Tools for your workflow

Calling the API

Manage API keys. Send your key in the Authorization: Bearer header. Never put keys in URLs or browser code. Free allowance: 30 requests per minute per key, 1,000 per UTC day per key and account. Keys expire after 90 days.

401 means missing or invalid credentials; 429 means a rate limit or allowance was reached (see Retry-After); 503 means execution is disabled or unavailable. Request bodies are limited to 16 KiB with a 2-second read deadline and 32 levels of nesting. JSON text is limited to 12,000 characters and formatted responses to 512 KiB. Query strings are limited to 4 KiB. Vercel handlers have a 5-second maximum duration.

GET endpoints accept query parameters. POST endpoints accept application/json. Successful requests return HTTP 200; invalid inputs return HTTP 400 with an error string. There is no API billing or MCP server. The public API has no uptime guarantee.

Browser interfaces calculate locally. API calls send the submitted input to the server for processing. Operational metrics exclude request bodies, query values and result contents.

Numeric calculations use JavaScript floating-point arithmetic. Percentage change from zero and zero running pace are undefined. Unit IDs must belong to the same category. Dates use IANA time zones and explicit daylight-saving disambiguation.

Webcam studio

Test your webcam, check lighting and frame rate, take photos and record video with optional microphone audio — all in one private browser workspace.

HTTPS and browser permission are required. Requested modes are preferences, not a supported-resolution certification. FPS and brightness depend on scene and browser conditions; no calibrated hardware quality, bandwidth or sound-pressure score is claimed. Microphone processing may affect levels. Photos follow Mirror; recordings retain the original feed. Maximum requested capture is 3840 × 2160 at 60 FPS; photos fit 3840 × 2160. Clips stop at two minutes and are discarded above 50 MB. One photo and one clip are retained in page memory; encoding can use additional memory. Hidden tabs stop capture. Recording formats and frame callbacks vary by browser.

Browser-only. No upload API or MCP endpoint is available for this tool.

Local SQL workbench

Query CSV and Parquet files, join local tables and export results with DuckDB in your browser.

30-second deadline including engine loading, 128 MB engine memory setting, 5,000 output rows and 2 million output characters. CSV types are inferred; CSV formula cells are escaped. No uploads or persistent database.

Browser-only. No upload API or MCP endpoint is available for this tool.

HAR performance viewer

Inspect local browser network logs for slow requests, timing phases and transferred bytes.

Unknown sizes remain unknown. SSL overlaps connection time; durations must not be summed into page-load time. URLs omit queries, fragments and credentials but paths may be sensitive.

Browser-only. No upload API or MCP endpoint is available for this tool.

Contact-card builder

Enter contact details or import a CSV and generate downloadable vCard contact files.

CSV up to 300,000 characters, 500 contacts and 500 characters per field. Full names occupy the given-name field; address fields, photos and deduplication are not supported.

Browser-only. No upload API or MCP endpoint is available for this tool.

Barbell plate-loading calculator

Find balanced plates per side from a target total, bar, collars and available inventory.

Up to 15 sizes, 20 pairs each and 2,000 target units. One pair means one plate per side. Units label values rather than converting them; no loading or training advice.

Browser-only. No upload API or MCP endpoint is available for this tool.

Recipe portion scaler

Scale ingredient quantities and fractions between original and target serving counts.

Up to 200 lines / 20,000 characters. Supports decimals, mixed numbers and common Unicode fractions. Ranges, quantity-free lines, unit conversion and cooking adjustments are unsupported.

Browser-only. No upload API or MCP endpoint is available for this tool.

MIDI file inspector

Inspect MIDI tracks, program changes, tempos and timed notes, then export structured JSON.

SMPTE and format 2 are unsupported. Default tempo is 120 BPM. Program numbers are 1–128; sounds depend on the synthesizer. Sustain pedal is not applied; unmatched notes retain null ends.

Browser-only. No upload API or MCP endpoint is available for this tool.

Audio spectrogram viewer

Visualise a short audio recording as frequency energy over time and export a labelled image.

FFT sizes 256–2,048, up to 600 frames. Browser decoding can resample audio; opposite-phase channels may cancel. Not calibrated sound pressure or a diagnostic tool.

