Comparing 3 translation APIs - MyMemory vs DeepL vs Claude, what should I use?

I wanted to add a translation feature to my blog

Write a post in Korean and get an English draft with a single button.

It seems like a simple idea, but I had to switch between three different translation APIs to implement it. I started with MyMemory and ended up with DeepL, and in the process, I realized how different each service is.

Here's what I learned from my experience.

Three services at a glance

	MyMemory	DeepL	Claude API
Free Limits	1,000 characters/day	500,000 characters/month	None (pay-as-you-go)
Paid	Free 10,000 characters/day with email registration	From $6.99/month	Pay as you go
Cost per post	Free	Free	Around 4 cents
Markdown processing	Special character transformations	Well-preserved	Perfectly understood
Korean language quality	Low	High	Very High
API key	Not required	Required (card registration required)	Required

MyMemory - I started with it because it was free

When I first created the translation feature, I chose MyMemory for one reason and one reason only. No API key required.

const res = await fetch(
  `https://api.mymemory.translated.net/get?q=${encodeURIComponent(text)}&langpair=en|en`
);
const data = await res.json();
return data.responseData.translatedText;

In three lines of code, we have a translation. It's great for prototyping because there are few barriers to entry.

Problems

The more I used it, the more problems I encountered.

1. Markdown special characters are changed arbitrarily.

**Bold text** → * * Bold text * *

I kept seeing ** get split into * *, or transformed into something like __ BOLD __. To stop this, I kept adding code to insert and restore placeholders, but the API would deform the placeholders as well, resulting in an infinite loop.

2. 1,000 character limit

A single post quickly exceeds 1,000 characters. I had to create logic to break it up into chunks and request it multiple times, which resulted in awkward sentence breaks at chunk boundaries.

3. Translation quality

Honestly, it smells like machine translation. In particular, there were a lot of cases where Korean research and tone of voice didn't translate naturally to English.

Verdict: It's good for quick testing. However, it has clear limitations when it comes to real-world use.

DeepL - Quality is different

I switched to DeepL after continuing to experience markdown breakage issues with MyMemory.

Setup

The DeepL API requires card registration, even for the free plan. This is a barrier to entry, but you get 500,000 characters free per month. Even if you write a blog post every day, it's hard to use it up in a month.

Once you get your API key, create a server-side route and use it.

// app/api/admin/translate/route.ts
const res = await fetch("https://api-free.deepl.com/v2/translate", {
  method: "POST",
  headers: {
    Authorization: `DeepL-Auth-Key ${process.env.DEEPL_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    text: [text],
    source_lang: "EN",
    target_lang: "EN",
  }),
});
const data = await res.json();
return data.translations[0].text;

Do not call this directly from the client It must go through the server route because the API key is exposed to the browser.

Pros.

Preserves most special characters like Markdown **, ##, etc.
Korean to English translation quality is much better than MyMemory
Can process long texts at once (no chunking required)

Verdict: I'm happy with both the translation quality and the markdown handling. The free limit is sufficient. Card registration is the only barrier.

---.

Claude API - does better than translation

Claude is an LLM, not a translation API. But for translation purposes, it's actually better than DeepL.

const message = await anthropic.messages.create({
  model: "claude-haiku-4-5-20251001",
  max_tokens: 4096,
  messages: [{
    role: "user",
    content: `Translate the following Markdown text into English. Keep the markdown syntax intact.\n\n${text}`,
  }],
});
return message.content[0].text;

Advantages

Understands Markdown as a language, so preserves **, ##, blocks of code, etc.
No need for gimmicks like placeholder handling
Goes beyond simple translation to find natural, contextualized expressions
No need to sign up if you already have a Claude API key

Cons

Paid (pay-as-you-go). It's about 4 cents per post, so it's affordable, but not free
Can be a bit slower to respond compared to MyMemory, DeepL

Conclusion: If you have an API key, this is the best option. It eliminates the markdown preservation issue.

Which one should I use?

Situations	Recommendations
Quickly test prototypes	MyMemory
I want to write for free and can register my card	DeepL Free
Claude API key already in place	Claude API
Translation quality is our top priority	Claude API

I eventually settled on DeepL. I was tired of MyMemory's markdown breaking issues, and I already use the Claude API for other things, so I was a little hesitant to add translation to the mix. I found DeepL to have a good free limit and good quality.

Organization - core flow at a glance

Test/Prototype
  └── MyMemory (out of the box, no API key required)

Actual service
  ├── DeepL Free (500,000 free characters per month, card registration required)
  └── Claude API (pay-as-you-go, 1 post ≈ 4 cents, full markdown preservation)

Markdown preservation reliability
  MyMemory < DeepL < Claude API

I've used three APIs to add a single translation feature. At first, I thought that I could just use a free API, but the difference in quality is bigger than I thought. It would have been much faster to start with DeepL or Claude from the beginning.