Accounts - Mithril

Mithril’s tenancy has three levels:

Workspace — your organization. Created automatically on signup.
Subaccount — an isolated strategy or client, each with its own attached exchange credentials, positions, and risk limits.
Credentials — your Kalshi API key or Polymarket wallet key, attached to a subaccount, envelope-encrypted, used only to sign orders.

Isolating strategies in subaccounts means a runaway bot in one can’t touch the capital or limits of another.

List subaccounts

Most calls take a subaccount_id. Discover yours instead of hardcoding it:

curl https://api.trymithril.com/v1/subaccounts \
  -H "Authorization: Bearer $MITHRIL_API_KEY"

subs = s.get(f"{BASE}/v1/subaccounts").json()["data"]
sub_id = subs[0]["id"]

A subaccount (SubaccountView):

{
  "data": [
    {
      "id": "sub_wdzt3wugmlu4kadia7nuc2dz",
      "workspace_id": "ws_kit2532bcugmo2opqqxrkb7p",
      "name": "main",
      "created_at": "2026-07-16T14:30:00Z"
    }
  ],
  "next_cursor": null,
  "has_more": false
}

Unified balances

GET /v1/subaccounts/{id}/balances returns the full, live balance set in one page — normalized across venues (USDC on Polymarket, USD on Kalshi):

curl https://api.trymithril.com/v1/subaccounts/sub_.../balances \
  -H "Authorization: Bearer $MITHRIL_API_KEY"

bal = s.get(f"{BASE}/v1/subaccounts/{sub_id}/balances").json()["data"]
for b in bal:
    print(b["asset"], b["available"], b["total"])

Each balance (BalanceView):

{ "data": [ { "asset": "USDC", "total": "1042.50", "available": "1042.50" } ], "has_more": false }

Create a subaccount

POST /v1/subaccounts seeds the standard guardrails by default. Set disable_guardrails: true to opt out of all protection.

curl -X POST https://api.trymithril.com/v1/subaccounts \
  -H "Authorization: Bearer $MITHRIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "name": "momentum-bot", "disable_guardrails": false }'

Attach exchange credentials

PUT /v1/subaccounts/{id}/credentials. The body depends on the venue — but private_key is always write-only and never returned by any endpoint.

{
  "exchange": "polymarket",
  "wallet_address": "0xabc...",
  "private_key": "0x...",
  "public_fields": {}
}

{
  "exchange": "kalshi",
  "api_key_id": "a1b2c3d4-...",
  "private_key": "-----BEGIN RSA PRIVATE KEY-----\n...\n-----END RSA PRIVATE KEY-----",
  "public_fields": {}
}

exchange

string

required

polymarket or kalshi.

wallet_address

string

Polymarket: your wallet address (the signing identity).

api_key_id

string

Kalshi: your API key ID; private_key is its PEM-encoded RSA key.

private_key

string

required

Write-only signing secret. Envelope-encrypted at rest, decrypted only in memory to sign an order, never logged, never returned.

Credentials are write-only. Once attached they are never returned by any endpoint — every secret field is redacted in responses.

Next: Market data

Find markets and read the book before you trade.

​List subaccounts

​Unified balances

​Create a subaccount

​Attach exchange credentials

Next: Market data

List subaccounts

Unified balances

Create a subaccount

Attach exchange credentials