New: Public API — Access Your Crypto Tax Data Programmatically

We just launched something our power users have been asking for: a public API that lets you access your crypto tax data programmatically.

Whether you are building a custom portfolio tracker, feeding data into a spreadsheet, or integrating with your accounting workflow — you can now do it with a simple API key and standard HTTP requests.

What You Can Do

The API provides read-only access to four core endpoints:

• Portfolio — Current holdings with cost basis, live market values, and unrealized gains per asset
• Transactions — Your full transaction history with filtering by chain, type, asset, and date range. Paginated for large datasets.
• Tax Summary — Short-term and long-term gains/losses, total income (staking, airdrops, interest), fees, and disposal counts for any tax year
• Wallets — All connected wallets with chain, address, label, and transaction counts

There is also a write:tags scope that lets you create custom tags and assign them to transactions via the API — useful for automated workflows.

How It Works

Go to Settings → Data & Account → Public API and click "Create API Key." Give it a name, and you will see your full key exactly once — copy it and store it securely.

Then use it in any HTTP client:

curl -H "X-API-Key: bst_your_key_here" \
  https://blockchainsmarttax.com/api/v1/public/data/portfolio

That is it. No OAuth flows, no complex setup. One header, one request, your data.

Security and Rate Limiting

Every key is:

• SHA-256 hashed — we never store your key in plaintext
• Scoped — you choose which data the key can access
• Rate limited — 60 requests per minute per key (enforced via Redis)
• Revocable — one click to deactivate, takes effect immediately
• Tracked — you can see when each key was last used, from which IP, and total request counts

You can create up to 10 active keys per account. Each key shows usage analytics (requests today, this hour, and all-time) right in the settings page.

Static IP for Exchange Whitelisting

If your exchange requires IP whitelisting for API access, we now display our server’s static IP address right in the API key settings. Add 5.78.131.25 to your exchange’s allowlist and your transaction syncs will work without issues.

Full API Documentation

Hit the docs endpoint for the complete reference:

curl https://blockchainsmarttax.com/api/v1/public/docs

It returns all available endpoints, required scopes, parameters, and curl examples.

Use Cases

• Portfolio trackers — Pull your holdings into a custom dashboard or Google Sheet
• Accountant integrations — Your CPA can pull your tax summary without logging into your account
• Automated tagging — Use the write:tags scope to bulk-tag transactions from a script
• Tax planning tools — Query your gains throughout the year to estimate quarterly payments
• Multi-account monitoring — If you manage multiple accounts, aggregate data across them

This was one of the most-requested features from our community. If you build something cool with it, we would love to hear about it.