If you buy translation services, you will encounter standards. Two appear more often than any others: ISO 17100 for translation services and ISO 18587 for the post-editing of machine translation. They are frequently invoked in proposals and on company websites, but what exactly do they require, and how much assurance do they really provide?

ISO 17100: the standard for human translation

ISO 17100 sets out requirements for the processes and resources involved in delivering translation services. It replaced the earlier European EN 15038 standard and has become an internationally recognised benchmark. Rather than judging individual words, it examines the system that produces them.

Its core requirements fall into a few familiar categories:

  • Human resources. Translators must have recognised translation qualifications or equivalent professional experience, and the standard defines the competences they are expected to hold, including linguistic, translational, research and technical skills.
  • The translation process. Crucially, the standard requires a separate review stage: a qualified person other than the translator checks the target text against the source. This four-eyes principle is one of the most practically valuable elements.
  • Technical and project resources. The standard covers project management, client communication, handling of data and the systems used to manage translation assets.
  • Traceability. Processes, queries and records must be documented, so that questions about how a text was produced can be answered.

ISO 18587: post-editing machine output

As machine translation moved into professional use, a separate standard became necessary. ISO 18587 addresses post-editing, the process by which a linguist reviews and corrects machine-generated text. It distinguishes between full post-editing, which aims for human-quality output, and light post-editing, which focuses on accuracy and readability for quicker use.

The standard defines the competences expected of post-editors, who must combine traditional translation skills with the ability to evaluate machine output efficiently. It also describes how clients and providers should agree on the intended quality level, because post-editing serves different purposes depending on the content and its readership.

What certification actually means

It is worth being precise about what these standards do and do not guarantee. Certification means that an independent auditor has examined the provider's documented processes and confirmed that they meet the standard's requirements. It provides genuine evidence of a structured approach to quality, qualified people and formal review, and it matters particularly to corporate and public-sector buyers who need assurance about their suppliers.

It does not guarantee that every sentence is perfect, because no process can. Quality also depends on clear source material, adequate briefings, realistic deadlines and constructive feedback between client and provider. A certified process cannot rescue an ambiguous source, an impossible deadline or a failure to communicate expectations.

Complementary frameworks

Translation standards rarely operate alone. Organisations supporting enterprise clients typically combine them with complementary frameworks: ISO 9001 for general quality management, ISO 27001 for information security, and increasingly specific controls for privacy regulation when personal data crosses borders. For interpreting, separate standards address service provision and conference arrangements, while subtitling and localisation work often follows industry specifications set by individual broadcasters and platforms.

The proliferation can look bureaucratic, but the underlying logic is coherent. Each framework governs a different risk: the quality of the language, the security of the information and the reliability of the management system. Mature suppliers map these frameworks together so clients receive consolidated evidence rather than a pile of unrelated certificates, and they align their everyday operations with the combined requirements rather than treating certification as an annual performance.

How buyers should use the standards

Treat ISO 17100 and ISO 18587 as useful filters rather than final verdicts. Certification is a sensible first requirement, particularly for high-stakes work, but experienced buyers also ask how the standards are applied in practice. Who reviews the work, and what are their qualifications? How are queries to clients handled? How is terminology maintained across projects? What security arrangements protect sensitive material? How is post-editing quality agreed and measured?

Standards work best as a foundation on which a genuine quality partnership is built. They establish the baseline processes; sustained quality comes from the people operating them and the relationship between client and provider. Understood in that light, ISO 17100 and ISO 18587 are genuinely useful: they describe what professional operation looks like in an industry where clients are entitled to evidence, not merely assurances.