Limits & Access

Plans

ChessGrammar offers a free tier and paid tiers. Free is unauthenticated and rate-limited per IP; paid tiers use an API key and unlock higher throughput.

Scale also includes priority email support. Custom plans cover dedicated infrastructure, on-premise, or volume agreements — get in touch.

Current prices are introductory. Early subscribers keep their rate locked when prices increase with the v3 engine release.

Rate limit responses

When a rate limit is exceeded, the API returns HTTP 429:

{"error": "Rate limit exceeded"}

For the free tier's daily game analysis cap:

{"error": "Daily game analysis limit reached. Upgrade for higher limits."}

Getting an API key

1. Go to Pricing and choose Builder or Scale.
2. Complete checkout via Stripe.
3. Your API key (cg_…) is issued immediately and visible in your dashboard.
4. Send it on every request to api.chessgrammar.com/v1 in the Authorization header:

curl -X POST https://api.chessgrammar.com/v1/extract \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer cg_YOUR_API_KEY" \
  -d '{"fen": "..."}'

Treat your key like a password — do not commit it to source control or expose it client-side.

Best practices

• Use L1 for bulk scanning — fast structural scan suits high-volume position screening
• Two-pass analysis — scan with L1 first, then call L2 only on positions where L1 found candidates
• Cache results — the API is deterministic; the same FEN always returns the same result
• Filter by pattern — use the patterns parameter to reduce response size when you only need specific tactics

Need more?

• Pricing — compare plans and subscribe
• Contact — talk to us about Custom or volume agreements