# Claude 4 Sonnet API Rate Limits, Pricing & Performance (July 2026)

- Tool: AI API Limits & Performance Matrix
- Last updated: July 2026

## TL;DR

The original Claude 4 Sonnet API string (claude-sonnet-4) stopped accepting requests on June 15, 2026. The active successor is Claude Sonnet 5 (claude-sonnet-5), released June 30, 2026, Anthropic's current default price/performance model. Start tier allows ~50 RPM; Scale tier reaches ~4,000 RPM / ~2M ITPM. Introductory pricing: $2.00 input / $10.00 output per MTok through August 31, 2026 — reverts to $3/$15 on September 1.

## Frequently asked questions

### Is claude-sonnet-4 still working?

No. The claude-sonnet-4 API string stopped accepting requests on June 15, 2026. Any calls using that model string will fail. Migrate to claude-sonnet-5, which is Anthropic's current default price/performance model released June 30, 2026.

### How do I increase Claude Sonnet 5 rate limits?

Rate limits increase automatically: ~$40 cumulative spend promotes you to Build; ~$200 cumulative unlocks Scale (~4,000 RPM / ~2M ITPM per third-party trackers). Above Scale, contact Anthropic sales for Custom tier with negotiated limits and no spend cap. Check your current tier at platform.claude.com/settings/limits or query GET /v1/rate-limits.

### Is the Claude Sonnet 5 API free?

No. There is no free tier. All token usage is billed from the Start tier. Introductory pricing is $2.00 input / $10.00 output per MTok through August 31, 2026, after which standard pricing ($3.00/$15.00) takes effect.

### How does Claude Sonnet 5 compare to Gemini 2.5 Pro pricing?

At intro rates, Sonnet 5 is $2.00 input / $10.00 output per MTok vs Gemini 2.5 Pro at $1.25 input (≤200K context) / $10.00 output. Gemini 2.5 Pro has a cheaper base input rate for short contexts, but Sonnet 5 has no long-context surcharge on its 1M window while Gemini charges 2× above 200K tokens. Cache reads: Gemini ~$0.125/MTok vs Sonnet 5 $0.20/MTok. Both offer 50% batch discounts.

### What does Claude API rate_limit_error mean?

rate_limit_error (HTTP 429) means you hit RPM, ITPM, or OTPM limits. Check anthropic-ratelimit-requests-remaining to see if it is RPM-bound; check anthropic-ratelimit-tokens-remaining for TPM. Read retry-after header for how many seconds to wait. For Sonnet 5, the most common cause is ITPM saturation from large contexts — activating prompt caching resolves this since cache reads are excluded from ITPM.

### Can Claude Sonnet 5 be used on Priority Tier?

No. Per Anthropic's service-tiers documentation (July 2026), Claude Sonnet 5 is NOT supported on Priority Tier. This is a per-model restriction that applies at all tiers including Custom. If Priority Tier access is required for your use case, use Claude Opus 4.8 instead.

### When does Claude Sonnet 5 introductory pricing end?

Introductory pricing ($2.00/$10.00 per MTok) ends August 31, 2026. Starting September 1, 2026, standard pricing applies at $3.00 input / $15.00 output per MTok. Batch API pricing adjusts proportionally. This is a high-urgency deadline — schedule bulk workloads before August 31.

### How can I reduce Claude API costs for a multi-team organization using Sonnet 5?

Top approaches: (1) Prompt caching — $0.20/MTok cache reads excluded from ITPM; (2) Batch API — $1.00/$5.00 at intro rates (50% off); (3) Partition API keys by team to monitor pool usage; (4) Query GET /v1/rate-limits to track remaining headroom per dimension; (5) Route classification and routing tasks to Haiku 4.5 ($1/$5) and reserve Sonnet 5 for generation. RapidDev helps teams implement multi-model routing and quota engineering — book a free scoping call at rapidevelopers.com/contact.

### What is the difference between Claude 4 Sonnet and Claude Sonnet 5?

Claude 4 Sonnet (claude-sonnet-4) was the earlier snapshot in the Sonnet 4.x series that stopped serving on June 15, 2026. Claude Sonnet 5 (claude-sonnet-5), released June 30, 2026, is the current GA model and Anthropic's default recommendation. They are in the same Sonnet 4.x/5 org-level pool and carry the same tier limits. Use claude-sonnet-5 for all new work.

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Source: https://www.rapidevelopers.com/ai-api-limits-performance-matrix/claude-4-sonnet
© RapidDev — https://www.rapidevelopers.com/ai-api-limits-performance-matrix/claude-4-sonnet