Credits
How the Proofademic credit system works — plans, billing, and usage.
How Credits Work
Credits are one shared pool across all services. Most endpoints consume credits based on the word count of the input text.
1 credit = 1 wordThree services price differently:
- The Plagiarism Checker charges a flat 2 credits per scan, regardless of text length.
- The AI Voice Detector charges 10 credits per second of audio (see Voice Detection Pricing below).
- The Image Detector is priced by image resolution (see Image Detection Pricing below).
| Service | Cost |
|---|---|
| AI Detector | 1 credit per word |
| Plagiarism Checker | Flat 2 credits per scan |
| Grammar Checker | 1 credit per word |
| AI Voice Detector | 10 credits per second of audio |
| Image Detector | By image resolution (see below) |
Word-based charges use a script-aware count (whitespace-separated words; one word per character for CJK scripts). Failed requests are refunded automatically.
Voice Detection Pricing
The AI Voice Detector charges credits based on the audio's duration:
credits = ceil(duration_in_seconds) × 10The duration is rounded up to the whole second, with a minimum of 1 second (10 credits). At the maximum length of 10 minutes, a scan costs 6,000 credits. The exact amount is returned as credits_used in every successful response.
Image Detection Pricing
The Image Detector charges credits based on the image's resolution in megapixels:
tokens = 197 + 50 × megapixels
credits = max(6, round(tokens / 36.5))Each image costs at least 6 credits. Images larger than 4K UHD (3840 × 2160, ≈8.3 MP) are virtually downscaled before pricing, capping the charge at 17 credits. The exact amount is returned as credits_charged in every successful response.
Checking Your Balance
Every successful API response includes a credits_remaining field showing your current balance after the request.
{
"status": "success",
"result": "ai",
"ai_score": 0.87,
"credits_remaining": 1482
}Plans
| Plan | Credits / month | Price / month |
|---|---|---|
| 300K | 300,000 | $49 |
| 1M | 1,000,000 | $129 |
| 2M | 2,000,000 | $229 |
| 5M | 5,000,000 | $479 |
| 12M | 12,000,000 | $899 |
| 25M | 25,000,000 | $1,699 |
Credits reset monthly on your billing cycle. Unused credits do not roll over.
Free Trial
New accounts start with a free trial — no credit card required.
- 2,000 credits included.
- 5 days to use them.
- Once the trial expires or credits run out, upgrade to a paid plan to continue using the API.
Insufficient Credits
If your credit balance is lower than the word count of the submitted text, the request is rejected with 403:
{
"error": "Insufficient credits",
"code": "insufficient_credits",
"details": {
"credits": 50,
"required": 120
}
}Credits Exhausted (Paid Plan)
If your monthly credits are fully used, requests return 403 until the next billing cycle:
{
"error": "Credits exhausted. Credits reset on next billing cycle.",
"code": "credits_exhausted",
"details": {
"plan": "1M",
"credits": 0
}
}Trial Expired
If your trial period has ended, requests return 403:
{
"error": "Trial expired, please subscribe",
"code": "trial_expired"
}