The JSON specified for "Accounts_CustomFields" is invalid. T

Error message

The JSON specified for "Accounts_CustomFields" is invalid. The following error was thrown

What it means

A settings watcher builds MongoDB field projections for user data from the Accounts_CustomFields setting: it JSON.parses the value and maps each custom field into publicCustomFields/customCustomFields projections. On parse failure it only logs this warning and keeps the previously computed projections (empty on first run) — the visible symptom is custom fields silently missing from user data / REST API responses even though the raw setting still contains the invalid JSON.

Source

Thrown at apps/meteor/server/lib/users/getFullUserData.ts:68

	publicCustomFields = {};
	customFields = {};

	const value = settingValue?.trim();
	if (!value) {
		return;
	}

	try {
		const customFieldsOnServer = JSON.parse(value);
		Object.keys(customFieldsOnServer).forEach((key) => {
			const element = customFieldsOnServer[key];
			if (element.public) {
				publicCustomFields[`customFields.${key}`] = 1;
			}
			customFields[`customFields.${key}`] = 1;
		});
	} catch (e) {
		logger.warn({
			msg: 'The JSON specified for "Accounts_CustomFields" is invalid. The following error was thrown',
			err: e,
		});
	}
});

const getCustomFields = (canViewAllInfo: boolean): Record<string, 0 | 1> => (canViewAllInfo ? customFields : publicCustomFields);

const getFields = (canViewAllInfo: boolean): Record<string, 0 | 1> => ({
	...defaultFields,
	...(canViewAllInfo && fullFields),
	...getCustomFields(canViewAllInfo),
});

const findTargetUser = (type: string, value: string, opts: any) => {
	if (type === 'importId') return Users.findOneByImportId(value, opts);
	if (type === 'email') return Users.findOneByEmailAddress(value, opts);
	if (type === 'freeSwitchExtension') return Users.findOneByFreeSwitchExtension(value, opts);

View on GitHub (pinned to 2a7de45707)

Solutions

Fix the JSON in Accounts_CustomFields (validate with jsonlint) and save — the watcher recomputes projections immediately
Cross-check the server logs for the companion 'Invalid Custom Fields' warn from the API layer; both share the root cause
Prevent recurrence by validating the JSON in CI when deploying settings via env/infrastructure tooling

Defensive patterns

Strategy: validation

Validate before calling

function parseCustomFields(value: string): Record<string, { public?: boolean }> | null {
	try {
		return JSON.parse(value);
	} catch {
		return null;
	}
}
// null means: keep previous projections and alert the admin, do not silently drop fields

Try / catch

try {
	const customFieldsOnServer = JSON.parse(value);
	/* build projections */
} catch (e) {
	logger.warn({ msg: 'The JSON specified for "Accounts_CustomFields" is invalid. The following error was thrown', err: e });
	// projections stay at their previous state on purpose
}

Prevention

Validate Accounts_CustomFields JSON before saving, in the UI and in deployment pipelines
When custom fields vanish from API responses, check this warn first — it is the usual cause
Fix the value once; both the API watcher and this projection watcher recover together

When it happens

Trigger: Same root cause as the 'Invalid Custom Fields' warn from the API layer: Accounts_CustomFields saved as invalid JSON (trailing commas, single quotes, unquoted keys, truncated value). Fires whenever the watcher recomputes after such a save.

Common situations: Pasted JSON with syntax errors; env-deployed settings with mangled escaping; symptom noticed as customFields absent from users.info / full user data API responses.

Related errors

AI-assisted analysis of RocketChat/Rocket.Chat@2a7de45707 (2026-08-18). Data as JSON: /api/errors/0690ec51315b403c. Report an issue: GitHub.