How Truecaller Executes Rapid App & Documentation Releases in 48 Languages

Truecaller, the leading global caller ID and spam-blocking app, needed a localization setup that could keep pace with its fast release cycles. With users across Asia, Africa, and beyond, high‑quality translations in 48 languages – including rare languages – were critical for adoption and retention.  

Previously, this meant juggling multiple vendors and asking engineers to handle time‑consuming translation management tasks. By partnering with Milengo, Truecaller gained a single, reliable solution: automation, scalability, and linguistic expertise that minimized overhead and ensured stable, high‑quality releases. 

👉 Looking to simplify your app localization and documentation strategy?
Speak to a localization expert at Milengo and find out how we can help. 

At a glance 

About Truecaller 

Founded in 2009 in Stockholm, Sweden, Truecaller helps over 450 million monthly active users verify contacts, block unwanted communication, and connect with confidence. Especially strong across India, Africa, and the Middle East, Truecaller’s vision is clear: make tomorrow’s communication smarter, safer and more efficient.

Supporting users in their local language is essential for engagement and retention, making multilingual communication a cornerstone of its growth strategy. 

The challenge 

Rapid global growth put pressure on Truecaller’s app localization and documentation translation processes. Consistent app updates in 48 languages required tight coordination, but the team had no dedicated localization manager. Engineers often had to step in – managing vendors, handling manual content exports and imports, and reviewing translations. 

Vendor fragmentation drove up costs and slowed workflows. Finding reliable expertise for rare languages was difficult. Furthermore, reviews by native‑speaking colleagues sometimes revealed inconsistencies. Without a unified and scalable approach, both release speed and user experience were at risk. 

“Translations had been a long-lasting challenge for us. We needed a solution that could move in sync with our release cycles, deliver consistent quality, provide reliable support even for exotic languages, and lighten the load of project management on our internal teams.”

Dmitry Rahmanin, Staff Software Engineer

The solution 

Milengo created an automated localization workflow tailored to Truecaller’s fast release cycles. By consolidating everything under one partnership, Truecaller eliminated vendor sprawl, reduced engineering workload, and secured coverage for all languages – including rare ones. 

Key elements of the upgraded workflow  

• Consolidated coverage: One partner now manages all 48 languages, reducing vendor management overhead and ensuring consistency across product and marketing content. 
• Project management: A dedicated project manager, embedded in Truecaller’s workflows and using internal communication tools, aligns deadlines, handles ad hoc requests, and provides localization expertise. Acting as an outsourced localization manager, this freed engineers from administrative tasks.  
• Seamless technical alignment: As a language service integrator with proven expertise across a wide range of localization tools, Milengo began effortlessly working with Truecaller’s chosen translation management system (TMS), ensuring smooth integration and minimal disruptions to existing workflows. 
• AI‑Powered MT with human expertise: Truecaller uses Milengo’s ISO 5060-compliant AI‑enhanced machine translation product, TextGuard. This process ensures fast, cost‑efficient output while safeguarding accuracy. Furthermore, QA processes maintained high standards, and comparative testing across MT engines ensured the best match for each language pair, balancing speed, cost, and quality.
  
  For rare languages where machine translation engines have limited development or linguistic resources, Milengo ensures quality by providing human translation – maintaining accuracy, consistency, and brand voice. 

What is TextGuard?

TextGuard is Milengo’s AI‑driven machine translation solution that combines automation with expert human review. It gives companies like Truecaller fast, secure, and scalable translations – ensuring quality without slowing down release cycles. 

• Proactive linguists: Milengo linguists flagged terminology gaps and inconsistencies, enhancing content clarity across markets. This prompted reviews of previously translated content and established a feedback loop that strengthened product consistency. 

Milengo adapts to our release cadence and fluctuating volumes while still supporting ad hoc requests from other departments like marketing. That flexibility is exactly what we need in a product‑driven environment.

– Dmitry Rahmanin

 The results 

With Milengo, Truecaller now delivers multilingual updates on a predictable cadence. Software engineers can now focus on product development instead of managing localization. Improved translation quality resulted in a drop of QA escalations, and coverage for all 48 languages is now reliable – including rare markets. 

Dedicated project management and proactive linguists ensure localization never delays releases. Product managers can now plan confidently, knowing launches won’t be blocked by translation issues. Marketing also benefits, with Milengo handling ad hoc requests for campaign or article translations in any format. 

Key results

• Stable rapid release cycles 
• Reduced engineering overhead and fewer manual processes 
• Automated extraction and re‑import of content 
• Improved translation quality with fewer QA issues 
• Reliable rare‑language coverage from a single partner 

With Milengo, localization is now stable. That stability allows our teams to focus on product development and innovation instead of managing translation workflows.

– Dmitry Rahmanin

The future 

As Truecaller grows, Milengo remains a trusted partner for scalable localization. Next steps in the partnership include building termbases to address terminology gaps identified by linguists, adding visual context for linguists to improve accuracy, and involving linguists in future content testing. The partnership ensures localization stays efficient, predictable, and comprehensive – covering both common and rare languages without added complexity. 

We’re already extending Milengo’s expertise across departments. That trust speaks volumes about the value they bring.

– Dmitry Rahmanin

Disclaimer: Except in relation to the use of services and technology by Truecaller as detailed in this case study, all product descriptions and general details about services are provided by Milengo, and Truecaller makes no representation and is not responsible for their independent veracity.