Base64 encode et decode en ligne gratuit

Base64 encode et decode en ligne

Pour « base64 encode », « base64 decode » ou « base 64 encoding », il faut un convertisseur rapide sans inscription. Cette page encode à gauche et décode à droite, en mode live, UTF-8 et tous les dialectes courants—dans votre navigateur.

Besoin d’une page dédiée ? Base64 encode online · Base64 decode online · String en Base64 · Image en Base64 · MP3 vers Base64 · Base64 vers WAV · URL vers Base64.

Aussi populaire dans la recherche : Test de compression gzip · Générateur de lien WhatsApp · Générateur de hashtags LinkedIn · Générateur de hashtags pour Twitter · Générateur de hashtags Facebook · Vérificateur IBAN · Convertisseur d’octets · Vérificateur de contraste des couleurs.

Pourquoi utiliser ce convertisseur Base64 ?

• Confidentiel par conception. Votre texte et vos fichiers sont traités localement en JavaScript. Même les fichiers volumineux ou confidentiels ne quittent jamais votre appareil.
• Gère le Base64 du monde réel. Les data URI, sauts de ligne, caractères URL-safe et remplissage manquant sont acceptés automatiquement, et les erreurs indiquent le caractère exact.
• Toutes les normes. RFC 4648 standard, Base64URL, MIME, PEM, IMAP, XML et armure OpenPGP.
• Tous les jeux de caractères. UTF-8, UTF-16, Windows-125x, ISO-8859-x, Shift_JIS, GBK, Big5, EUC-KR, KOI8 et bien d’autres.
• Résultat prêt à coller. Obtenez une data URI, une règle CSS, une balise HTML ou un extrait JSON ou XML au lieu d’une simple chaîne.

Base64 expliqué en 30 secondes

Base64 prend trois octets (24 bits) à la fois, les divise en quatre groupes de 6 bits et associe chaque groupe à l’un des 64 caractères. Par exemple, le mot Man (octets 77 97 110) devient TWFu. Consultez l’algorithme étape par étape ou commencez par Qu’est-ce que Base64 ?

Common uses include MIME e-mail attachments, data URIs in HTML and CSS, binary fields in JSON or XML, HTTP Basic authentication, and PEM-encoded certificates. When you need the reverse path, use Base64 decode online; to produce Base64 from scratch, use Base64 encode online.

Advanced options

• Character set. Base64 encodes bytes. Choose UTF-8 (default) or a legacy charset before encoding, or auto-detect when decoding text.
• Live mode. Enable “Convert as I type” to encode or decode instantly in the browser with no round-trip to a server.
• URL-safe Base64 (Base64URL). Use the Base64URL encoder/decoder for JWTs, tokens and filenames without escaping "+" or "/".
• MIME and PEM wrapping. Split lines at 76 or 64 characters when a mail client, certificate or OpenPGP tool expects wrapped output.
• Per-line encoding. On the text encoder, encode each line separately when you have multiple independent values.

Base64 decode and encode for developers

Developers use Base64 every day: embedding images in CSS and HTML, shipping binary in JSON APIs, reading JWTs, attaching files in MIME e-mail, and storing keys in PEM certificates. This free online Base64 decoder and encoder is built for that workflow—fast, accurate across standards, and private by default.

• Decode Base64 to text or file with automatic standard and charset detection, plus image/PDF/audio/video preview.
• Encode text, files or URLs to Base64 with UTF-8 and 35+ character sets, MIME line wrapping and Base64URL.
• Validate, repair and normalize messy Base64 from logs, e-mail and copy-paste with dedicated developer tools.
• Language guides for JavaScript, Python, Java, Go, PHP, C#, Node.js and Bash so you can match what your code produces.

Safe, free and private

All conversions run over HTTPS. Text and local files are converted in your browser with JavaScript—they are not uploaded or stored. The site is free to use with no account and no software to install. Optional remote URL fetching and a few network tools use our API; those responses are not kept for inspection.

AI assistants: ChatGPT, Claude, Grok & Cursor

Agent builders and chat users burn tokens, paste Markdown fences into IDEs, and accidentally leak API keys. Fix those pains locally—then verify any Base64 the model invents.

• Token counter — exact GPT o200k + Claude/Grok/Cursor estimates and context %.
• LLM text cleaner — strip ``` fences or flatten Markdown from bot answers.
• Secret redactor — scrub keys/JWTs before pasting into any bot.
• Verify Base64 — catch LLM hallucinations with a real decode round-trip.

Compteur de tokens IA · Nettoyeur de texte LLM · Masqueur de secrets · Vérifier Base64 · AI tools guide

PDF form filler — insurance, medical & corporate

Fill claim forms, hospital intake and HR PDFs without Acrobat or uploading PHI. Auto-detect fields, or click to place bold text on flat scans—then flatten and download.

