developer guides for the FastSaverAPI endpoints
Four code-first guides, each built around something people actually ship. Every one starts from an empty file and ends with something that runs — including the error paths most tutorials leave out, and what each call actually costs.
index
the guides
Four walkthroughs, each built around something people actually ship. Every code sample runs
against the live API — no pseudocode, no ... standing in for the hard part.
Build a Telegram music bot
python · aiogramSearch YouTube Music, then answer with a cached file_id — no file ever touches your server. Full aiogram 3 handler.
Download Instagram reels in Python
python · requestsFrom a naive call to a batch runner with streaming, retries and timeouts. Why the CDN URL expires and what that means for a queue.
YouTube to MP3 over HTTP
python · nodeExtract audio without yt-dlp or ffmpeg on your own box — and an honest account of what you give up by not running them.
TikTok without the watermark
explainer · codeWhy the clean render is hard to get, why cropping and re-encoding are the wrong answer, and what the API hands back instead.
setup
what you need before any of them
All four guides assume the same two minutes of setup.
- An API key. Sign up at api.fastsaver.io — the free tier gives you 1,000 credits and does not ask for a card.
- An HTTP client.
requestsin Python,fetchin Node,curlat a prompt. No SDK exists and none is needed. - The key in an environment variable, not in the source file you are about to commit.
export FASTSAVER_KEY="fs_sk_•••••••••••"
curl "https://api.fastsaver.io/v1/balance" -H "X-Api-Key: $FASTSAVER_KEY"If that returns "ok": true with your plan and credit balance, every guide here
will work as written.
shared ground
the four errors you will actually hit
Rather than repeat error handling in every guide, here is the whole surface once.
| Status | detail | What to do |
|---|---|---|
| 401 | Invalid API key | The key is missing, mistyped, or was dropped by a client following a redirect. Send X-Api-Key straight to the current base URL. |
| 400 | Insufficient credits. Please top up to your account. | Out of credits. Match on the detail string — the status is a plain 400, not a 402. GET /balance is free, so poll that instead of guessing. |
| 429 | Rate limit exceeded… | You passed your plan's requests-per-minute limit. Back off and retry; a token bucket beats a retry loop. |
| 400 | ok: false with a reason | The link is private, deleted, region-locked or not a supported platform. Surface it to the user — retrying will not help. |
Two things surprise people here. There is no 402 — running out of credits
answers a plain 400, so branch on the detail string rather than the
status code. And ok, not the status, is the real success flag: read it first and
every integration gets simpler.
updates
follow along
New guides are added as endpoints change. There is an RSS feed if you want them, and the Telegram channel carries API changes and incident notes.
Pick a guide and ship something today
Each one goes from an empty file to working code. The free tier covers all four end to end.