Expert Guide

The Best Open-Source LLMs in 2026

Seven open-weight model families compared on license, context window and the per-million-token price where a vendor lists one, checked on 10 October 2026.

Product links may be affiliate links. How we rate 7 tools compared
TL;DR

Short answer: DeepSeek V4-Flash has the lowest paid API price of the seven, at $0.15 per million input tokens off-peak, and its weights are MIT-licensed. For MIT terms with a 1M-token context and a higher price, pick GLM-5.2 at $1.40 in and $4.40 out. For a model you run on your own servers under Apache 2.0, look at Qwen3.8-27B.

Three of the seven state a 1M-token context: DeepSeek V4, GLM-5.2 and Kimi K3. Output tokens cost three to six times the input rate wherever a vendor publishes both, so the output price matters more than the headline input rate. Read the license before you ship: MIT and Apache 2.0 are simple, and Kimi K3 uses its own license.

Key facts7 tools compared: DeepSeek V4, GLM-5.2 (Z.ai), Kimi K3 (Moonshot AI), Qwen3.8-27B (Alibaba)…
  • Updated: October 13, 2026
  • Top pick: DeepSeek V4 (best for: Teams that want the lowest paid API price among these models, with MIT weights to fall back on)
  • Top pick price as of October 13, 2026: DeepSeek V4: MIT weights; API $0.15 in, $0.60 out per 1M tokens (Flash, off-peak)
  • 7 tools compared: DeepSeek V4, GLM-5.2 (Z.ai), Kimi K3 (Moonshot AI), Qwen3.8-27B (Alibaba), gpt-oss-120b (OpenAI), Gemma 4 (Google), Mistral Small 4 (Mistral AI)
  • GLM-5.2 (Z.ai) (best for: Long, multi-step agent work where a 1M-token context and MIT terms matter more than price): MIT weights; API $1.40 in, $4.40 out per 1M tokens, $0.26 cached input
  • Kimi K3 (Moonshot AI) (best for: Teams with the hardware to serve a 2.8-trillion-parameter model and a 1M-token context): Own Kimi K3 License; API $3 in, $15 out per 1M tokens, $0.30 cached input
  • Qwen3.8-27B (Alibaba) (best for: Teams that want a multimodal model under Apache 2.0 that they can run on their own servers): Apache 2.0 weights; Alibaba Cloud API $0.50 in, $3 out per 1M tokens (International)

"Open-source" is loose here. Almost every model below is open-weight: you can download the parameters, but the training data stays private. The license decides whether you can build a paid product on the model, so this page lists it for each one.

We ranked the seven by what a buyer chooses on: price per token, license, context window, and how heavy the model is to run yourself.

Toolradar data: Toolradar tracks 42 AI model deployment tools as of October 2026, the software that serves a model on your own servers, and most of them have a free or open-source option.

Serving is the cost you carry when you self-host, so it belongs in the budget.

Toolradar profiles include Ollama, vLLM and OpenRouter, and the full list sits in the AI model deployment ranking.

How we ranked and checked: we read each vendor's own pricing page and each model card or license page on 10 October 2026.

Prices are USD per million tokens as the vendor lists them. We ran no benchmarks, so the order rests on price, license, context and size, not on scores. Where a vendor publishes no per-token price, the table says so.

Top Picks

Based on features, real-world fit, and value for money.

Best Open-Source LLMs in 2026: 7 tools compared, updated Oct 2026
ToolPricingBest for
DeepSeek V4MIT weights; API $0.15 in, $0.60 out per 1M tokens (Flash, off-peak)Teams that want the lowest paid API price among these models, with MIT weights to fall back on
GLM-5.2 (Z.ai)MIT weights; API $1.40 in, $4.40 out per 1M tokens, $0.26 cached inputLong, multi-step agent work where a 1M-token context and MIT terms matter more than price
Kimi K3 (Moonshot AI)Own Kimi K3 License; API $3 in, $15 out per 1M tokens, $0.30 cached inputTeams with the hardware to serve a 2.8-trillion-parameter model and a 1M-token context
Qwen3.8-27B (Alibaba)Apache 2.0 weights; Alibaba Cloud API $0.50 in, $3 out per 1M tokens (International)Teams that want a multimodal model under Apache 2.0 that they can run on their own servers
gpt-oss-120b (OpenAI)Apache 2.0 weights; no OpenAI API list price, so hosts set the rateTeams that want OpenAI-made open weights under Apache 2.0 and will host them themselves or through a provider
Gemma 4 (Google)Apache 2.0 weights; free on the Gemini API free tier, no paid rate listedSmall teams that want a 31B multimodal model under Apache 2.0 with a 256K context
Mistral Small 4 (Mistral AI)Apache 2.0 license; no per-token rate on Mistral's pricing pageTeams already on Mistral's API that want one model for instruct, reasoning and coding