Browser-only. No upload API or MCP endpoint is available for this tool.

STL model inspector

Rotate a local STL wireframe and inspect model dimensions and triangle counts.

STL has no encoded units; selection interprets coordinates. Preview samples at most 15,000 triangles. No watertightness, manifold or printability guarantee.

Browser-only. No upload API or MCP endpoint is available for this tool.

SVG path editor

Edit vector endpoints and control points, scale or move a path and export SVG with bounds.

Single path only; no full SVG markup, styles, layers or boolean operations. Arcs are approximated as cubic curves. Coordinates and transformation magnitude are bounded.

Browser-only. No upload API or MCP endpoint is available for this tool.

Keyboard event tester

Highlight pressed keys and inspect modifiers, repeats and a downloadable local keyboard test session.

Up to 1,000 events. Browser/OS shortcuts may never reach the page. Layout labels are illustrative; physical testing needs a person. Do not enter passwords. No background capture.

Browser-only. No upload API or MCP endpoint is available for this tool.

Local MongoDB-style workbench — CamaDB

Import JSON collections, browse documents, run supported CamaDB queries, preview edits and export JSON locally.

Workbenches support a documented subset of release operators, not full MongoDB compatibility. JSON depth 20, 20 pipeline stages and 30-second deadline. Identity is immutable; data is lost on reload.

Browser-only. No upload API or MCP endpoint is available for this tool.

PDF form filler

Fill existing PDF form fields and checkboxes, preview the result and download a missing-field report.

AcroForm only; no scanned forms, XFA, signatures or field creation. Latin font support; choice controls support supplied options. Existing signatures can be invalidated by editing. Required flags come from the PDF and are not a completeness guarantee.

Browser-only. No upload API or MCP endpoint is available for this tool.

Printable label sheets

Convert CSV records into printable PDF labels with adjustable dimensions, margins and overflow warnings.

Latin PDF font only. No mail-merge templates or printer calibration. Print at Actual size and test on plain paper; printer margins and scaling can affect alignment.

Browser-only. No upload API or MCP endpoint is available for this tool.

Image difference checker

Highlight changed pixels between two screenshots and measure the percentage changed.

Equal dimensions required. No alignment, perceptual similarity or semantic comparison. Compression, antialiasing and colour management can change pixels. Fully transparent RGB is ignored.

Browser-only. No upload API or MCP endpoint is available for this tool.

Barcode generator

Validate and render Code 128 and EAN-13 barcodes, then download SVG or PNG assets.

Code 128 supports printable ASCII only in this tool. Valid EAN checksums do not establish assigned product identifiers. Test final printed size and contrast with a scanner.

Browser-only. No upload API or MCP endpoint is available for this tool.

PDF watermarks & page numbers

Stamp review copies and number selected PDF pages with configurable placement and opacity.

Not redaction or copy protection. Rotated pages are rejected; normalize rotation first. Latin font only. Editing can invalidate digital signatures. Stamps may overlap existing content.

Browser-only. No upload API or MCP endpoint is available for this tool.

Sprite-sheet packer

Pack small graphics into an atlas PNG and download a frame-coordinate JSON index.

No rotation, trimming, extrusion, deduplication or optimal packing. Duplicate filenames are rejected. Animation and image metadata are omitted.

Browser-only. No upload API or MCP endpoint is available for this tool.

GPX route inspector

Inspect a route outline, distance and elevation, then download a simplified GPX without using a map service.

Simplification is spacing-based, not a maximum geometric-error guarantee. Export retains coordinates/elevation only, omitting timestamps, extensions and source metadata. Outline is approximate and may stretch across the antimeridian. No navigation or elevation correction.

Browser-only. No upload API or MCP endpoint is available for this tool.

Calendar conflict checker

Find overlapping events in imported ICS calendars within an inclusive date range and export a structured report.

Floating times and all-day dates are interpreted as UTC. Named zones require embedded VTIMEZONE. THISANDFUTURE and RDATE periods are rejected. Identical UID/start/end occurrences across imports are deduplicated. No remote calendar sync.

Browser-only. No upload API or MCP endpoint is available for this tool.

Tournament bracket maker

Seed entrants, handle byes and select winners in an exportable single-elimination bracket.

