tsx

Run the Counter #

# Full crawl (2-3 hours)
npx tsx count-plc-dids.ts

# Resume if interrupted
npx tsx count-plc-dids.ts --after 2025-09-02

Run Reachability Check (Optional, ~7 hours) #

# Standalone workflow (reads plc-count-results.json)
npx tsx recheck-reachability.ts

# NAS/production workflow (reads/writes plc-count-by-pds.csv directly)
npx tsx check-reachability.ts

Output Files #

File	Description
plc-count-results.json	Summary stats, PDS breakdown
plc-count-by-pds.csv	Per-PDS totals + reachability %
plc-count-by-pds-daily.csv	Daily time-series by PDS
data/plc-reachability-through.txt	Date of last reachability scan (NAS workflow)

Key Findings (April 2026) #

Metric	Count
Total did:plc	~87M
Unique PDS hosts	~16K
Bluesky (bsky.social + *.bsky.network)	~61M
Self-hosted / other	~23M (dominated by ~22M pds.trump.com bot accounts)

Note: our total is higher than Bluesky's reported active user count (~33–36M) because we count every identity ever registered in the PLC directory, including bots, spam, and deleted/deactivated accounts. See the methodology for details.

How It Works #

1. Crawl: Pages through plc.directory/export (1000 ops/page)
2. Filter: Counts genesis ops (prev=null) = new DIDs
3. Track: Extracts PDS endpoint from each operation
4. Sample: Tests 3–50 handles per PDS (scaled to host size) for reachability
5. Export: Writes CSVs with daily breakdowns

Rate Limiting #

• 75ms delay between pages
• Handles 429s with 10s backoff
• Reachability checks: 50ms between handle resolves

License #

MIT