Pricing read from each vendor's own published pricing page, checked Oct 2026. Every vendor here publishes a price.

Best for: Teams that want the lowest paid API price among these models, with MIT weights to fall back on

PricingMIT weights; API $0.15 in, $0.60 out per 1M tokens (Flash, off-peak)

+MIT weights: download, self-host and modify without a usage agreement
+Flash cache hits cost $0.003 per 1M input tokens, 50 times less than a miss
−Peak hours cost double: 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays
−V4-Pro takes no image input, while V4-Flash does
Visit DeepSeek V4 →

Best for: Long, multi-step agent work where a 1M-token context and MIT terms matter more than price

PricingMIT weights; API $1.40 in, $4.40 out per 1M tokens, $0.26 cached input

+MIT license and a 1M-token context, both stated on the model card
+Cached input at $0.26 per 1M tokens makes a long, repeated context cheaper to reuse
−Output at $4.40 per 1M is the second-highest output rate on this list
−Z.ai's pricing page now points API users to GLM-5.3 at the same rates, so name the exact model string in your code
Visit GLM-5.2 (Z.ai) →

Best for: Teams with the hardware to serve a 2.8-trillion-parameter model and a 1M-token context

PricingOwn Kimi K3 License; API $3 in, $15 out per 1M tokens, $0.30 cached input

+Native vision and a 1M-token context in an open-weight release
+Cached input at $0.30 per 1M is a tenth of the regular input rate
−The Kimi K3 License is custom, so read it before any commercial use
−At $15 per 1M output tokens it has the highest output price of the models that publish one
Visit Kimi K3 (Moonshot AI) →

Best for: Teams that want a multimodal model under Apache 2.0 that they can run on their own servers

PricingApache 2.0 weights; Alibaba Cloud API $0.50 in, $3 out per 1M tokens (International)

+Apache 2.0, with no separate usage agreement beyond the license
+Thinking and non-thinking modes carry the same $0.50 input rate
−At 27 billion parameters it is among the smallest models here, so test it on your hardest tasks before you commit
−The price is for Alibaba's International endpoint, billed in USD, and regional rates differ
Visit Qwen3.8-27B (Alibaba) →

Best for: Teams that want OpenAI-made open weights under Apache 2.0 and will host them themselves or through a provider

PricingApache 2.0 weights; no OpenAI API list price, so hosts set the rate

+Apache 2.0, which the model card describes as free of copyleft restrictions
+Only 5.1 billion parameters are active per token, so each answer is lighter to run than the total size suggests
−No OpenAI price to compare against, so a budget needs a host quote or a test run
−Hosting is on you: pay a provider or buy the GPUs yourself
Visit gpt-oss-120b (OpenAI) →

Best for: Small teams that want a 31B multimodal model under Apache 2.0 with a 256K context

PricingApache 2.0 weights; free on the Gemini API free tier, no paid rate listed

+Apache 2.0, the same permissive terms as gpt-oss-120b and Qwen3.8-27B
+Text, audio and image input in one open model
−The Gemini API lists it as free of charge with no paid tier, so paid use means self-hosting or a third-party host
−At 256K context it has less room than the three 1M-token models on this list
Visit Gemma 4 (Google) →

Best for: Teams already on Mistral's API that want one model for instruct, reasoning and coding

PricingApache 2.0 license; no per-token rate on Mistral's pricing page

+One model covers instruct, reasoning and coding
+Apache 2.0 license, as listed on Mistral's models overview page
−No published per-token price, so the monthly bill is unknown until a test run
−Mistral's pricing FAQ says commercial production use of its open-weight models can need a separate license
Visit Mistral Small 4 (Mistral AI) →

What it is

An open-weight LLM is a large language model whose trained parameters are published for download, so you can run it on your own hardware, through a cloud host, or both. Running it yourself removes the per-token bill of a closed API and replaces it with servers and staff.

