"AI API" used to mean one thing — call OpenAI. The free-tier landscape now spans five distinct categories: text generation, speech-to-text, voice synthesis, translation, and vision. This shortlist picks the strongest free option in each category, all of which you can integrate without entering payment details.
Quick comparison
| API | Category | Auth | Free tier signal |
|---|---|---|---|
| Google Gemini | Text generation (LLM) | API key | Free |
| AssemblyAI | Speech-to-text | API key | Free |
| ElevenLabs | Text-to-speech | API key | Free |
| Azure AI Translator | Translation | API key | Free (2M chars/month) |
| Google Cloud Vision | OCR and image analysis | API key / service account | Limited |
What "free" actually means here
For an AI API to qualify, you should be able to:
- Sign up without entering payment details to access the free tier.
- Run real prototype workloads, not just a demo notebook.
- Find documented quota limits before you commit code to production.
AI free tiers move faster than any other category — model versions change, quotas tighten, and pricing pages get rewritten. Always re-verify against the official docs at integration time.
API options
Google Gemini API — text generation
The Google Gemini API is the strongest free option for general-purpose LLM work. The gemini-2.0-flash model is available without billing setup and handles text generation, summarization, code, translation, and multimodal inputs (text + images).
Use it when:
- You need a capable LLM for prototyping without OpenAI billing.
- You want multimodal input (image + text) in a single request.
- You can work within Google's free-tier rate limits.
The integration is medium complexity — the request shape is straightforward, but the safety settings and structured output options take some reading.
AssemblyAI — speech-to-text
AssemblyAI is a strong choice for converting audio to text. It supports transcription, speaker diarization, sentiment analysis, and automatic topic extraction, all from the same API.
Use it when:
- You are building anything that turns audio into text: meeting transcripts, podcast indexers, accessibility tools.
- You want speaker diarization out of the box.
- You can stay within the free-tier quota.
Integration complexity is low — upload audio, poll for transcription, read the result.
ElevenLabs — text-to-speech
ElevenLabs goes the other direction: generating realistic voices from text. The free tier includes pre-built voices in multiple languages, with voice cloning available on paid plans.
Use it when:
- You are adding narration to videos, podcasts, or e-learning content.
- You need character voices for games or animations.
- You are building accessibility features (text-to-speech reading).
The free quota is character-count based and small enough that production use will quickly require a paid plan, but it is more than enough to validate the integration.
Azure AI Translator — translation
Azure AI Translator covers 137 languages including Turkish, with 2 million characters per month on the free tier. It also supports language detection, transliteration, and bilingual dictionary lookup.
Use it when:
- You need machine translation with broad language coverage.
- You want strong support for Turkish, Arabic, or other non-Latin-script languages.
- You can work inside Microsoft's auth model (API key plus region header).
Integration complexity is medium because the request shape is opinionated, but the documentation is solid.
Google Cloud Vision — OCR and image analysis
Google Cloud Vision provides OCR, label detection, face detection, and document classification. The free tier is limited but workable for prototypes and low-volume products.
Use it when:
- Your product needs OCR — invoice parsing, document digitization, text extraction from images.
- You want a multi-feature vision API instead of stitching together specialized models.
- You can work within KVKK / GDPR data residency constraints (data goes to Google).
For Türkiye-targeted products handling personal documents, double-check residency requirements before committing.
Picking the right one
Match the API to the task, not the buzzword:
- General LLM prototyping → Google Gemini.
- Audio to text → AssemblyAI.
- Text to audio → ElevenLabs.
- Translation, especially Turkish or many languages → Azure AI Translator.
- OCR or image analysis → Google Cloud Vision.
Most real products end up combining two or three of these — for example, a podcast app might use AssemblyAI for transcripts plus Gemini for summaries.
When not to use these APIs
Free AI tiers are excellent for prototypes, but they have limits:
- Production traffic at scale. All five free tiers are bounded. Plan for paid plans before you go live with a consumer product.
- Strict data residency. Google and Microsoft route data through their cloud regions; Azure exposes region selection but Google Vision's residency model is less granular. For sensitive workloads, evaluate carefully.
- Latency-critical interactive features. Free tiers are not optimized for low-latency interactive apps. For voice agents or real-time copilots, expect to upgrade.
Related API Deposu entries
Sources
Frequently Asked Questions
›Which AI API has the most usable free tier for LLM tasks?
The Google Gemini API is the strongest free option for general LLM work — Gemini 2.0 Flash is available without billing setup, and supports text, code, and image inputs.
›Are these APIs really free, or just trials?
Gemini, AssemblyAI, ElevenLabs, and Azure AI Translator have proper free tiers. DeepL and Google Cloud Vision are time- or quota-limited and behave more like trials at scale. Always verify the current limits in the official docs.
›Can I use the free tiers in production?
For low-traffic or internal tools, yes. For consumer-facing or high-volume features, you should plan for paid plans early — free tiers exist to validate the integration, not to power your product indefinitely.
›Which AI API is best for Turkish-language workloads?
Azure AI Translator covers 137 languages including Turkish and gives you 2 million characters per month free, which is generous for translation. For Turkish-aware text generation, Gemini handles Turkish prompts well in practice.