together-common-errors

Together AI Common Errors

Overview

Together AI provides OpenAI-compatible inference, fine-tuning, and batch processing across 100+ open-source models (Llama, Mixtral, Qwen, FLUX). Common errors include model-not-available failures when requesting deprecated or gated models, token limit violations that differ per model architecture, and fine-tune job failures from dataset formatting issues. The API is compatible with any OpenAI client library at base_url = 'https://api.together.xyz/v1'. Model IDs use the full namespace format (e.g., meta-llama/Meta-Llama-3.1-8B-Instruct) and must match exactly. This reference covers inference, fine-tuning, and deployment errors.

Error Reference

Code	Message	Cause	Fix
401	Unauthorized	Invalid or missing TOGETHER_API_KEY	Verify key at api.together.xyz > Settings
400	Model not found	Wrong model ID or model deprecated	Use client.models.list() to get valid model IDs
400	Token limit exceeded	Input + max_tokens exceeds model context	Reduce input length or lower max_tokens parameter
400	Invalid fine-tune dataset	JSONL format errors or missing required fields	Each line must be valid JSON with messages array
402	Insufficient credits	Account balance depleted	Add credits at api.together.xyz > Billing
404	Fine-tune job not found	Invalid job ID or job expired	List active jobs with client.fine_tuning.list()
429	Rate limit exceeded	Too many concurrent requests	Implement backoff; use batch API for 50% cost reduction
500	Model overloaded	High demand on specific model	Retry with backoff; try alternative model of same family

Error Handler

interface TogetherError {
  code: number;
  message: string;
  category: "auth" | "rate_limit" | "validation" | "billing";
}

function classifyTogetherError(status: number, body: string): TogetherError {
  if (status === 401) {
    return { code: 401, message: body, category: "auth" };
  }
  if (status === 402) {
    return { code: 402, message: body, category: "billing" };
  }
  if (status === 429) {
    return { code: 429, message: "Rate limit exceeded", category: "rate_limit" };
  }
  return { code: status, message: body, category: "validation" };
}

Debugging Guide

Authentication Errors

Together uses Bearer token authentication. Pass TOGETHER_API_KEY via Authorization: Bearer header or set it in the client constructor. Keys do not expire but can be revoked. If using the OpenAI client library, set base_url='https://api.together.xyz/v1' and pass the Together key as api_key.

Rate Limit Errors

Rate limits vary by plan tier and are enforced per-key. Free tier allows 5 requests/second; paid tiers scale higher. Use the batch inference API (/v1/batch) for non-real-time workloads at 50% cost reduction. Check X-RateLimit-Remaining header to monitor quota.

Validation Errors

Model IDs must match exactly (e.g., meta-llama/Meta-Llama-3.1-8B-Instruct). Use client.models.list() to enumerate available models. Token limits vary per model -- Llama 3.1 supports 128K context while older models may support only 4K. Fine-tune datasets must be JSONL with each line containing a messages array in chat format. Empty messages arrays or missing role fields cause silent validation failures. Validate each JSONL line independently before uploading.

Error Handling

Scenario	Pattern	Recovery
Model deprecated	400 with "not found"	Check model list; migrate to successor model
Token limit exceeded	400 on long prompts	Truncate input or use model with larger context window
Fine-tune dataset rejected	JSONL validation errors	Validate each line independently; fix and re-upload
Credits depleted mid-batch	402 after N successful calls	Add credits, resume from last successful request
Model overloaded at peak	500 on popular models	Fall back to alternative model in same family

Quick Diagnostic

# Verify API connectivity and list available models
curl -s -o /dev/null -w "%{http_code}" \
  -H "Authorization: Bearer $TOGETHER_API_KEY" \
  https://api.together.xyz/v1/models

Resources

• Together AI Documentation
• API Reference
• Supported Models

Next Steps

See together-debug-bundle.