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Backend Programming
Backend programming defines server-side behavior for ioLoop Projects through Cloud Flow and the supported Server API. Use it when a workflow requires trusted processing, protected business rules, database or file operations, integration calls, web hooks, supported background tasks, or AI Agent function behavior.
Unlike Page Flow, which runs in the visitor's browser, Cloud Flow runs on the server. It is the appropriate place for operations that must not depend on client-controlled values or expose private credentials.
Backend References
| Reference | Use It For |
|---|---|
| Cloud Flow Blocks | Find ioLoop-specific visual blocks for Database, files, connections, HTTP/web hooks, AI Agents, and other supported server-side workflows. |
| Server API | Look up functions available to supported backend code for data, files, integrations, system behavior, and other server-side operations. |
These are technical references. For creating, configuring, and managing Cloud Flow in the Project Editor, see Cloud Flow.
Cloud Flow
Cloud Flow is the server-side logic environment for a Project. It supports visual programming blocks and supported custom code for processing that belongs on the Backend.
Use Cloud Flow to implement behavior such as:
- Validating an operation against trusted business rules and permissions.
- Reading or changing Project Database records as permitted.
- Processing information received from a Page or Form.
- Calling external services through configured Integrations.
- Handling files and supported system operations.
- Receiving or processing web hook requests where configured.
- Running supported background workflows.
- Supporting AI Agent functions or other server-side actions.
For example, a registration Form can send a request to Cloud Flow, which checks capacity and authorization before creating a registration. The Form then displays the outcome returned by the server.
The Cloud Flow Blocks reference describes the available ioLoop-specific server-side blocks. It does not include standard Blockly blocks.
Server API
The Server API is the ioLoop API available to supported server-side code. It provides programmatic access to Backend capabilities and configured integrations.
The generated Server API reference includes areas such as:
| API Area | General Purpose |
|---|---|
$io.db | Supported Project Database operations. |
$io.fs | Supported file operations. |
$io.apicall | Supported external API interactions. |
$io.apikey | Supported API-key-related capabilities. |
$io.system | Supported server-side system operations. |
| Provider-specific API areas | Operations exposed for supported services such as Stripe, Square, and other integrations. |
The available functions and requirements depend on the specific API area and Project configuration. Refer to the individual function documentation for exact arguments, results, and supported behavior.
Cloud Flow Blocks vs. Server API
| Need | Recommended Starting Point |
|---|---|
| Assemble a server-side workflow visually | Cloud Flow Blocks |
| Use built-in blocks for data, files, or connections | Cloud Flow Blocks |
| Implement specialized server-side logic in code | Supported custom code and Server API |
| Find exact function parameters or return values | Server API |
| Learn where Cloud Flow is configured | Project Editor — Cloud Flow |
Use the visual blocks where they express the workflow clearly. Use supported code and APIs when more specialized processing is required.
Calling Backend Logic from the Frontend
Many Project workflows combine Page Flow and Cloud Flow:
- Page Flow collects input or responds to a Page event.
- It invokes Cloud Flow through a supported Project interface.
- Cloud Flow validates the request and performs the trusted operation.
- Cloud Flow returns the appropriate result.
- Page Flow updates the interface or shows an error.
The browser can propose input values and requested actions, but it must not be the sole source of authorization decisions. Cloud Flow should validate protected operations using trustworthy context and applicable Database permissions.
Background Tasks, Web Hooks, and Integrations
Some Backend workflows are initiated without an active Page interaction—for example, a configured web hook or supported background task. Others are invoked by Page Flow, an AI Agent, or an integration-related process.
The available trigger, scheduling, and execution behavior depends on the Cloud Flow configuration. Use the Cloud Flow documentation for setup and the Cloud Flow Blocks and Server API references for specific operations. Do not assume that all Backend workflows run automatically or that a given integration is available without configuration.
Choosing Your Next Reference
Use Cloud Flow Blocks while designing visual server workflows. Use Server API when writing supported backend code or checking function signatures.
For browser-side events, Form interactions, and UI updates, see Frontend Programming.