PriceIndex

AI model capabilities

AI models that support JSON mode

Find models with a listed response-format option and compare their token costs. Compare 280 supporting models by input price, output price, context window and published intelligence. Find the cheapest option for a reference text workload, then check the serving API before you build.

280 supporting models30 AI providersUSD · prices per 1M tokens

Lowest reference cost

Llama 3.1 8B Instruct

$0.03

1M input + 250K output tokens. Tool fees and discounts excluded.

Highest published intelligence

Claude Opus 5.5

57.6 AA Intelligence Index

Among supporting models with a published score; not a capability-specific benchmark.

Cheapest AI models with JSON mode

Ranked by the cost of 1 million input and 250,000 output tokens at standard rates. A different token mix can change the cheapest model. Support requires an explicitly listed catalog feature, not an inference from a model family.

GLM 5.3 FlashZ.ai
Input /1M
$0.03
Output /1M
$0.08
Reference cost
$0.05
Context
1M
AA Intelligence
41.8
gpt-oss-20bOpenAI
Input /1M
$0.03
Output /1M
$0.13
Reference cost
$0.06
Context
131K
AA Intelligence
9
Qwen3.7 FlashQwen
Input /1M
$0.03
Output /1M
$0.13
Reference cost
$0.06
Context
1M
AA Intelligence
—
Gemma 3 4BGoogle
Input /1M
$0.05
Output /1M
$0.10
Reference cost
$0.08
Context
131K
AA Intelligence
4.8
Gemma 3 12BGoogle
Input /1M
$0.05
Output /1M
$0.15
Reference cost
$0.09
Context
131K
AA Intelligence
3.8
Solar Mini 4Upstage
Input /1M
$0.05
Output /1M
$0.20
Reference cost
$0.10
Context
524K
AA Intelligence
—

Showing 15 of 280

280 matching models · Missing intelligence scores are shown as —.

What is json mode?

JSON mode uses an API response-format option to request machine-readable output. Valid JSON is not the same as matching a specific schema. Check the API documentation for supported formats and whether schema-constrained structured outputs are also available.

Before choosing a model

  • Confirm the selected API supports the JSON response format you need.
  • Validate required fields and types after parsing the response.
  • Handle incomplete responses and retry without assuming valid data.

Estimate your actual workload

Use your request volume and prompt and response sizes to compare monthly text-token costs. Add any search, external tool or provider-specific charges separately. Standard token prices do not assume cache hits or batch discounts.

LLM token cost calculator Pricing methodology

JSON mode FAQs

280 active models with positive input and output prices currently list JSON mode in the PriceIndex catalog. The table lists every match. A model is included only when its tracked feature data explicitly lists this capability; missing data is not treated as support.

Llama 3.1 8B Instruct has the lowest estimated text-token cost in this list for 1 million input tokens and 250,000 output tokens: $0.0300. A different input/output mix can change the ranking. This excludes tool fees, caching, discounts and taxes.

No. Capability availability can differ between serving APIs and model versions. Follow a model’s API documentation link and verify the exact version, endpoint and settings before choosing it.

We use standard USD input and output token prices: input price × 1 million tokens plus output price × 250,000 tokens, divided by 1 million. The directory excludes retired models, missing prices and zero-priced entries. Published AA Intelligence Index scores are shown when available and never estimated.

Confirm the selected API supports the JSON response format you need. Validate required fields and types after parsing the response. Handle incomplete responses and retry without assuming valid data.

Explore more AI capabilities