OpenAI API alternatives: model APIs developers switch to

Teams look for OpenAI API alternatives, either to replace OpenAI or to add a second provider, for four reasons: price per token, rate limits, a model that does one job better, or a data rule. This page lists seven alternatives with the per-million-token prices each provider publishes as of October 2026, and what it takes to switch your code. If you are a chat user rather than a developer, you want ChatGPT alternatives instead.

How the picks were chosen

Each pick is a hosted API you can call today with a key and pay for by usage. We kept providers that publish token prices on a public page, offer a general-purpose text model, and document how to call them from existing code. Prices are standard (non-batch) rates for short prompts unless noted. We did not benchmark output quality; per-token price says nothing about how many tokens a model needs for your task.

For reference, OpenAI's own pricing page lists gpt-6.1-sol at $2.00 input and $10.00 output per million tokens, gpt-6-luna at $0.10 and $0.50, and gpt-6-astra at $10.00 and $50.00. Batch and Flex processing cost half.

Price comparison per million tokens

One caution before comparing rows. Anthropic notes that Claude 4.7 and later models use a newer tokenizer that produces about 30% more tokens for the same text, so equal per-token prices do not mean equal cost per request. Run a sample of your real prompts through each candidate and compare the bill.

1. Anthropic (Claude API)

Best for: long-context work, coding agents, document tasks · Price: from $1 input / $5 output per 1M tokens (Haiku 4.5, as of Oct 2026) · Free plan: not listed on the pricing page

Anthropic's API offers four current models: Fable 5.1 ($10 / $50), Opus 5.5 ($4 / $20), Sonnet 5.5 ($2 / $10) and Haiku 4.5 ($1 / $5). Prompt caching cuts the cost of repeated context: cache hits on Opus 5.5 and Sonnet 5.5 cost $0.20 per million tokens. If you need inference kept in the US, the inference_geo setting adds a 1.1x multiplier on Claude 4.6 and later models.

Switching: Anthropic provides an OpenAI SDK compatibility layer, but its docs say it is meant for testing and comparing models and is not considered production-ready for most uses. Features such as PDF processing, citations, extended thinking and prompt caching need the native Claude API. To choose between the two main models, see Claude Opus vs Sonnet.

2. Google (Gemini API)

Best for: a real free tier and cheap fast models · Price: Gemini 3.8 Flash $0.75 input / $3.75 output per 1M tokens through Dec 31, 2026 · Free plan: yes

The Gemini API has a free tier with free input and output tokens on Flash models, and a paid tier with higher rate limits, context caching and a Batch API at 50% off. Gemini 3.8 Flash is priced at $0.75 / $3.75 until the end of 2026 and $1.50 / $7.50 from January 1, 2027. Gemini 3.5 Flash-Lite costs $0.30 / $2.50. Gemini 3.1 Pro Preview costs $2.00 / $12.00 for prompts up to 200k tokens and $4.00 / $18.00 above that, and has no free tier.

Switching: Google documents OpenAI library compatibility. You change the API key, the base URL and the model name, and keep the OpenAI SDK. Note the data rule: on the free tier, Google marks content as used to improve its products; on the paid tier it does not.

3. DeepSeek API

Best for: the lowest prices on a frontier-class model · Price: deepseek-flash $0.15 input / $0.60 output per 1M tokens off-peak, double at peak (as of Oct 2026) · Free plan: no, prepaid balance

DeepSeek runs two API models. deepseek-flash serves DeepSeek-V4.1-Flash, released September 10, 2026, with a 1M-token context and up to 384K output tokens. deepseek-v4-pro costs more. Off-peak rates are half the peak rates; peak hours are 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays, excluding Chinese public holidays. Cache hits cost $0.003 to $0.006 per million tokens on Flash.

Switching: the API accepts both the OpenAI and the Anthropic request formats at api.deepseek.com. The trade-off is data residency. DeepSeek's consumer privacy policy says data is stored in China; its API terms deserve a read before you send customer data. Full details are on our DeepSeek page.

