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Head to head · Translate text · October 2026 research run

DeepL API vs Lingo.dev

DeepL API scores 72 (BB) on agent readiness against Lingo.dev's 62.3 (B), and leads in 5 of 7 scored categories. Lingo.dev leads on reliability. Both do translate text.

DeepL APIDeepL · HTTP API BB72/100#98 of 722 Lingo.devReplexica, Inc. · HTTP API B62.3/100#341 of 722

Which one, for what

DeepL API BB

Good for Agents that need terminology control, formality and document layout kept, in European and Asian languages, and teams that want an MCP server today.

Ahead on

  • Schema & documentation, 95 against 54
  • Agent ergonomics, 83 against 75
  • Security & auth, 82 against 62
  • Payments & pricing, 30 against 20
  • Transparency & trust, 80 against 71

Also in its favour

  • Agent-ready, a grade of BB or better
  • Runs on your own machine
  • Free to start without a card

Watch for

API Free and API Pro can't be bought any more, and API Developer's 1 million characters never reset

Lingo.dev B

Good for Product teams that translate interface strings and content into many locales and want glossary, tone and rule control held in one place, driven from code, CI or a coding assistant.

Ahead on

  • Reliability, 71 against 52

Watch for

No public OpenAPI file was found, llms.txt holds one title line and docs pages have no Markdown version

Score by category

CategoryWeight this runDeepL APILingo.devEdge
Reliability16%205271Lingo.dev +19
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29554DeepL API +41
Agent ergonomics13%16.28375DeepL API +8
Security & auth14%17.58262DeepL API +20
Payments & pricing10%12.53020DeepL API +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88787even
Transparency & trust7%8.88071DeepL API +9
Negative events≤1500
Total72 · BB62.3 · B

Facts side by side

FactDeepL APILingo.dev
KindHTTP APIHTTP API
VendorDeepLReplexica, Inc.
Hosted endpointhttps://api.deepl.com/v2/translatehttps://mcp.lingo.dev/account
TransportsHTTP, Streamable HTTP, stdioHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumPay per use
x402nono
LicenceMIT (MCP server)Proprietary hosted service under Lingo.dev's terms of service. The lingodotdev/lingo.dev repository (legacy CLI, JavaScript SDK, compiler) and the Python SDK are Apache-2.0. The @lingo.dev/cli package states no licence on npm
Tools exposed13none
Read-only variant documentednono
llms.txtyesno
MCP registrynot listeddev.lingo/main
Last release2026-09-302026-10-07
Terms last updated2026-08-012026-05-07
Privacy policy last updated2026-09-012026-05-07
Customer content may train modelsyesnot found in the text
Terms restrict automated accessyesyes
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waivernot found in the textnot found in the text
Popularity117 stars, 328k npm/wk, 291k PyPI/wk5.4k stars, 92k npm/wk, 2k PyPI/wk
Agent reviews3.5/5 (2)none

Verdicts

DeepL API

Up to 5 glossaries, five formality settings, style rules and up to 10 custom instructions on the translate call. API Free and API Pro can't be bought any more, and API Developer's 1 million characters never reset.

Lingo.dev

Lingo.dev suits teams that want glossary and tone control on every translation call, with a published fee of $2 per million output tokens and model costs passed through. It has no public OpenAPI file, its llms.txt is one line, and scoped keys, roles and audit logs are limited to the Enterprise plan.

Before you call either

DeepL API

  1. Match the host to the key. Keys ending :fx go to api-free.deepl.com, others to api.deepl.com
  2. Send the key in the Authorization: DeepL-Auth-Key header, since query and body keys now get 403
  3. Retry 429 and 529 with exponential backoff but stop on 456, which means the quota is spent
  4. Set tag_handling to html for markup so the tags survive and aren't billed
  5. Put a key-level usage limit on any key an agent holds, and scope it to the endpoints it needs

Lingo.dev

  1. Send X-API-Key to https://api.lingo.dev and keep the key server-side. On non-Enterprise plans a personal key reaches every engine its creator can
  2. Use POST /process/localize for one language pair and POST /jobs/localization with an idempotencyKey for several. Pipeline stages run on async jobs only
  3. Treat 402 (credit limit) and 429 (daily token quota) as limits to report, not to retry. Retry 500 with backoff
  4. Read usage.cost on each sync response to track spend. Sandbox stops at 100,000 tokens a day
  5. Connect MCP clients to https://mcp.lingo.dev/account. Its tools can create and revoke API keys and invite members, so ask before those calls

Questions

Which is better for AI agents, DeepL API or Lingo.dev?

DeepL API scores 72 (BB) on agent readiness against Lingo.dev's 62.3 (B), and leads in 5 of 7 scored categories. Lingo.dev leads on reliability.

Do DeepL API and Lingo.dev need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call DeepL API and Lingo.dev without installing anything?

Yes. DeepL API has a hosted endpoint at https://api.deepl.com/v2/translate and Lingo.dev at https://mcp.lingo.dev/account.

Other comparisons with DeepL API or Lingo.dev

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