How to Use Claude Opus 5 for Free ?

Anthropic launched Claude Opus 5 on July 24, 2026. The answer to “Can I use it for free?” depends on where you use it: in Claude apps, Opus 5 is available through paid subscriptions; through the API, there is no unlimited free access to claude-opus-5. API trial and promotional credits can help you test an integration, but they are finite.

Try Apidog today

Opus 5 costs $5 per million input tokens and $25 per million output tokens at standard API rates—the same as Opus 4.8 and half of Fable 5’s $10 / $50 pricing. You can reduce that bill substantially with Batch API requests, prompt caching, and lower effort settings. Use Apidog to send, save, compare, and inspect those API requests.

For the full specification, see what is Claude Opus 5. Anthropic’s Opus 5 launch post covers the announcement, while the models overview lists model IDs and availability.

Keep this distinction in mind:

• Claude app access: covered by a paid subscription, subject to usage limits.
• API access: paid per token after any trial or promotional credits are exhausted.

Free path 1: Claude subscription tiers

Anthropic’s launch materials identify two consumer subscription tiers for Opus 5:

• Max: Opus 5 is the default model.
• Pro: Opus 5 is the highest-performing model available on the plan.

The launch materials do not explicitly list the free Claude plan as an Opus 5 surface. Check the model picker in your account before relying on free-plan availability.

Opus 5 is also available through Claude Code, Claude Cowork, and GitHub Copilot. If you already have a paid subscription, you may already have access—but usage is metered.

Be aware that Opus 5 can consume allowances faster than Opus 4.8:

• Thinking is enabled by default.
• Responses can be longer.
• The model delegates to subagents more readily.

For implementation guidance, see how to use Claude Opus 5 in Claude Code and how to use Claude Opus 4.8 for free.

Free path 2: API trial and cloud promotional credits

The Claude API model ID is:

claude-opus-5

The API is pay-as-you-go, but two legitimate options can let you test it without paying upfront:

• New Anthropic API account credits: New accounts typically start with a small credit balance. Use it to verify your integration and measure token consumption before attaching a payment method.
• Cloud platform promotional credits: Opus 5 is available through Amazon Bedrock as anthropic.claude-opus-5, Claude Platform on AWS, Google Cloud, and Microsoft Foundry. New cloud accounts may include promotional credits that can be used for Claude usage.

Promotional terms and amounts change frequently. Check each platform’s current offer directly.

Use credits for measurement rather than production traffic:

1. Run representative prompts.
2. Record the usage block from every response.
3. Calculate input, output, and cached-token costs per task.
4. Scale only after you understand the real cost profile.

See Anthropic’s pricing documentation for current rates.

Watch default thinking costs

On Opus 5, thinking is enabled by default. On Opus 4.8, requests without a thinking field ran without thinking. On Opus 5, the same request uses adaptive thinking.

Thinking tokens are billed as output tokens at $25 per million tokens. If you migrate an existing Opus 4.8 test suite unchanged, it may consume trial credits more quickly.

See migrating from Opus 4.8 to Opus 5 for migration-specific pitfalls.

There is no free unlimited API path

There is no free Claude API tier with unlimited claude-opus-5 calls.

Avoid proxies, shared key pools, and resellers that claim to provide free frontier-model access. These arrangements can violate Anthropic’s terms, be revoked without notice, and send your prompts through infrastructure you do not control.

After trial or promotional credits are gone, you either pay per token or stop making API calls.

The cheapest paid path

The standard Opus 5 API rate is:

Token type	Cost per million tokens
Input	$5.00
Output	$25.00

Use the following levers to lower costs.

Lever 1: Use the Batch API for asynchronous work

The Batch API costs 50% less than standard API calls:

Token type	Standard API	Batch API
Input	$5.00 / MTok	$2.50 / MTok
Output	$25.00 / MTok	$12.50 / MTok

Use Batch API for workloads that do not need an immediate response:

• Nightly evaluations
• Bulk document processing
• Classification backfills
• Regression test suites
• Content pipelines

Batch requests use the same model and produce the same quality. The tradeoff is asynchronous processing and additional latency.

