Quick answer
Kraken.io - For most builders, Kraken.io wins because it offers a clearer free-to-paid path with real testing quota and published usage-based plans, while reSmush.it is simpler to start with but its commercial path is opaque.
How the free tiers compare
These are both image compression services, but they serve different builder situations. Kraken.io gives you a small but real sandbox: 100 MB of free testing quota, no credit card required, and the same ecosystem around the API, web app, and plugins that carries into paid usage. That makes it easier to evaluate and then scale into a published usage-based plan when you outgrow the free allowance. reSmush.it is the lower-friction forever-free option for personal use, with no usage restriction except a 5 MB upload cap, but the tradeoff is that commercial use goes to contact sales rather than a posted price ladder. So Kraken.io is better for builders who expect to grow or need predictable pricing, while reSmush.it fits small personal projects that want to stay free.
Kraken.io vs reSmush.it free tier, side by side
| Kraken.ioFTV 50 | reSmush.itFTV 57 | |
|---|---|---|
| Free allowanceKraken.io is a monthly testing quota; reSmush.it is free for personal use with a size cap. | 100 MB of testing quota | No usage restriction except uploaded file size |
| Upload/file size limit | Not stated in the free-tier facts provided | Uploaded files must be less than 5 MB |
| Credit card requiredBoth inputs explicitly say no credit card is required. | No | No |
| Free API accessreSmush.it limits the free API by use case rather than a published monthly quota. | Free API sandbox access with 100 MB of free quota for real optimizations | Free API access for personal use only |
After you outgrow the free tier
Kraken.io uses published usage-based pricing with a clear ladder: Micro at $5/mo, then $9, $19, $39, and $79 as capacity rises, plus overage charges per additional GB. reSmush.it does not publish a standard paid tier in the provided data; commercial or business use goes to contact sales for a personalized solution. For small teams that need known monthly spend, Kraken.io is more predictable. For simple personal use, reSmush.it stays free, but once you need commercial terms its pricing is not transparent here.
Cost at real usage
| Usage | Kraken.io | reSmush.it |
|---|---|---|
| 100 MB of optimizations/moreSmush.it still requires uploads under 5 MB per file. | Free (within tier) | Free (within personal-use terms) |
| 500 MB of optimizations/moKraken.io Micro includes 500 MB. | $5/mo | Free (within personal-use terms) |
| 2 GB of optimizations/moKraken.io Basic includes 2 GB. | $9/mo | Contact sales / varies by usage |
| 6 GB of optimizations/moKraken.io Advanced includes 5 GB, so 6 GB would likely require overage; the input gives overage pricing of $3 per additional GB on that plan. | $19/mo | Contact sales / varies by usage |
Estimates, not quotes. Usage-based rates change - verify with the vendor's pricing page before committing.
When to pick each one
Pick Kraken.io when…
- You want a free trial that feels close to the paid product, with 100 MB of real testing quota.
- You need a published upgrade path once you outgrow the free tier.
- You are evaluating image optimization across API, web interface, WordPress, or Magento and want the same vendor path as usage grows.
- You expect commercial use and want to see pricing before you commit.
- You need no credit card at signup and a small but defined monthly allowance.
Pick reSmush.it when…
- You are building a personal project and want free API access with no ongoing quota cap other than file size.
- Your uploads are always under 5 MB and you do not need a paid plan soon.
- You mainly need WordPress plugin or simple API compression for non-commercial use.
- You want the simplest forever-free option and can live with the personal-use-only terms.
- You are okay with contacting sales later if the project becomes commercial.
Bottom line
For the most common builder case, Kraken.io is the better pick because it gives you a usable free sandbox, a published price ladder, and a clear path to paid usage when your image volume grows. reSmush.it is the better free-only choice if your work is personal, your files stay under 5 MB, and you are fine with a commercial upgrade that is not publicly priced. If you expect to ship, measure, and then scale, Kraken.io is the safer bet.
Read the full listings: Kraken.io and reSmush.it. Scores use the FTV methodology at /ftv. Browse more head-to-heads on /compare, or see the top-ranked free tiers on /top.