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API · Open weights

ChindaMT

Thai and English translation that follows your rules.

  • Price1IC / 400 characters
  • One sentence0.4s
  • Native speakers prefer it2 to 1
  • Open weights4B · 2B · 0.8B

Try itRead the API

Published at AACL-IJCNLP 2026, Main Conference. Models and code under Apache 2.0.

TH

ประชุมเลื่อนไปวันศุกร์ เพราะหัวหน้าติดงาน

Without rules

The meeting has been rescheduled to Friday because the supervisor is busy with work.

With a ruleUse a casual tone

The meeting's been pushed to Friday since the boss is swamped with work.

Outputs of ChindaMT-4B published at its launch, replayed here; the run is the same every time.

What it does​

Translates Thai and English in either direction and follows the rules sent with the text: short instructions in plain English, of the five kinds it was trained on. A rule works best when it is specific and can be checked in the output.

  • Thai and EnglishBoth directions, one text or a batch of up to 100,000 characters, each line translated on its own.
  • TerminologyTranslate บาท as THB, Keep product names in English
  • Tone and registerUse a formal, polite tone suitable for a business email
  • LengthKeep it short enough for a subtitle, Use exactly one sentence
  • FormatReturn only the translation, no quotes, Keep the numbering of the list
  • LanguageAvoid English contractions, Write numbers as digits

Measured​

How often a judge model chose ChindaMT's translation over a rival's when rules were given, corrected for answer length.

ChindaMT chosenA tie, or the other model chosen

ChindaMT-4B, compared with

  • Typhoon-Translate-1.5-4B68.4%
  • TranslateGemma-4B87.2%
  • MiLMMT-46-4B89.5%
The line marks 50%, where the two would be even. The hosted API serves ChindaMT-4B.
  • Native speakersThree native Thai speakers chose ChindaMT-4B over Typhoon-Translate-1.5-4B 2 to 1 in a blind test: 64% of plain translations, 69% of translations with rules.
  • Without rules90.7 on FLORES-200 (the mean of CometKiwi, GEMBA-DA and GEMBA-MQM), the highest of the 4B to 9B models tested; 87.8 on WMT24++ news, second to a 7B model at 89.4.
  • Speed0.36 s for a sentence, 0.71 s for a page and 1.72 s for five pages, through the gateway from Bangkok.

Methods and the full tables are in the paper.

Fully open​

Limits​

  • Thai and English only.
  • It follows rules a good reference translation could satisfy. Strict placeholder tokens and a long mandatory glossary are outside what it was trained for.
  • Like any machine translation, it can read fluently and still be wrong: have legal, medical and other high-stakes text reviewed. The API marks the parts most likely wrong.
  • 100,000 characters and 2,000 characters of rules per request; 5 requests per second per API key.

On your own servers​

The open weights run on your own GPU. For an on-premise deployment with your own terminology, write to sale@iapp.co.th.