Reactorby Agencer

For people who build and run AI agents

Cut your agent's
AI bill by 60–85%.
Same quality.

Reactor sits between your agent and your AI models. It sends routine steps to a cheap model, and the rest to your best model.

Start free Why it is not a router

First month free. No savings, no fee.  60–85% is what we measured on our own agents.

Top gearyour best model Low gearyour cheap model
  • Top gear is your best model. It does the steps Reactor is not sure of.
  • Low gear is your cheap model. It does the routine steps.
Fig. 2Not a router

Why it is not a router.

A router picks a model for each step and hands the step over. If the pick is wrong, the step fails. Reactor shifts down only when it knows the cheap model will match your best model. If it does not know, your best model does the step.

Model 1 Model 2 Router

A router

It picks a model for the step. Then it is gone. If the pick was wrong, the step fails, and your agent fails with it.

Best model Cheap model Reactor SureNot sure

Reactor

It stays for every step. Sure: the cheap model does the step. Not sure: your best model does it. You get the same quality on both paths.

This is new technology. Patent pending. How Reactor decides is proprietary. What it did is on your dashboard, step by step.

Fig. 3What it does

Most steps are routine. You pay top price for all of them.

Your agent sends every step to your best model. Reactor moves the routine steps to your cheap model. Your best model still does the rest.

Today

One model for every step

Rename a file: top price. List a folder: top price. Read an email: top price.

With Reactor

The cheap model for routine steps

The same work. The same answers. Most steps now cost the low price.

Table 1The price

Try it free. Pay only if it saves you money.

The first month is free. After that, we keep 20% of what Reactor saves you. If it saves you nothing, you pay us nothing.

To start$3 of credit. No card. You get it when you confirm your email and add your first model key.
Month oneOur fee is 0%. For the first 100,000 accounts.2
After thatWe keep 20% of what Reactor saves you. You keep 80%. No minimum.
Model costsYou pay your model providers with your own keys, as you do now. Reactor adds no markup.
Start free$3 of credit. No card.
Fig. 4The proof

Our own agents cost 60–85% less to run.

Think of it this way: pay for Haiku, get Opus. You can use any two models. Your dashboard shows your real number, run by run.

60–85%1

Lower AI bill, on our own agents

We do not promise you a percentage. Your number depends on your agent's work. If it is zero, our fee is zero.

Example run41 steps
Best model alone$4.00
The same run, with Reactor$1.20
Saved$2.80
Our fee, 20% of saved$0.56
You keep$2.24
An example. Not a promise.
Fig. 5Setup

Start in five minutes. Change one line.

Your agent, your tools and your prompts stay the same. You only change where your agent sends its requests.

  1. Bring your two keys

    OpenAI, Anthropic, OpenRouter or Vercel AI Gateway. Pick your best model and a cheap model.

  2. Take a Reactor key

    One for each agent. Set a spend cap. Revoke it at any time.

  3. Point your agent at Reactor

    Change the address and the key. Then run your agent and watch the saving on your dashboard.

# your agent's model settings
base_url = "https://api.openai.com/v1"
base_url = REACTOR_URL      # from your dashboard
api_key  = OPENAI_API_KEY
api_key  = REACTOR_KEY

# the rest of your agent does not change
Table 2Plain answers

What is the catch? Here are the plain answers.

Will my agent get worse?
No. Reactor shifts down only when it is sure. A step that goes to your best model goes out and comes back untouched.
What if it saves me nothing?
Then our fee is zero. Your dashboard shows that too.
Does Reactor see my traffic?
Yes. Each request and each reply passes through it. That is how it shifts and how it measures the saving. The privacy policy says what we keep.
Can I delete my data?
Yes. Email us, and we delete your data or your account.
What if my cheap model is down?
All steps go to your best model at once. Your agent keeps running.
How do I leave?
Change the address back. There is nothing else to undo.
ModelsTwo. You choose both. You can change them at any time.
KeysYours. OpenAI, Anthropic, OpenRouter, Vercel AI Gateway.
Works withAny agent that speaks the OpenAI chat format and lets you set the address.
Your toolsReactor never runs them. Your agent does.

Cut the bill. Keep the quality.

Start freeFirst month free. No savings, no fee.

Reactor = the name is the machine

ReReal-time
AAdaptive
CContinual
TTransmission
OOn
RRails

1 Measured on Agencer's own agents, against the same work on the best model alone. Your result depends on your agent's work.   2 The free month starts at your first purchase. After it, the fee is 20% of what Reactor saves you.