Batch also supports up to 300,000 output tokens per request with the output-300k-2026-03-24 beta header, compared with 128,000 tokens on the standard Messages API.

Fast mode is not available with the Batch API.

Lever 2: Set output_config.effort deliberately

Opus 5 exposes an output_config.effort setting:

{
  "output_config": {
    "effort": "low"
  }
}

It defaults to high. Lower effort generally means fewer thinking tokens, which directly reduces output-token spending.

Test at least these settings against your own evaluation set:

low
medium
high

Anthropic states that low and medium are stronger on Opus 5 than equivalent settings on prior Opus models. Do not assume settings carried over from Opus 4.8 have the same quality/cost tradeoff.

Two implementation details matter:

• Effort affects thinking, not response length. If you need shorter visible answers, specify a limit in the prompt.
• Do not disable thinking as a cost-control strategy. Combining thinking: {"type": "disabled"} with xhigh or max effort returns a 400 error. Anthropic recommends keeping thinking enabled and lowering effort instead.

For the full configuration breakdown, see Claude Opus 5’s effort parameter.

Lever 3: Add prompt caching for stable context

Cached input tokens cost $0.50 per million tokens, compared with $5.00 per million standard input tokens.

Opus 5 supports cacheable prefixes starting at 512 tokens, down from 1,024 tokens on Opus 4.8. That makes caching viable for shorter reusable system prompts, policies, schemas, and reference documents.

Pricing:

Cache operation	Cost per million tokens
Cache hit	$0.50
5-minute cache write	$6.25
1-hour cache write	$10.00

For example, consider a request with:

• 40,000 tokens of stable context
• 10,000 tokens of variable user input

Without caching:

50,000 × $5 / 1,000,000 = $0.25 input cost

With a 5-minute cache:

Initial cache write:
40,000 × $6.25 / 1,000,000 = $0.25

Variable input:
10,000 × $5 / 1,000,000 = $0.05

Subsequent requests cost:

Cached prefix:
40,000 × $0.50 / 1,000,000 = $0.02

Fresh input:
10,000 × $5 / 1,000,000 = $0.05

Total input cost per cache hit = $0.07

Confirm caching is working by checking this field in the API response:

{
  "usage": {
    "cache_read_input_tokens": 40000
  }
}

If cache_read_input_tokens remains 0 on repeated requests, review your cache breakpoint and ensure the reusable prefix is identical.

Lever 4: Skip fast mode unless latency is critical

Fast mode costs double the standard price:

Token type	Fast mode cost
Input	$10.00 / MTok
Output	$50.00 / MTok

It provides roughly 2.5× faster output speed, but it is a research preview, is available only through the first-party API, and cannot be used with Batch API.

Use it only for interactive workflows where users are waiting for output. Leave it off for cost-sensitive workloads.

Lever 5: Do not set inference_geo unless required

Setting this option adds a 10% multiplier across token categories:

{
  "inference_geo": "us"
}

Use it only when you have a data-residency requirement.

One small migration benefit: Opus 5’s tool-use system prompt overhead is 286 tokens when tool_choice is auto or none, compared with 290 tokens on Opus 4.8 and 675 tokens on Opus 4.7.

For broader cost optimization techniques, see cut your Claude API bill.

Cost comparison at a glance

Configuration	Input / MTok	Output / MTok	Best for
Standard, effort high	$5.00	$25.00	Interactive default
Batch API	$2.50	$12.50	Asynchronous workloads
Cache hits on a stable prefix	$0.50	n/a	Repeated long-context calls
Fast mode	$10.00	$50.00	Latency-critical workflows only
inference_geo: "us"	1.1× all categories	1.1× all categories	Data residency requirements

The 50% Batch API discount applies to standard token pricing. Verify how Batch and cached-token pricing interact on your own invoice before modeling combined savings.

See Claude Opus 5 pricing for worked examples.

