What is the Claude Batch API?
The Claude Batch API is an asynchronous processing system that allows enterprises to submit large volumes of API requests — up to 10,000 in a single batch — for processing with a 24-hour SLA rather than real-time response. In exchange for this relaxed latency requirement, Anthropic charges 50% of standard API pricing: the most significant cost optimisation lever available to enterprise Claude deployments running high-volume workloads.
The trade-off is straightforward: if your use case doesn't require a response in the next 30 seconds, the Batch API cuts your AI processing costs in half. For many enterprise workflows — overnight document processing, bulk data extraction, large-scale content generation, periodic classification tasks — this is not a trade-off at all. The user never sees the API call in real-time regardless.
This article covers when to use the Batch API, how to implement it, and how to design systems that maximise cost savings while maintaining reliability for production workloads.
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The Batch API is the right choice for workloads where the response latency SLA is 24 hours or longer. In practice, this covers a surprisingly large share of enterprise Claude usage:
Document Processing Pipelines
Accounts payable teams receive invoices throughout the business day. Rather than processing each one in real-time as it arrives, queue them and submit a batch every 2–4 hours. The AP team works from a processed queue in the morning — invoices received by 6pm are extracted, validated, and ready for approval by 8am at half the cost. Same applies to contract review queues, compliance document analysis, and HR form processing.
Bulk Data Extraction
CRM enrichment, product catalogue processing, customer record standardisation — workloads where you have thousands of records to process and need structured output for each. These are ideal batch candidates: submit 5,000 records in one batch, retrieve clean JSON for all of them the next morning.
Content Generation at Scale
Product descriptions, personalised email drafts, report sections, marketing copy variants — any content generation task where you're producing hundreds or thousands of outputs can be batched. Generate overnight, review in the morning. E-commerce teams with large catalogues use this pattern to keep content fresh without real-time API costs.
Classification & Categorisation
Support ticket classification, document categorisation, sentiment analysis, content moderation — classification tasks are typically high-volume and tolerance for latency is high. Route incoming items to a classification queue, process in batches, update your system with results. Most support platforms have a natural overnight processing window where this works perfectly.
Research & Analysis Workloads
Competitive intelligence analysis, literature review processing, market research synthesis, regulatory monitoring — research tasks run as overnight jobs, with results available for the analyst team each morning. These are typically among the highest-token workloads, making the 50% cost saving particularly significant.
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Download Free →Implementation Guide
Implementing the Batch API requires a different architectural pattern than standard synchronous API calls. Here's the production pattern we deploy at client sites:
Step 1: Queue Design
Implement a persistent job queue (Redis, SQS, or even a database table works for lower volumes) where incoming items are stored with status pending. Your application writes to this queue as items arrive — invoices, documents, records to classify. A scheduler triggers the batch submission process at your defined intervals (every 2 hours, nightly at 11pm, etc.).
Step 2: Batch Submission
The batch submission process reads pending items from your queue, formats each as a standard API request object with a unique custom_id (your internal reference), and submits the array to the Batches endpoint. Store the returned batch_id and update queue items to submitted status.
Step 3: Status Polling
Implement a polling worker that checks batch status every 15–30 minutes using the batch id. When status returns ended, the batch is complete. For time-sensitive batches, increase polling frequency in the final hour of the expected processing window.
Step 4: Result Retrieval & Processing
Retrieve results from the batch results endpoint — this returns a JSONL file with one result per line, keyed by your custom_id. Process each result: update your database, trigger downstream workflows, and move items to completed or failed status in your queue. Failed items should be automatically requeued for the next batch cycle unless they represent permanent errors (invalid format, content policy).
Step 5: Monitoring & Alerting
Track batch completion time, per-item success rates, error distributions, and cost per item. Alert if a batch hasn't completed within 20 hours (giving time to investigate before the SLA window closes). Track which item types generate the most errors — these are candidates for prompt refinement.
Cost Optimisation Strategy
The 50% Batch API discount is the baseline. Layer these additional optimisations for maximum cost efficiency:
Combine with Prompt Caching
Prompt caching allows reuse of identical prompt prefixes across requests in a batch. If your system prompt is 2,000 tokens and appears in 5,000 requests, prompt caching eliminates 10M tokens of input processing — at standard prices, this alone can save as much as the Batch API discount. For large system prompts with consistent content, the combination of Batch API + prompt caching can reduce effective costs by 70–80% vs. standard real-time API.
Right-Size Model Selection
Not all batch tasks need Claude Sonnet. Classification, routing, and extraction of simple structured documents can often be handled by Claude Haiku at 1/5th the cost. Reserve Sonnet for tasks requiring genuine reasoning, complex analysis, or nuanced writing. Build a routing layer that assigns each request to the appropriate model based on complexity and output requirements.
Optimise Prompt Length
In batch processing, every token is multiplied by the batch size. A 500-token reduction in your system prompt saves 500 × batch_size tokens per batch. Audit your prompts for unnecessary verbosity, repeated instructions, and over-specified output schemas. Tighter prompts not only cost less but often perform better.
Error Handling & Reliability
Production batch processing requires robust error handling at multiple levels:
- Item-level errors: Always handle per-item failures independently. A single malformed request should not block the rest of the batch. Implement item-level retry logic with exponential backoff for transient errors.
- Batch-level failures: If an entire batch fails (rare, but possible), implement automatic resubmission with the same items. Limit resubmission attempts to 3 to prevent infinite loops.
- Content policy rejections: Some items may be rejected for content policy reasons. These are permanent failures — do not retry. Log, alert, and review. Implement pre-screening with a fast classification pass if content quality is variable.
- Timeout handling: If a batch hasn't completed after 23 hours, cancel it, requeue the items, and submit a new batch immediately. Always design for the possibility that a batch doesn't complete within SLA.
- Partial results: The Batch API may return results even if some items fail. Always process successful results from partially completed batches rather than discarding the entire batch output.
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