The developer’s guide to choosing the right translation API

Translation APIs offer a way to integrate real-time translation into apps and systems. Learn how they work, and how to find the right API for your own needs.


API stands for “application programming interface.” A translation API, in turn, is a set of rules and protocols that allow software developers to integrate automatic or machine translation capabilities into websites, applications, or systems in a format customizable to their own systems.

While APIs can be built from scratch, developers who leverage pre-built APIs can save valuable time and resources. Key aspects and features of commonly available translation APIs include functionality and flexibility. This is key—at their most basic level, translation APIs allow two systems to talk to each other, taking a string of text in one language and then returning a translation of that text in another specified language (or languages) to the other application.

Software developers can embed these APIs in various tools and systems, including mobile apps, content management systems (CMS), IoT (i.e., Internet of Things) devices, and machine learning platforms. Once embedded, the API can send translated text in a variety of content and file formats, including HTML files, PDFs, presentations, social media posts, and Word docs.

Translation APIs increasingly support software and platforms that offer near or fully real-time translation functionality, which is vital for systems and applications involved in use cases like customer support and live chat.

Some of these services APIs support can also afford users high degrees of language customization. This ability for users to intricately customize the specifics of languages at play is particularly important in highly regulated industries.

It’s due in part to the wide variety of these features, and how widely they vary from product to product, that translation APIs commonly operate on a pay-per-use model. For users, these models will charge based on the number of words or characters translated, the net total of API calls over a given period, or other metrics.

Choosing the right translation API for your project

With the basic features and aspects of translation APIs covered, we can shift to how best to choose one for a specific project.

What follows are some basic steps and considerations, which you can then apply as you begin to vet potential APIs for your own development needs.

Start by making sure those needs are clearly defined and can be met:

  • Make sure a given API will connect to a system that can support all the languages that you need to be translated (both now and in the future).
  • Ensure you understand which content type you want to excel in (e.g., conversational, technical, healthcare).
  • Estimate the volume of translations you'll need to execute, as some APIs work best at either high or low scales.

Then, be prepared to rate APIs on both accuracy and quality. Determine whether you can customize a given API by training it on provided datasets, especially if your users will need high accuracy in specific contexts. Also, it's advisable to test APIs with relevant sample texts to judge the quality of their translations.

Next, see if the API providers offer software development kits and libraries in your programming language of choice (e.g., Python, JSON, etc.). Additionally, vet the technical support these providers offer, especially if you must commit to a long-term contract. Remember that well-documented translation APIs will be much easier to integrate and use.

Clocking each translation API's potential performance and scalability is vital. Check to see if a given API has request rate limits. For APIs that do, determine if those limits will align with your estimated usage. Utilize use cases requiring real-time language translation to test API response time, ensuring it will meet your needs. Also, ensure the API can maintain the necessary performance as your user base or content volume grows.

Regarding security and compliance, review how an API provider will handle and store your data:

  • For use cases involving sensitive content and information, all data must be encrypted and stored no longer than is needed.
  • In highly regulated industries like finance and healthcare, the API provider must also comply with all relevant regulations, such as the EU's GDPR.

In addition to security and compliance features, API providers are increasingly offering translation-related services like sentiment analysis, text-to-speech, and language detection—each may be more or less relevant to your goals.

Often, these features make it worth trying out an API before talking contracts and terms. Does the provider offer the ability to trial the API first? If so, the free tier or trial period can allow for valuable hands-on testing and evaluation.

At this point, with all these different facets understood, compared, and contrasted, you'll naturally arrive at pricing and reputation. Just like features, pricing models must align with how your API will be used. Costs can, for instance, be based on characters and total words translated or the amount of calls made to the API.

Compare and contrast terms of service related to any API that lands on your shortlist:

  • Contract duration
  • Service level agreements (SLAs)
  • Potential termination clauses
  • Hidden costs

Former and existing users often note unwelcome surprises. Make it a point to also research trusted review sites for user feedback and testimonials, especially those in related industries or use cases.

Moreover, active, healthy communities (be they large or not) can serve as an additional indicator that an API is reliable and experiencing wide use.

Top API-friendly translation products worth trying first

Smartling's API

Some of the largest and most trusted brands utilize our robust translation API to seamlessly scale their translation across apps and websites.

Developers often choose the Smartling API due to the following:

  • REST APIs for scalable web services: The preferred API technology for connecting and interacting with cloud-based software
  • SDKs for Java, Python, and PHP to move quickly
  • CLI for file management: Fast access to API endpoints from your terminal—open source and available on GitHub
  • HTTPS requests structured in JSON: Smartling’s Translation API uses defined HTTPS requests to ensure data privacy and structured JSON responses for smooth integration
  • Real-time status reporting for full visibility

IBM Cloud API Language Translator

IBM’s translation API is part of its cloud services and offers translation and multilingual identification capabilities using neural machine translation (NMT).