Single elimination only; no scores, double elimination, shared editing or saved tournaments. Printable SVG truncates long names while fixture JSON preserves them. Downloads capture the current state.

Browser-only. No upload API or MCP endpoint is available for this tool.

Guitar chord-diagram builder

Draw supplied guitar fingerings with custom tuning and export SVG or PNG diagrams.

Draws supplied fingerings without identifying or verifying chords. Six strings only, frets 0–24 within a five-fret span. Repeated fingers are separate dots, not barre lines.

Browser-only. No upload API or MCP endpoint is available for this tool.

Image contact-sheet maker

Create labelled thumbnail grids from photos and export PDF or JPEG sheets.

Thumbnails are resampled and JPEG is lossy. Transparency uses white; animation and source metadata are not retained. Labels are rasterised, not searchable PDF text.

Browser-only. No upload API or MCP endpoint is available for this tool.

Batch file renamer

Preview prefixes, numbering and literal replacements, then download renamed file copies in a ZIP.

No regex, recursive folder renaming or filesystem changes. ZIP stores files without compression. Portable filename restrictions may reject names accepted by your operating system.

Browser-only. No upload API or MCP endpoint is available for this tool.

Screenshot annotation

Add arrows, numbered markers and text to a screenshot, then export PNG privately in your browser.

No editable project file, redaction or automatic object detection. Text at an image edge can clip. Original metadata and animation are not retained.

Browser-only. No upload API or MCP endpoint is available for this tool.

ZIP creator & extractor

Bundle local files into a ZIP or inspect an archive and extract selected entries with explicit limits.

No encrypted, ZIP64, multipart, symlink or nested extraction. Non-ASCII paths require UTF-8 encoding. Unsafe or duplicate paths and oversized archives are rejected. File contents are not scanned for malware.

Browser-only. No upload API or MCP endpoint is available for this tool.

Subtitle timing fixer

Shift SRT or WebVTT subtitles and correct gradual timing drift, then export repaired timestamps.

No speech recognition, translation or media playback. Output timestamps must remain below 100 hours and end after start. Existing overlaps are preserved; unsupported or malformed timing lines are rejected.

Browser-only. No upload API or MCP endpoint is available for this tool.

Image palette extractor

Find representative image colours and copy HEX values or CSS custom properties.

Frequency sampling is approximate and can return similar colours. It does not identify semantic accents or guarantee contrast. Transparent images may produce no palette.

Browser-only. No upload API or MCP endpoint is available for this tool.

IPv4 subnet calculator

Convert CIDR prefixes and netmasks, calculate address ranges and check whether an IPv4 address belongs to a subnet.

IPv4 only. No network scanning, DNS lookup or reachability check. Usable counts do not account for provider reservations or routing policy.

Browser-only. No upload API or MCP endpoint is available for this tool.

Printable graph-paper generator

Generate A4 or US Letter graph, dotted or ruled paper as a printable PDF with custom spacing and colour.

No printer calibration, landscape layout or multi-page designs. Very light colours may not print clearly. Screen preview spacing is illustrative.

Browser-only. No upload API or MCP endpoint is available for this tool.

Screen pixel test

Show solid colours and a grid for manual monitor inspection, with optional fullscreen display.

No automatic hardware access, calibrated colour measurement, burn-in repair or flashing sequences. Browser fullscreen may be unavailable.

Browser-only. No upload API or MCP endpoint is available for this tool.

Random team generator

Shuffle a list of names into teams with balanced group sizes and copy the result.

Balances group size only, not skill, age or other attributes. Randomness does not guarantee preferred pairings. This is not an audited lottery system.

Browser-only. No upload API or MCP endpoint is available for this tool.

PDF splitter & page organiser

Extract, rotate and reorder PDF pages with local thumbnails. Download one PDF or split pages into a ZIP.

Unencrypted PDFs only; 25 MB and 200 pages. Export budget: 50 MB including ZIP overhead; splitting also requires input size times selected pages within 50 MB. Preview/export stop after 15 seconds and can be cancelled. Damaged files or unsupported form appearances may fail. Document-level metadata and signatures are not preserved.

Browser-only. No upload API or MCP endpoint is available for this tool.