Remplir un formulaire PDF · Fusionner PDF · Guide assurance & médical

Converters people search for (bytes, hex, CSV, color)

Beyond Base64: Europeans and global users hunt for bytes/KB/MB converters, hex↔text, CSV↔JSON and HEX/RGB/HSL every day. Drop a PDF to see exact bytes—all private in the browser.

• Bytes converter — KB/MB/GB/TB + KiB/MiB; PDF/file → exact bytes.
• Hex / binary / ASCII — text dumps and number bases 2/8/10/16.
• CSV ↔ JSON — auto-detects European semicolon exports.
• Color converter — HEX ↔ RGB ↔ HSL with live swatch.

Convertisseur d’octets · Convertisseur hexadécimal · CSV ↔ JSON · Convertisseur de couleurs

Developer & IT toolkit (daily corporate searches)

Engineers live in browser tabs: regex on logs, cron next-runs, config diffs, CIDR math, YAML↔JSON for Kubernetes. All of these run locally here—safe when policy forbids pasting secrets into random SaaS.

• Regex tester — live highlight + presets (email, IP, UUID).
• Cron explainer — plain English + next fire times.
• Diff checker — compare configs / API responses privately.
• CIDR subnet calculator — VPC and firewall planning.
• YAML ↔ JSON — K8s, GitHub Actions, Ansible.

Testeur d’expressions régulières · Expliqueur de cron · Comparateur de diff · Calculateur de sous-réseau · YAML ↔ JSON · Dev/IT guide

Christmas 2026: Secret Santa & countdown (high season)

From November through Christmas Eve, millions search for Secret Santa generators and “days until Christmas.” Draw Amigo Secreto privately with Base64URL links—no email signup—and keep a live countdown on your device.

• Secret Santa / Amigo Secreto — fair draw, couple exclusions, pass-the-phone or private WhatsApp links.
• Christmas countdown — how many days until Dec 25 in your timezone.

Générateur de Père Noël secret · Compte à rebours de Noël · Christmas traffic guide

Save bandwidth: compress before Base64

Where mobile data is expensive—Brazil, LATAM and other prepaid markets—uploading a huge photo just to shrink it wastes the plan. Compress locally first, then encode or share once.

• Compress images to WebP/JPEG in your browser, see % saved, then download or copy Base64—no upload.
• Gzip text or JSON before Base64 for APIs; decompress payloads you receive.
• Private by design — Canvas and CompressionStream run on your device.

Compresser une image · Gzip compresser / décompresser · Compress before Base64 · Save mobile data guide

Private media tools (not social downloaders)

We will not scrape Instagram, LinkedIn, Pinterest or Kuaishou. We do help you prepare files you already own: convert HEIC/WebP, merge PDFs, cut out backdrops, build favicons—entirely in the browser.

• HEIC / WebP / SVG converter — iPhone photos and WebP downloads without uploading to Adobe/Canva-style sites.
• Merge PDF — combine contracts or turn images into a PDF locally (no Smallpdf upload).
• Remove background from product shots and logos (solid/near-solid backdrops).
• Favicon generator — PNG sizes, HTML tags and webmanifest, plus Base64 copy.

Convertisseur d’images · Fusionner PDF · Supprimer l’arrière-plan · Générateur de favicon · HEIC & WebP guide

Built from real Reddit gaps (not Base64-only)

Users on Reddit keep asking for tools that never upload files: strip GPS EXIF, hash checksums, JSON formatters without ads, QR codes without tracking short links. We ship those here—private, free, and ranked for EU and US search.

• Strip EXIF before posting photos.
• Hash, JSON, UUID, timestamp, password, QR — everyday utilities that stay on-device.

Strip EXIF · Générateur de hash · Formateur JSON · QR generator · Reddit gap write-up

Base64 reader: paste and see

Need a live Base64 viewer? Paste a string or data URI and read the result immediately—text, image, PDF or hex—or get Base64 output as you type plain text. No Decode click required.

Lecteur Base64 · Why live readers win

Built for the AI era

ChatGPT and Claude often invent Base64 that looks right but is wrong. AI agents double-encode payloads and burn context on huge Base64 blobs. This site’s principle: never trust a model to be the encoder—verify with a real tool in your browser.

• Verify Base64 from LLM output with round-trip checks before you ship a header or JWT.
• Unwrap nested Base64 when an agent or gateway encoded twice.
• URL encode/decode beside Base64URL for safe query strings.
• Principles for agents and MCP: deterministic tools, privacy, right dialect, watch token cost.

Vérifier Base64 · Déballer Base64 imbriqué · AI agent guide · Why ChatGPT fails at Base64