> For the complete documentation index, see [llms.txt](https://docs.coupler.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coupler.io/destinations/categories/api/json/common-issues.md).

# Common Issues

## Connection issues

<details>

<summary>404 Not Found when accessing the JSON URL</summary>

This is the most common issue with the JSON destination. The URL exists but returns a 404 error because the data flow has never completed a successful run.

**Fix:** Go back to your data flow in Coupler.io and click **Save and Run**. Wait for the run to complete successfully. Once at least one run has finished, the URL will return data.

{% hint style="danger" %}
Do not share or use the JSON URL in any downstream tool until the first successful run is complete. The 404 will persist until data has been written to the endpoint.
{% endhint %}

</details>

<details>

<summary>URL stops working or returns 404 after previously working</summary>

If the URL was working and then stopped, the access token may have been regenerated. This happens when someone clicks the **Update** button in the destination settings, which creates a new URL and invalidates the old one.

**Fix:** Open the data flow in Coupler.io, go to the destination settings, and copy the current URL. Update any tools or scripts that were using the old link.

</details>

<details>

<summary>JSON URL only works in the browser tab where it was downloaded (blob: URL)</summary>

Some browsers, particularly Firefox, generate a `blob:` URL when you click to download the file directly. This is a browser-specific behavior and the blob URL is only valid in that session.

**Fix:** Use the integration URL from Coupler.io directly (the `https://app.coupler.io/export/w/...` format), not a blob URL generated by your browser. Paste this URL into your target tool or HTTP client.

</details>

## Data issues

<details>

<summary>Nested or unflattened JSON objects from source data</summary>

Some sources (such as Pipedrive, Asana, or Shopify) return fields that contain nested JSON objects or arrays. These are passed through as-is and may not be flattened into simple key-value pairs.

**Fix:** Use Coupler.io's transformation options to reshape the data before it reaches the JSON destination. If a specific field needs flattening (for example, Asana custom fields or Shopify metafields), check whether the source connector supports a configuration option to expand those fields. If not, you may need to handle the transformation in the consuming tool.

{% hint style="warning" %}
Nested JSON fields are a known limitation for certain sources. If your use case requires flat data, consider using a spreadsheet destination like Google Sheets and consuming data from there instead.
{% endhint %}

</details>

<details>

<summary>Missing or empty columns in the JSON output</summary>

If a column appears empty in the JSON output, it may be that the source returned no value for that field during the last run, or new columns added after the first run are hidden by default in the preview.

**Fix:** Re-run the data flow and check the preview again. If the column is new, look for a toggle in the data preview to show hidden columns. If the field is genuinely empty from the source, verify the data exists in the source platform itself.

</details>

## Permission errors

<details>

<summary>Access token is invalid or expired</summary>

The JSON URL includes an access token as a query parameter. If this token has been invalidated (by clicking **Update** in destination settings), anyone using the old URL will receive an authentication error.

**Fix:** Retrieve the new URL from your data flow's destination settings and distribute it to any users or tools that need access. Treat the access token like a password — avoid sharing it publicly.

{% hint style="warning" %}
The access token in the JSON URL grants read access to your exported data. Do not post the full URL in public forums or issue trackers.
{% endhint %}

</details>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.coupler.io/destinations/categories/api/json/common-issues.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.