Test the cheap paths in Apidog

Every cost lever above is measurable from the API response. Start with a baseline request:

curl https://api.anthropic.com/v1/messages \
  --header "x-api-key: $ANTHROPIC_API_KEY" \
  --header "anthropic-version: 2023-06-01" \
  --header "content-type: application/json" \
  --data '{
    "model": "claude-opus-5",
    "max_tokens": 4096,
    "output_config": {"effort": "low"},
    "messages": [
      {"role": "user", "content": "Summarize this OpenAPI spec in three sentences."}
    ]
  }'

In Apidog, save this as a POST request and store ANTHROPIC_API_KEY in an environment variable. Do not paste API keys directly into request bodies or commit them to source control.

Then run these checks:

1. Compare effort levels
   
   Duplicate the request and test low, medium, and high. Compare usage.output_tokens and quality results.

2. Verify cache hits
   
   Send the same long-prefix request twice. On the second request, confirm that usage.cache_read_input_tokens is non-zero.

3. Detect max_tokens truncation
   
   Thinking and visible output share the max_tokens budget. Add an assertion that fails when:
   

   {
     "stop_reason": "max_tokens"
   }

This indicates you may have paid for thinking or partial output without receiving a complete usable answer.

1. Inspect streams and tool calls Review SSE responses and tool-call payloads when debugging expensive agent loops. Unexpected tool retries or long reasoning paths can increase output-token spending.

Download Apidog to follow along. For a complete integration walkthrough, see how to use the Claude Opus 5 API.

Is Opus 5 the right model to optimize?

Sometimes the lowest-cost option is a different model.

Sonnet 5 has introductory pricing of $2 / $10 per million input/output tokens, increasing to $3 / $15 on September 1, 2026. It also supports the same 1 million token context window.

If your workload does not require agentic coding or complex multi-step reasoning, benchmark Sonnet 5 before optimizing an Opus 5 deployment.

See:

• Claude Opus 5 vs Sonnet 5
• how to use Claude Sonnet 5 for free

Anthropic claims that Opus 5 delivers more than double Opus 4.8’s Frontier-Bench score, is within 0.5% of Fable 5 on CursorBench 3.2 at half the price, and outperforms Fable 5 on OSWorld 2.0 at one-third of the cost. These are vendor-published figures and had not been independently reproduced as of July 25, 2026, so validate them against your workload.

Opus 5 is not the top of the Claude stack. Fable 5 remains Anthropic’s most capable widely released model, while Opus 5 trails Mythos 5 for cybersecurity exploitation and autonomous biology research. See what is Claude Fable 5 if your workload needs that higher capability ceiling.

Which path fits your use case?

Goal	Recommended path	Tradeoff
Chat, writing, research	Claude Pro or Max	Metered usage limits
Agentic coding	Claude Code on a paid plan	Long outputs and subagents consume allowance
Prototyping an integration	API trial or cloud promotional credits	Credits are finite
Cheapest production API	Batch API + caching + effort low	Batch adds latency; caching needs stable context
Cheapest interactive API	Standard API + caching + task-specific effort	No Batch discount

FAQ

Is Claude Opus 5 free?

Not through the API. In Claude apps, it is included with paid subscriptions: default for Max and the highest-performing model available to Pro. Anthropic’s launch materials do not explicitly name the free plan as an Opus 5 surface.

Can I get free Claude Opus 5 API access?

Only through finite new-account trial credits or promotional credits from Amazon Bedrock, Google Cloud, or Microsoft Foundry. There is no unlimited free API tier.

What is the cheapest legitimate way to run Opus 5 at volume?

Use Batch API pricing at $2.50 / $12.50 per million input/output tokens. Add prompt caching for stable prefixes over 512 tokens, use effort: "low" or medium where evaluations support it, leave fast mode off, and avoid inference_geo unless residency requirements demand it.

Should I disable thinking to save tokens?

No. Disabling thinking with xhigh or max effort returns a 400 error. Anthropic recommends leaving thinking enabled and reducing effort instead. Monitor the usage block in each response, and use a saved Apidog request with assertions to catch cost regressions.