Designed for enterprise-level applications, IBM's API is a solid contender for devs already using other IBM cloud services. However, any developer requiring customization functionality for enterprise-scale projects should consider it.

Microsoft Text Translate API

Microsoft offers its own translation API as part of Azure Cognitive Services. Their text translation capabilities are powered by machine learning, support multiple languages, and can handle real-time and batch processing.

In addition to offering similar ecosystem-based benefits as IBM's API, Microsoft Text Translate also offers developers language detection and transliteration.

Google Cloud Translation API

Google also offers a translation API as part of its Google Cloud services and is built on the same infrastructure as Google. It provides dynamic real-time and batch translations for thousands of language pairs.

Developers may choose this API when their project requires fast translations for a wide variety of languages and can benefit from Google's frequent improvements to machine learning.

Amazon Translate API

Amazon Translate is another NMT API built to deliver fast, high-quality, and affordable language translation. The API allows for real-time and batch translations and can be optimized for a wide range of applications.

Amazon's API also leverages natural language processing (NLP), which makes it possible for the API to understand customer sentiments regarding services, products, or brands.

Common challenges of API implementation (and 4 specific to translation APIs)

There are common challenges you can expect to face when implementing any API. However, translation API implementation does require a few specific considerations, which are also listed below.

Perhaps the most common challenges experienced with APIs relate to their day-to-day use:

  • Rate limit restrictions
  • Managing costs
  • Scaling infrastructure without affecting performance (i.e., uptime)
  • Integrating new APIs with older systems

Other common API challenges may include factors that aren’t under the direct control of IT teams:

  • Latency issues: APIs that must perform in near-real-time are particularly vulnerable to latency issues, which can severely degrade the user experience.
  • Data privacy and security concerns: Sending data to external services can pose security risks, especially if the data relates to sensitive or highly regulated information.
  • External service dependencies: Reliance on an external API means that downtime or issues with that API's external provider are beyond the control of internal teams.

4 Implementation challenges specific to translation APIs

While integrating and scaling any API in an IT environment comes with challenges, translation APIs can present specific issues due to their specialization with language:

  1. Translation inconsistencies: When APIs translate content, care must be taken to ensure terminology and phrasing remain consistent.
  2. Language limitations: While many translation APIs support many languages, not all languages within a user base may be represented, especially if some of those languages are less common.
  3. Maintaining context: Some use cases require translations with a high degree of accuracy. If the API cannot maintain context through an interaction, translations of standalone sentences may be technically correct but contextually wrong.
  4. Handling translation errors: It's also important to remember that no translation API (no matter how advanced) is immune from simply making a mistake, resulting in a translation being technically and contextually incorrect.

Best practices for implementing a translation API

Like most aspects of the software development process, translation API implementation comes with many best practices to keep in mind:

  • Prioritize data security: Even if your API won't be handling highly regulated or sensitive information, ensure any data provider you're vetting follows clear and strict data security protocols and reviews their data retention policies. Additionally, always (always) use encrypted connections.
  • Stay on top of updates: While discussing data security with providers, also get a sense of how you'll need to stay ahead of API updates or service changes. Plan to check for updates regularly, read all available documentation, and adjust your implementation plans accordingly.
  • Utilize language support: You'll also need to regularly check if an API provider has made improvements or added support for new languages, especially when you're expanding to new markets.
  • Thorough testing: Test with various types of content before fully integrating any translation API. In addition to validating what you initially like about it, pre-testing will help you gauge an API's strengths and weaknesses.
  • Design with the reality of rate limits in mind: Don't resign yourself to handling rate limits when (or if) they become an issue. Instead, build a resilient system to handle these limits without crashes or disruptions.
  • Expect to scale: Growth is a good problem to have. As part of building a resilient system to support your API, make sure that infrastructure and any integrations can scale to increased loads.
  • Cache translations: Consider adding additional resilience to your system by being prepared to cache frequently requested translations. You can then utilize cached translations without redundant calls to the API, which increases performance and reduces costs.
  • Keep ahead of those costs: Instead of checking in on your usage from time to time, set up alerts or limits to notify you when you're approaching your budget.
  • Implement a feedback mechanism: Finally, allowing users to provide feedback on translation quality is advisable. While this can help you identify areas that need improvement, feedback often allows you to improve the translation accuracy of your application.

Moving from how to why for the right API

As software developers know, every API has its own specific features, endpoints, and capabilities (even when designed to offer the same service, like language translation).

But, the fact that translation APIs are built to work with language, one of our most innate abilities, makes them unique. The standards they must perform at are high by default, so it's much more important to pick the right one for the job. This is why the best thing to do after reading an article like this is to dive in and try some of these APIs yourself.

For more personalized insights into how Smartling can help you localize your next marketing campaign with ease, schedule a chat with one of our experts.