What causes "Multiple providers are set. Please set only one provider." in danny-avila/LibreChat?

Keep only one populated provider under speech.tts; empty or remove the rest.

Multiple providers are set. Please set only one provider.

Error message

Multiple providers are set. Please set only one provider.

What it means

getProvider filters ttsSchema entries (excluding `allowedAddresses`) for non-empty objects and requires exactly one. If two or more providers are populated (e.g. openai AND elevenlabs), it throws because it cannot pick.

Solutions

Keep only one populated provider under speech.tts; empty or remove the rest.
Reload the config / restart the API server.

Example fix

# before
speech:
  tts:
    openai: { apiKey: '...' }
    elevenlabs: { apiKey: '...' }

# after
speech:
  tts:
    elevenlabs: { apiKey: '...', voices: ['...'] }

Defensive patterns

Strategy: validation

Validate before calling

const providers = Object.entries(appConfig.speech.tts || {})
  .filter(([k, v]) => k !== 'allowedAddresses' && v && Object.keys(v).length > 0);
if (providers.length > 1) {
  throw new Error(`Multiple TTS providers configured: ${providers.map(p => p[0]).join(', ')}`);
}

Prevention

Keep exactly one TTS provider block populated.
Add a CI lint that fails when more than one TTS provider is non-empty.
Document the single-provider constraint by the speech.tts example.

When it happens

Trigger: librechat.yaml `speech.tts` has more than one provider block populated with at least one field each.

Common situations: Example config pasted with two providers; switched providers without removing the old block; default + override both populated.

Related errors

AI-assisted analysis of danny-avila/LibreChat@5ff282f900 (2026-08-12). Data as JSON: /api/errors/48118a6aed395764. Report an issue: GitHub.

Appendix: source

Thrown at api/server/services/Files/Audio/TTSService.js:60

  /**
   * Retrieves the configured TTS provider.
   * @param {AppConfig | null | undefined} [appConfig] - The app configuration object.
   * @returns {string} The name of the configured provider.
   * @throws {Error} If no provider is set or multiple providers are set.
   */
  getProvider(appConfig) {
    const ttsSchema = appConfig?.speech?.tts;
    if (!ttsSchema) {
      throw new Error(
        'No TTS schema is set. Did you configure TTS in the custom config (librechat.yaml)?',
      );
    }
    const providers = Object.entries(ttsSchema).filter(
      ([key, value]) => key !== 'allowedAddresses' && Object.keys(value).length > 0,
    );

    if (providers.length !== 1) {
      throw new Error(
        providers.length > 1
          ? 'Multiple providers are set. Please set only one provider.'
          : 'No provider is set. Please set a provider.',
      );
    }
    return providers[0][0];
  }

  /**
   * Selects a voice for TTS based on provider schema and request.
   * @async
   * @param {Object} providerSchema - The schema for the selected provider.
   * @param {string} requestVoice - The requested voice.
   * @returns {Promise<string>} The selected voice.
   */
  async getVoice(providerSchema, requestVoice) {
    const voices = providerSchema.voices.filter((voice) => voice && voice.toUpperCase() !== 'ALL');
    let voice = requestVoice;

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