Together AI Security Basics

Overview

Together AI provides inference and fine-tuning for 100+ open-source models (Llama, Mixtral, Qwen, FLUX) via an OpenAI-compatible API. Security concerns include API key management for production inference, protecting fine-tuning datasets that may contain proprietary or sensitive data, rate limit handling to prevent cost overruns, and ensuring model outputs are not logged with sensitive prompt content. A leaked API key grants full access to inference, fine-tuning, and model management endpoints.

API Key Management

function createTogetherClient(): { apiKey: string; baseUrl: string } {
  const apiKey = process.env.TOGETHER_API_KEY;
  if (!apiKey) {
    throw new Error("Missing TOGETHER_API_KEY — store in secrets manager, never in code");
  }
  // Together keys access inference + fine-tuning — treat as production credentials
  console.log("Together AI client initialized (key suffix:", apiKey.slice(-4), ")");
  return { apiKey, baseUrl: "https://api.together.xyz/v1" };
}

Webhook Signature Verification

import crypto from "crypto";
import { Request, Response, NextFunction } from "express";

function verifyTogetherWebhook(req: Request, res: Response, next: NextFunction): void {
  const signature = req.headers["x-together-signature"] as string;
  const secret = process.env.TOGETHER_WEBHOOK_SECRET!;
  const expected = crypto.createHmac("sha256", secret).update(req.body).digest("hex");
  if (!signature || !crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected))) {
    res.status(401).send("Invalid signature");
    return;
  }
  next();
}

Input Validation

import { z } from "zod";

const InferenceRequestSchema = z.object({
  model: z.string().min(1).max(200),
  messages: z.array(z.object({
    role: z.enum(["system", "user", "assistant"]),
    content: z.string().max(100_000),
  })).min(1),
  max_tokens: z.number().int().min(1).max(4096).default(512),
  temperature: z.number().min(0).max(2).default(0.7),
  stop: z.array(z.string()).max(4).optional(),
});

function validateInferenceRequest(data: unknown) {
  return InferenceRequestSchema.parse(data);
}

Data Protection

const TOGETHER_SENSITIVE_FIELDS = ["api_key", "prompt_content", "fine_tune_dataset", "model_output", "system_prompt"];

function redactTogetherLog(record: Record<string, unknown>): Record<string, unknown> {
  const redacted = { ...record };
  for (const field of TOGETHER_SENSITIVE_FIELDS) {
    if (field in redacted) redacted[field] = "[REDACTED]";
  }
  return redacted;
}

Security Checklist

• [ ] API key stored in secrets manager, never in source code
• [ ] Separate keys for dev/staging/prod environments
• [ ] Fine-tuning datasets reviewed for sensitive content before upload
• [ ] Prompt content and model outputs never logged in plaintext
• [ ] Rate limit handling with exponential backoff to prevent cost overruns
• [ ] API key rotation scheduled quarterly
• [ ] Pre-commit hook blocks TOGETHERAPIKEY patterns
• [ ] Model access scoped to required models only

Error Handling

Resources

• Together AI Docs
• OWASP API Security Top 10

Next Steps

See together-prod-checklist.