Overview

Welcome to the Synci API. Synci lets you fetch, transform, and transfer your banking & financial data anywhere, and the API gives you programmatic access to everything the Synci dashboard can do: accounts, balances, transactions, investment holdings, bank connections, transfer links, rules, destinations, and webhooks.

Base URL:  https://api.synci.io
API root:  https://api.synci.io/api/v1

The API is REST-based and served over HTTPS only. Requests and responses use JSON, except where noted (the OAuth token endpoint uses form encoding). Send an Accept: application/json header with every request.

What you can build

Custom reporting and dashboards: pull transactions, balances, and holdings across all of a user's connected banks, brokerages, and crypto exchanges.

Automations: trigger workflows from webhooks when new transactions arrive or balances change.

Integrations: build an OAuth app so other Synci users can securely share their financial data with your product.

Housekeeping: manage bank connections, transfer links, and rules programmatically.

Authentication at a glance

All requests are authenticated with a Bearer token:

Authorization: Bearer YOUR_ACCESS_TOKEN

There are two ways to get a token:

You are building...	Use	Where
Scripts or a server-to-server integration for your own Synci account	Personal access token	Dashboard → Developers → Tokens
An app that other Synci users authorize	OAuth 2.0 app (authorization code + PKCE)	Dashboard → Developers → Apps

See Authentication for details, and Building OAuth apps for the full OAuth guide.

Quick start

Generate token

In the Synci dashboard, go to Developers → Tokens and create a personal access token. Copy it right away; it is shown only once.

List your accounts

Fetch transactions booked since June 1st

Core resources

Resource	What it is
Financial connections	A link to one institution (a bank, brokerage, or crypto exchange). Has a health status: `HEALTHY`, `FAILING`, or `DEAD`.
Financial accounts	The individual accounts under a connection (checking, savings, credit, investment).
Balances	Balance snapshots per account, with type and reference date.
Transactions	Booked and pending transactions, with rich detail, enrichment, and (for brokerages) trade data.
Holdings	Current investment and crypto positions per account (symbol, quantity, market value).
Transfer links	Connect a financial account to a destination (YNAB, Lunch Money, Google Sheets) so data flows automatically.
Transfer logs	The record of every transfer attempt, with undo support.
Rules	Conditions and actions that categorize or transform transactions, either persisted in Synci or applied during transfer.
Destinations	Your connected destination apps and their accounts.
Webhook endpoints	Your HTTPS endpoints that receive event notifications.

The full endpoint reference (every path, parameter, and response schema, with in-browser request testing) is in the API Reference section of these docs.

Guides

Authentication: personal access tokens, OAuth tokens, and scopes.

Building OAuth apps: register an app and implement the authorization flow.

Webhooks: event types, payloads, signature verification, and retries.

Pagination, filtering, and sorting: how list endpoints work.

Errors: response format and status codes.

Rate limits: request limits and how to handle 429 responses.

MCP: Connect AI assistants: give AI tools read-only access to your financial data.

Versioning

The current API version is v1, and all documented endpoints live under /api/v1. We treat the following as non-breaking and may ship them without notice: adding new endpoints, adding new optional request parameters, adding new fields to responses, and adding new webhook event types (you only receive events you subscribe to). Breaking changes
will be announced ahead of time.

Getting help

Help center: help.synci.io

Dashboard: manage tokens, apps, and webhooks under Developers in your Synci account.

What you can build#

Authentication at a glance#

Quick start#

Core resources#

Guides#

Versioning#