Calling it through a vendor's API keeps the setup simple and charges per token. Most of the models here offer both routes, and the cheapest route depends on how many tokens you move each month.

If you only need a closed chatbot for daily work, our best AI chatbots list covers the paid options, and our private chatbots guide covers the data questions that self-hosting answers.

Why it matters

The price gap is the reason to read this list. Among the models with a paid API rate, DeepSeek V4-Flash is the cheapest on input and on output, and Kimi K3's output rate is 25 times the Flash off-peak output rate. A team sending 100 million input tokens a month sees that gap in its first invoice, not in a benchmark.

For the closed side of the bill, read our ChatGPT pricing, Claude pricing and Gemini pricing guides.

Key features to look for

LicenseEssential
MIT and Apache 2.0 are the simple cases for a commercial product. Kimi K3 uses its own license, so read it before you ship.
Context windowEssential
Three of the seven state a 1M-token context: DeepSeek V4, GLM-5.2 and Kimi K3. Gemma 4 offers 256K, enough for long documents but well short of the 1M-token models here.
Size
Parameter counts run from 27 billion for Qwen3.8-27B to 2.8 trillion for Kimi K3. The total sets the memory you need to self-host, and the active count per token sets how much work each answer costs the hardware.
Output price
Output tokens cost three to six times the input rate in every list here that publishes both. Read the output column first when you estimate a bill for long answers or agent runs.
Hosting route
Gemma 4 is free on the Gemini API's free tier, and OpenAI's API price list has no row for gpt-oss-120b, so the cost of those two depends on where you run them.

Pricing

Every price here is a list price on the vendor's own page, checked on 10 October 2026. DeepSeek publishes rates for two V4 models and doubles them in its weekday peak windows, 01:00 to 04:00 and 06:00 to 10:00 UTC.

Z.ai and Moonshot show a cached-input rate beside the regular input rate, and Alibaba's rate applies to its International endpoint, covered in our Qwen3.8-27B news piece.

Hosts such as OpenRouter let developers reach many models through one API, as our OpenRouter news piece explains.

The scenario is 100 million input and 20 million output tokens a month, with no cache hits and off-peak pricing.

On that basis DeepSeek V4-Flash comes to $27 a month, V4-Pro to $105.60, Qwen3.8-27B to $110, GLM-5.2 to $228 and Kimi K3 to $600. Flash in a peak window doubles to $54.

Caching lowers these totals, which is why the cached-input column matters.

Sources: DeepSeek API pricing, Z.ai pricing, Kimi API pricing, Alibaba Cloud Model Studio pricing, Gemini API pricing, OpenAI API pricing and Mistral pricing.

