A plain-English guide to the standards that show up in translation RFPs — what each one certifies, what it does not, and how to read a certification claim.
- Three standards, three different promises
- What each one does — and does not — tell you
- How to use certifications in a decision
Three standards, three different promises
Certifications appear in almost every language-services RFP, and they are routinely misread as interchangeable proof of "quality". They are not. Each certifies a different thing, and knowing which is which stops you from over- or under-specifying.
ISO 9001 certifies a quality management system — that the organization has documented processes and follows them. ISO 17100 is specific to translation services and covers translator competence, the revision step and project records. ISO 18587 covers the post-editing of machine-translation output. They stack rather than compete.
What each one does — and does not — tell you
ISO 9001 tells you a process exists; it says nothing about whether a translator understands your subject. ISO 17100 requires a separate reviser from the translator and defines competence requirements, which is a meaningful bar — but it does not guarantee domain expertise in your specific field.
ISO 18587 matters as AI drafting becomes standard: it defines what a qualified human post-editor does to machine output. A vendor claiming "AI + human" without reference to a defined post-editing standard is describing an aspiration, not a process.
None of these certify the correctness of any individual translation. They certify that a system is in place. That is valuable as a floor, and useless as a substitute for evaluating domain fit.
How to use certifications in a decision
Treat them as a screen, not a ranking. Require the certifications your regulated content genuinely needs, then evaluate domain expertise, terminology practice and accountability on top — because those are what determine whether your datasheet or submission is actually right.
Ask which certifications apply to the specific service line you are buying, and to which sites. A certification held by one entity does not automatically cover a subcontractor doing your work. Angel Translation operates an ISO 9001:2015 certified quality system, and pairs it with LISA QA 3.1 audits at its expert-led tier — the audit is where a specific translation is actually checked.