Build on Brix.

Quickstart

1. Sign in to Brix and open Developers → API keys. Name the key, pick only the permissions you need, and copy it. It’s shown once.
2. Store it as an environment variable on your server, e.g. BRIX_API_KEY. Never put it in a web page, a mobile app bundle, or a public repo.
3. Make your first call:

curl https://www.usebrix.app/api/v1/me \
  -H "Authorization: Bearer $BRIX_API_KEY"

const res = await fetch("https://www.usebrix.app/api/v1/charges/upcoming?days=7", {
  headers: { Authorization: `Bearer ${process.env.BRIX_API_KEY}` },
});
if (!res.ok) throw new Error((await res.json()).error.message);
const { data } = await res.json();
for (const c of data)
  console.log(`${c.merchant}: $${c.amount} on ${c.next_date}`);

import os, requests

r = requests.post(
    "https://www.usebrix.app/api/v1/reminders",
    headers={"Authorization": f"Bearer {os.environ['BRIX_API_KEY']}"},
    json={"merchant": "Spotify", "when": "2 days before"},
    timeout=10,
)
r.raise_for_status()
print(r.json()["remind_at"])

Authentication & permissions

Send the key as a bearer token: Authorization: Bearer brix_sk_…. Brix stores only a SHA-256 hash of it. Each user can have up to 5 active keys; revoking one stops it immediately. Each key carries scopes, and an endpoint without its scope returns 403 insufficient_scope.

Conventions

Base URL

https://www.usebrix.app/api/v1

Format

JSON in and out, snake_case fields, amounts in USD as decimal numbers, dates as YYYY-MM-DD. Lists come back as { "object": "list", "data": [...] }.

Rate limit

120 requests per minute per key. Every response includes X-RateLimit-Limit and X-RateLimit-Remaining; a 429 includes Retry-After.

Retries

POST /trials accepts an Idempotency-Key header; repeating it returns the first result. Creating the same reminder twice is already safe.

Versioning

Responses carry Brix-Version: 2026-10-24. We add fields without notice; we never remove or rename fields within /v1.

Request IDs

Every response has an X-Request-Id, also inside error bodies. Include it when you report a problem.

Errors

{
  "error": {
    "type": "insufficient_scope",
    "message": "This key is missing the `charges:write` scope.",
    "request_id": "req_4f1c9a0b2e7d4c3a8b19"
  }
}

Endpoint reference

The full machine-readable spec is at /api/v1/openapi.json (OpenAPI 3.1). Import it into Postman, Insomnia, or a client generator.

• GET/meCheck your key
• GET/chargesList charges
• GET/charges/upcomingUpcoming charges
• GET/charges/{id}Get a charge
• PATCH/charges/{id}Mark to cancel / reactivate
• POST/trialsAdd a free trial
• GET/summarySpending summary
• GET/remindersList reminders
• POST/remindersCreate a reminder
• DELETE/reminders/{id}Delete a reminder
• GET/cardsList cards
• GET/newsMerchant news
• GET/refundsList refunds
• GET/practicePractice portfolio

curl "https://www.usebrix.app/api/v1/me" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/charges?status=active" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/charges/upcoming?days=7" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/charges/ch_123" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl -X PATCH "https://www.usebrix.app/api/v1/charges/ch_123" \
  -H "Authorization: Bearer $BRIX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"status":"to_cancel"}'

curl -X POST "https://www.usebrix.app/api/v1/trials" \
  -H "Authorization: Bearer $BRIX_API_KEY" \
  -H "Idempotency-Key: trial-notion-nov" \
  -H "Content-Type: application/json" \
  -d '{"merchant":"Notion AI","end_date":"2026-11-15","amount":10}'

curl "https://www.usebrix.app/api/v1/summary" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/reminders" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl -X POST "https://www.usebrix.app/api/v1/reminders" \
  -H "Authorization: Bearer $BRIX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"merchant":"Spotify","when":"2 days before"}'

curl -X DELETE "https://www.usebrix.app/api/v1/reminders/manual:…" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/cards" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/news" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/refunds" \
  -H "Authorization: Bearer $BRIX_API_KEY"

curl "https://www.usebrix.app/api/v1/practice" \
  -H "Authorization: Bearer $BRIX_API_KEY"

What the API doesn’t do, and why

• Create cards. A card is a payment instrument, so it needs the user’s confirmation in the app (and their PIN for voice). The API can list cards, masked to the last four digits.
• Link banks. Bank linking runs through Plaid’s secure screen in the app. Linked charges show up in /charges with source: "plaid".
• Chat with the assistant. Each conversation runs a language model, which costs money per message, so it stays in the app, WhatsApp, and voice.
• Cancel at the merchant. Brix never cancels or moves money. Marking a charge to_cancel records the decision and returns the merchant’s cancel link.
• Act for other people. Keys are personal. There’s no OAuth for third-party apps yet; build for yourself, or have each user paste their own key.

Run it yourself

Brix is open source. The code, setup guide and tests are on GitHub. A local copy runs as a demo with sample data and no accounts.

git clone https://github.com/Timeless-Dave/brix
cd brix
npm install
cp .env.example .env.local
npm run dev

Environment variables

Names from .env.example. Leave a provider’s values empty to keep that integration off.