PlanPriceBest for
DeepSeek V4-Flash, off-peak$0.15 in / $0.60 out per 1MCache hit $0.003 per 1M input; 1M context; MIT weights
DeepSeek V4-Flash, peak$0.30 in / $1.20 out per 1MWeekday peak windows, 01:00 to 04:00 and 06:00 to 10:00 UTC
DeepSeek V4-Pro, off-peak$0.66 in / $1.98 out per 1MLarger model with no image input; cache hit $0.022 per 1M input
DeepSeek V4-Pro, peak$1.32 in / $3.96 out per 1MThe same model in the weekday peak windows
GLM-5.2 (Z.ai)$1.40 in / $4.40 out per 1MCached input at $0.26 per 1M; MIT weights; 1M context
Kimi K3 (Moonshot AI)$3 in / $15 out per 1MCached input at $0.30 per 1M; 2.8T parameters; vision; 1M context
Qwen3.8-27B, Alibaba Cloud International$0.50 in / $3 out per 1MThinking and non-thinking modes at one rate; a pricing tier for inputs up to 1M tokens
gpt-oss-120b (OpenAI)No OpenAI list priceHosts set the rate; weights are Apache 2.0
Gemma 4 on the Gemini APIFree of chargeFree tier only; the paid tier is listed as not available
Mistral Small 4No per-token list priceApache 2.0 weights; commercial terms may need a Mistral license
Mistakes to avoid
×Treating open weights as free to run. The download costs nothing, but serving a 2.8-trillion-parameter model like Kimi K3 is a hardware bill, not a license fee.
×Scheduling batch jobs at 01:00 to 04:00 UTC on a weekday. DeepSeek bills that window at its peak rate, which is double the off-peak price.
×Shipping a product on a model without reading its license first. Kimi K3 uses its own license, so check its terms before any commercial launch.
×Comparing headline prices and ignoring cache rates. A DeepSeek Flash cache hit costs 50 times less than a miss, so the same workload can cost very different amounts.
Expert tips
→Keep repeated system prompts identical so they hit the cache. A Flash cache hit costs $0.003 per 1M input tokens off-peak, against a miss that costs 50 times more.
→Run batch work at 04:00 to 06:00 UTC, after 10:00 UTC, or on weekends, when DeepSeek bills off-peak.
→Price the output column first. It costs three to six times the input rate wherever a rate is published, so long answers and agent loops raise the bill fastest.

The bottom line

For most buyers, DeepSeek V4-Flash is the first call: the lowest paid rate on this list, MIT weights you can self-host, and a 1M-token context.

Move up to GLM-5.2 when MIT terms and a long context matter more than price, and to Kimi K3 only if you can serve a 2.8-trillion-parameter model and accept its custom license.

For self-hosting under Apache 2.0, Qwen3.8-27B and Gemma 4 are the smaller choices.

If you want a closed model as the benchmark, see our ChatGPT review and Claude review.

Check prices again before you budget, because peak windows, cache rates and license terms change. Cite this: AIpresso, "Best Open-Source LLMs in 2026", October 2026, https://aipresso.com/reviews/best-open-source-llms.

Frequently asked questions

What is the best open-source LLM in 2026?
For most buyers, DeepSeek V4-Flash: the lowest paid API rate of the seven at $0.15 per million input tokens off-peak, with MIT-licensed weights and a 1M-token context. Choose GLM-5.2 when MIT terms and a long context matter more than price, and Qwen3.8-27B for a smaller Apache 2.0 model you run yourself.
Is there a free open-source LLM I can use without paying?
Yes, in two ways. You can download the open weights of most of these models without a license fee and run them on your own hardware, which costs you servers and electricity instead. Gemma 4 is also free to call on the Gemini API free tier.
How much does DeepSeek V4 cost per million tokens?
DeepSeek V4-Flash costs $0.15 per million input tokens and $0.60 per million output tokens off-peak, and $0.30 and $1.20 in the weekday peak windows of 01:00 to 04:00 and 06:00 to 10:00 UTC. V4-Pro costs $0.66 input and $1.98 output off-peak. These are DeepSeek's own listed rates, checked on 10 October 2026.
Can I use an open-source LLM in a commercial product?
Often yes, but the license decides it. DeepSeek V4 and GLM-5.2 use MIT. gpt-oss-120b, Qwen3.8-27B, Gemma 4 and Mistral Small 4 use Apache 2.0 according to their model cards or license pages. Kimi K3 uses its own Kimi K3 License. Mistral's pricing FAQ says commercial production use of its open-weight models can need a separate license, so check before you ship.
Should I self-host an open model or call an API?
Call an API when your volume is small or spiky, because you pay per token and nothing sits idle. Self-host when a steady workload or privacy rules justify the hardware and the serving software. Toolradar tracks 42 AI model deployment tools, and most of them have a free or open-source option, so the software is cheap to start even though the servers are not.
What does a monthly bill look like for an open-source LLM?
At 100 million input and 20 million output tokens a month, with no cache hits, DeepSeek V4-Flash comes to $27 off-peak, Qwen3.8-27B to $110, GLM-5.2 to $228 and Kimi K3 to $600. Your own mix of input, output and cache hits changes the total, so run your own numbers before you commit.
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