# Atomic Docs

> Developer documentation for Atomic's UserLink (payroll connectivity: Deposit, Verify) and PayLink (merchant connectivity: Switch, Manage) products, the Transact SDK, the REST API, webhooks, and the Manage agent tool definitions.

Important context:

- UserLink connects payroll providers. Deposit switches direct deposit; Verify returns income and employment data.
- PayLink connects merchants and subscription services. Switch updates the payment method on file; Manage reads bills and runs actions such as cancel and pause.
- Every integration has the same shape: your server creates an access token for a user, your app opens Transact with the returned publicToken, the user signs in inside Transact, and results arrive as Transact events on the client and as task-status-updated webhooks or API reads on the server.
- Authenticate API calls with the x-api-key and x-api-secret headers. Build against the sandbox environment before production.
- Users enter payroll and merchant credentials only inside Transact. Do not collect passwords or one-time codes in your own UI or agent.
- UserLink and PayLink have separate reference pages for the SDK, API, and webhooks. Read the reference for the product you are integrating.
- Each page link below ends in .md and returns the page as Markdown. Drop the suffix for the HTML page.

Common integration flows:

- Deposit switch: create an access token, open Transact for a deposit task, handle the onFinish and onClose events, then confirm the switch from the task-status-updated webhook.
- Payment method switch: create an access token, open Transact for a Switch task at the merchant, then confirm the result from the task-status-updated webhook.
- Subscription cancellation from an AI agent: upsert the user, find the company with the pay-link scope, get the actions for the company and user, build a Transact config with the chosen action ID for the app to open, store task webhooks, then read the user's subscriptions after the follow-up refresh to confirm the plan status or scheduled cancellation.

## Overview

- [Home](https://docs.atomicfi.com/index.md): Developer documentation for Atomic's UserLink and PayLink products, the Transact SDK, the REST API, and webhooks.
- [UserLink](https://docs.atomicfi.com/userlink.md): Payroll connectivity. Users sign in to their payroll provider to switch direct deposit or share income and employment data.
- [PayLink](https://docs.atomicfi.com/paylink.md): Merchant connectivity. Users sign in to merchants and subscription services so you can sync bills, update payment methods, and run actions.

## UserLink Products

- [Deposit Plan Your UX](https://docs.atomicfi.com/products/deposit/plan-your-ux.md): Design the screens around a direct deposit switch: intro, incentive messaging, and what to show after Transact closes.
- [Deposit Best Practices](https://docs.atomicfi.com/products/deposit/best-practices.md): Conversion levers for deposit switching: incentives, manual switches, and fractional deposits.
- [Deposit Implementation Guide](https://docs.atomicfi.com/products/deposit/implementation.md): Launch Transact for a deposit switch, handle task events, and confirm the switch through webhooks.
- [Verify Plan Your UX](https://docs.atomicfi.com/products/verify/plan-your-ux.md): Design the screens around income and employment verification and set user expectations before Transact opens.
- [Verify Data Scoping](https://docs.atomicfi.com/products/verify/data-scoping.md): Choose which employment and income fields Atomic returns for your use case in the Console.
- [Verify Implementation Guide](https://docs.atomicfi.com/products/verify/implementation.md): Launch Transact for verification, handle task events, and receive payroll data through webhooks and the API.

## UserLink Guides

- [Search & Deeplink](https://docs.atomicfi.com/guides/search-and-deeplinking.md): Hub for getting a user to the right company: search experiences, backend company search, and deeplinking.
- [Search Experiences](https://docs.atomicfi.com/guides/search-experiences.md): Customize the tiles on the popular tab in Transact search for different audiences.
- [Deeplink to Login Page](https://docs.atomicfi.com/guides/deeplink-to-login.md): Combine Company Search with the Transact deeplink parameter to start a user at the login step.
- [Transact Events](https://docs.atomicfi.com/guides/transact-events.md): Events the Transact SDK emits as a user moves through the flow and how to consume them.
- [Best Practices for Re-engagement](https://docs.atomicfi.com/guides/transact-events/best-practices-for-re-engagement.md): Use Transact events to bring back users who did not convert.
- [Create a Conversion Funnel](https://docs.atomicfi.com/guides/transact-events/create-a-conversion-funnel.md): Build a funnel from Transact events to see where users drop off.
- [Just-In-Time (JIT) Flow](https://docs.atomicfi.com/guides/jit-flow.md): Send sensitive account data to Atomic only when the task needs it, through the onDataRequest handler.
- [Webhooks Guides](https://docs.atomicfi.com/guides/webhooks.md): Hub for receiving Atomic events over HTTP: setup, testing, and securing endpoints.
- [How to Secure Webhook Endpoints](https://docs.atomicfi.com/guides/webhooks/how-to-secure-webhook-endpoints.md): Verify the HMAC signature on each delivery and reject anything else.
- [How to Set Up Webhooks](https://docs.atomicfi.com/guides/webhooks/how-to-set-up-webhooks.md): Create webhook endpoints and subscribe to events in the Atomic Console.
- [How to Test Webhook Endpoints](https://docs.atomicfi.com/guides/webhooks/how-to-test-webhook-endpoints.md): Send sample event data to an endpoint from the Console.
- [Security Guides](https://docs.atomicfi.com/guides/security.md): Hub for the security controls beyond TLS and API keys: mutual TLS and request body encryption.
- [Mutual TLS for API Requests](https://docs.atomicfi.com/guides/security/mtls-for-api-requests.md): Present a client certificate on requests to the Atomic API.
- [Mutual TLS for Webhooks](https://docs.atomicfi.com/guides/security/mtls-for-webhooks.md): Require and verify the client certificate Atomic presents when delivering webhooks.
- [Request Body Encryption (JWE)](https://docs.atomicfi.com/guides/security/request-body-encryption.md): Encrypt API request bodies with your account's public key before they leave your systems.

