marmelab/react-admin · error · Error

ra.notification.data_provider_error

ra.notification.data_provider_error

Error message

ra.notification.data_provider_error

What it means

validateResponseFormat checks that a custom dataProvider returns a well-formed response. When the dataProvider returns null/undefined for a query type, react-admin logs the details to console.error and throws this generic error, which surfaces as a data_provider_error notification because the real problem is the provider's contract violation.

Source

Thrown at packages/ra-core/src/dataProvider/validateResponseFormat.ts:11

import {
    fetchActionsWithRecordResponse,
    fetchActionsWithArrayOfIdentifiedRecordsResponse,
    fetchActionsWithArrayOfRecordsResponse,
    fetchActionsWithTotalResponse,
} from './dataFetchActions';

function validateResponseFormat(response, type, logger = console.error) {
    if (!response) {
        logger(`The dataProvider returned an empty response for '${type}'.`);
        throw new Error('ra.notification.data_provider_error');
    }
    if (!response.hasOwnProperty('data')) {
        logger(
            `The response to '${type}' must be like { data: ... }, but the received response does not have a 'data' key. The dataProvider is probably wrong for '${type}'.`
        );
        throw new Error('ra.notification.data_provider_error');
    }
    if (
        fetchActionsWithArrayOfRecordsResponse.includes(type) &&
        !Array.isArray(response.data)
    ) {
        logger(
            `The response to '${type}' must be like { data : [...] }, but the received data is not an array. The dataProvider is probably wrong for '${type}'`
        );
        throw new Error('ra.notification.data_provider_error');
    }
    if (
        fetchActionsWithArrayOfIdentifiedRecordsResponse.includes(type) &&

View on GitHub (pinned to 051f511bb0)

Solutions

1. Ensure every dataProvider method returns a promise resolving to an object: return fetch(...).then(...).
2. Check the console — the logger prints 'The dataProvider returned an empty response for <type>' pinpointing the verb.
3. Add return before async calls in each case branch of the provider.
4. Wrap the provider with a debug proxy logging each call and its result.

Example fix

// before
const dataProvider = {
  getList: (resource, params) => { fetch(url).then(r => r.json()); }, // no return
};
// after
const dataProvider = {
  getList: (resource, params) => fetch(url).then(r => r.json()).then(json => ({ data: json, total: json.length })),
};

const result = await myDataProvider.getList('posts', params);
if (!result || typeof result !== 'object') throw new Error('dataProvider returned empty response');

const isValidResponse = (r: unknown): r is { data: unknown } =>
    r != null && typeof r === 'object' && 'data' in r;

try {
    await dataProvider.getList('posts', params);
} catch (e) {
    if (e.message === 'ra.notification.data_provider_error') {
        console.error('dataProvider returned an empty response — check every verb has a return');
    }
}

When it happens

Trigger: A custom dataProvider method returns nothing (missing return statement) or an async function resolves to undefined; a wrapped provider forgets to return for one verb (e.g. deleteMany).

Common situations: Hand-written dataProviders where a switch statement branch lacks a return; providers that fire-and-forget fetch calls; interceptors/middleware that swallow the response.

Related errors

• Found getManyReference result in cache without total or page
• Missing dataProvider prop. React-admin requires a valid data
• useCanAccess must be used inside a <Resource> component or p
• useCreateController requires a non-empty resource prop or co
• useEditController requires a non-empty resource prop or cont

AI-assisted analysis of marmelab/react-admin@051f511bb0 (2026-08-30). Data as JSON: /api/errors/078eb68a68a2ef6a. Report an issue: GitHub.