4. Mistral API

Best for: open-weight models you can also self-host, plus batch discounts · Price: Mistral Small 4 $0.15 input / $0.60 output per 1M tokens; Medium 3.5 $1.50 / $7.50 (as of Oct 2026) · Free plan: yes, model testing in Studio

Mistral recommends Mistral Medium for most tasks and coding, and Mistral Small for cost-sensitive projects. Its pricing FAQ says batch processing cuts the price by 50% and cached input tokens cut input cost by up to 90%. Many models are open-weight: Mistral Small 4 and Mistral Large 3 are Apache 2.0, and Medium 3.5 is under a modified MIT license.

Price check: Mistral's API pricing page lists Mistral Large 3 at $0.50 input and $1.50 output, which is cheaper than Medium 3.5, so compare the model cards before assuming a bigger name costs more. Both Small 4 and Medium 3.5 have a 256k-token context.

5. xAI (Grok API)

Best for: a flagship model with cheap output tokens · Price: grok-4.7 $2.00 input / $6.00 output per 1M tokens (as of Oct 2026) · Free plan: not listed on the models page

xAI's docs describe grok-4.7 as its flagship for code and everything else, with configurable reasoning and a 500k-token context. Its knowledge cut-off is May 2026, and it has no access to current events unless you enable the Web Search or X Search tools. Output at $6 per million tokens is lower than most flagship models in the table.

Switching: the docs show examples that use the OpenAI SDK against the xAI endpoint. Note that logprobs are silently ignored on grok-4.20 and newer.

6. OpenRouter

Best for: trying many models through one key · Price: provider prices passed through; 5.5% platform fee on the Standard plan (as of Oct 2026) · Free plan: yes, 25+ free models at 50 requests a day

OpenRouter routes requests to other companies' models. It lists 500+ models from 80+ providers and says it passes through provider pricing with no markup on inference, charging its fee when you buy credits. The Standard pay-as-you-go plan adds auto-routing, budgets and spend controls, and prompt caching. The free plan gives 25+ free models with a limit of 50 requests a day.

Switching: OpenRouter implements the OpenAI API specification for its completions and chat completions endpoints, so most OpenAI client code works by changing the base URL and key. The cost is one more company in your data path.

7. Open-weight models you host yourself

Best for: strict data control or very high volume · Price: your own compute · Free plan: weights are free to download under their licenses

Several current models publish their weights. DeepSeek-V4.1-Flash and DeepSeek-V4-Pro are MIT-licensed on Hugging Face. Mistral Small 4 and Mistral Large 3 are Apache 2.0. Mistral notes that commercial deployments of some of its open-weight models require a Mistral license, so read the license for the exact model you plan to run.

The catch is operations. DeepSeek describes V4.1-Flash as a 552B-parameter mixture-of-experts model and invites teams planning a 2,000-GPU deployment to contact it. Plan for data-center hardware.

What switching involves

1. Pick two candidates from the table on price and context length.
2. Swap the base URL and key where the provider offers OpenAI compatibility (Google, DeepSeek, xAI, OpenRouter).
3. Re-test your prompts. System prompts tuned for one model often need edits for another. Our system prompt library and prompt engineering guide help here.
4. Check the features you rely on: structured output, tool calls, caching, batch, vision.
5. Compare real bills, since tokenizers differ.

I call the OpenAI API from [language] using model [current model].
Rewrite the client code below to call [new provider] through its OpenAI-compatible endpoint.
Keep these features working: [structured output / tool calls / streaming].
List anything the new provider does not support, and what I should change in my system prompt.

Code:
[paste your client code]

If the reason you are switching is a coding agent rather than an API, see the best AI coding tools.

FAQ

What is the cheapest OpenAI API alternative?

On published standard rates, Mistral Small 4 ($0.15 / $0.60) and DeepSeek's deepseek-flash at off-peak hours ($0.15 / $0.60) are the lowest in this list. OpenAI's own gpt-6-luna is cheaper still at $0.10 / $0.50.

Is there a free alternative to the OpenAI API?

Google's Gemini API has a free tier on Flash models, and OpenRouter offers 25+ free models at 50 requests a day. On Gemini's free tier, Google may use your content to improve its products.

Can I keep using the OpenAI SDK?

Yes for Google, DeepSeek, xAI and OpenRouter, which document OpenAI-compatible endpoints. Anthropic offers a compatibility layer for testing but recommends its native API for production.

Does OpenRouter charge more than going direct?

OpenRouter says it passes through provider token prices without markup and charges a fee when you buy credits, 5.5% on the Standard plan.