## UserLink Integrations

- [CoAuth Integration](https://docs.atomicfi.com/integrations/co-auth.md): Atomic's first-party integration with payroll providers for a faster, API-based connection.
- [Coverage Explorer](https://docs.atomicfi.com/coverage-explorer.md): Explore income and employment data coverage across payroll providers.

## UserLink Reference

- [UserLink Transact SDK Reference](https://docs.atomicfi.com/reference/transact-sdk.md): Install and initialize Transact on web, iOS, Android, React Native, and Flutter, with every configuration parameter and event.
- [Employment Data](https://docs.atomicfi.com/reference/employment-data.md): The raw and derived employment, income, and identity fields Atomic delivers through webhooks.
- [UserLink API Reference](https://docs.atomicfi.com/reference/api.md): Authentication, access tokens, tasks, users, companies, and every UserLink REST endpoint with request and response schemas.
- [Webhook Reference](https://docs.atomicfi.com/reference/webhooks.md): Every UserLink webhook event with its payload, including task status changes and employment data delivery.

## UserLink Plugins

- [Banno Onboarding Guide](https://docs.atomicfi.com/plugins/banno.md): Set up Atomic inside the Banno digital banking platform.
- [Uplink Handoff](https://docs.atomicfi.com/plugins/uplink-handoff.md): Run your own automation in the authenticated session Transact creates after the user signs in.

## PayLink Products

- [Switch - Plan Your UX](https://docs.atomicfi.com/products/switch/plan-your-ux.md): Design the screens around a payment method switch at merchants and subscription services.
- [Switch Implementation Guide](https://docs.atomicfi.com/products/switch/implementation.md): Launch Transact to update the payment method on file at a merchant and confirm the result.
- [Manage - Plan Your UX](https://docs.atomicfi.com/products/manage/plan-your-ux.md): Design the screens for linking bills and presenting account, plan, and action data.
- [Manage Implementation Guide](https://docs.atomicfi.com/products/manage/implementation.md): Connect accounts, ingest bill and plan data, and execute actions such as cancel and pause.
- [Payments Hub Integration Guide](https://docs.atomicfi.com/products/manage/payments-hub.md): Atomic's bundled UI for PayLink Manage: one place for users to view connected accounts and take actions.

## PayLink Product Guides

- [Connect Accounts](https://docs.atomicfi.com/paylink/guides/connect-accounts.md): Start a Transact session so a user can sign in to a merchant and link the account.
- [Ingest Data](https://docs.atomicfi.com/paylink/guides/ingest-data.md): Receive connected account data through webhooks or retrieve it on demand from the API.
- [Plaid Processor Token](https://docs.atomicfi.com/guides/plaid-processor-token.md): Share transaction history with Atomic through a Plaid processor token instead of sending it directly.
- [Order Monitoring](https://docs.atomicfi.com/paylink/guides/order-monitoring.md): Pull e-commerce order data from merchants such as Amazon to enrich bank transactions.
- [Executing Actions](https://docs.atomicfi.com/paylink/guides/execute-actions.md): Cancel, pause, or change a plan, and refresh data, through actions on a connected account.

## PayLink Advanced Guides

- [Single Switch](https://docs.atomicfi.com/paylink/guides/single-switch.md): Launch Transact with the merchant and payment method already chosen.
- [Just-In-Time (JIT) Flow](https://docs.atomicfi.com/paylink/guides/jit-flow.md): Send card data to Atomic only when the task needs it, through the onDataRequest handler.
- [Company Search](https://docs.atomicfi.com/guides/company-search.md): Call the Company Search endpoint from your backend to build an employer picker and interpret the results.
- [Card Data Environment (CDE) Bypass](https://docs.atomicfi.com/paylink/guides/cde-bypass.md): Send card data from the user's device to the merchant without it passing through Atomic's Card Data Environment.

## PayLink AI Agents

- [Cancel Subscriptions from an AI Agent](https://docs.atomicfi.com/paylink/guides/ai-agent-cancel.md): Build an AI agent that helps users cancel subscriptions with the Atomic API and Transact SDK. Follow the backend tools, native Transact handoff, and webhook results in an example app.
- [Agent Tool Definitions](https://docs.atomicfi.com/paylink/reference/agent-tools.md): Download the subscription agent tool definitions and review the available tools and version metadata.
- [tools.json](https://docs.atomicfi.com/agent-tools/subscriptions/tools.json): Tool definitions to register with your model.
- [README.md](https://docs.atomicfi.com/agent-tools/subscriptions/README.md): Definition format, source revision, and refresh procedure.

## PayLink Reference

- [Glossary](https://docs.atomicfi.com/paylink/reference/glossary.md): Definitions of company, account, bill, plan, order, suggestion, task, web view, and each action type.
- [PayLink Transact SDK Reference](https://docs.atomicfi.com/paylink/reference/transact-sdk.md): Install and initialize Transact for PayLink on iOS, Android, React Native, Flutter, and Capacitor, with every configuration parameter and event.
- [PayLink API Reference](https://docs.atomicfi.com/paylink/reference/api.md): Authentication, access tokens, tasks, accounts, bills, actions, and every PayLink REST endpoint with request and response schemas.
- [PayLink Webhook Reference](https://docs.atomicfi.com/paylink/reference/webhooks.md): Every PayLink webhook event with its payload, including task status changes and account data updates.

## Optional

- [Full documentation text](https://docs.atomicfi.com/llms-full.txt): Every page above in one file. Use it when the page links are not enough.