Images to PDF

Turn photos and screenshots into a PDF, with ordering, page sizes and margins. Files stay on your device.

No OCR or searchable text. Animation becomes a still image and source metadata is removed. JPEG re-encoding is lossy.

Browser-only. No upload API or MCP endpoint is available for this tool.

QR code generator

Create QR codes for websites, text or Wi-Fi. Download PNG or SVG, with no account or redirect service.

Maximum 1,500 UTF-8 bytes. Wi-Fi support varies by scanner; WPA/WPA2, WEP and open networks are offered. Dense codes need larger print sizes.

Browser-only. No upload API or MCP endpoint is available for this tool.

Date & working-days calculator

Count days between dates or add and subtract days, with optional weekend exclusion.

Years 0001–9999. Add or subtract at most 100,000 days. No public holiday calendars or local business schedules.

Browser-only. No upload API or MCP endpoint is available for this tool.

Text comparison

Find added and removed words or lines, privately in your browser.

Plain text only; formatting and document files are not compared. Normalised mode changes displayed spacing. This is not a semantic comparison.

Browser-only. No upload API or MCP endpoint is available for this tool.

Image cropper & resizer

Crop, rotate and resize images to exact dimensions, then download individually or as a batch.

Same settings apply to every batch image. Metadata and animation are not retained. JPEG uses white behind transparency; JPEG and WebP use 90% quality.

Browser-only. No upload API or MCP endpoint is available for this tool.

Metronome

Keep time with tap tempo, accented beats and a clear visual pulse.

Requires Web Audio and a user gesture. Background operation is intentionally stopped; this is not a recording synchronisation clock.

Browser-only. No upload API or MCP endpoint is available for this tool.

CSV ↔ JSON converter

Convert CSV and flat JSON with headers, delimiter controls, previews and local downloads.

200,000 input characters, 800 KB file size, 10,000 rows and 100 columns. Headers must be unique and non-empty. Output is bounded to 2 million characters. Nested JSON is unsupported; JavaScript number precision applies.

Browser-only. No upload API or MCP endpoint is available for this tool.

Interval timer

Set work, rest and warm-up periods, with rounds, sound cues and a reusable local preset.

Work 1–3,600 seconds, rest 0–3,600 seconds, warm-up 0–600 seconds and 1–100 rounds. Browser suspension can delay cues. Storage and sound may be unavailable.

Browser-only. No upload API or MCP endpoint is available for this tool.

Colour contrast checker

Check text and background colours against WCAG AA and AAA contrast thresholds.

No transparency, gradients, background images or whole-page audit. The displayed ratio is rounded; classification uses full precision.

Browser-only. No upload API or MCP endpoint is available for this tool.

Running pace calculator

Convert minutes per mile to minutes per kilometre, or the other way around.

Constant pace is an assumption, not a race prediction.

Request

curl 'https://www.buddycode.tech/api/tools/pace?minutes=8&seconds=0&unit=mi' -H 'Authorization: Bearer YOUR_API_KEY'

Query parameters

[
  {
    "name": "minutes",
    "in": "query",
    "required": true,
    "schema": {
      "type": "integer",
      "minimum": 0,
      "maximum": 999
    }
  },
  {
    "name": "seconds",
    "in": "query",
    "required": true,
    "schema": {
      "type": "integer",
      "minimum": 0,
      "maximum": 59
    }
  },
  {
    "name": "unit",
    "in": "query",
    "required": false,
    "schema": {
      "type": "string",
      "enum": [
        "mi",
        "km"
      ],
      "default": "mi"
    }
  }
]

Example response

{
  "secondsPerKm": 298.2581722739203,
  "secondsPerMile": 480.00000000000006,
  "converted": {
    "seconds": 298.2581722739203,
    "formatted": "4:58",
    "unit": "min/km"
  },
  "finishTimes": [
    {
      "distance": "5K",
      "seconds": 1491.2908613696015,
      "formatted": "24:51"
    },
    {
      "distance": "10K",
      "seconds": 2982.581722739203,
      "formatted": "49:43"
    },
    {
      "distance": "10 miles",
      "seconds": 4800,
      "formatted": "1:20:00"
    },
    {
      "distance": "Half marathon",
      "seconds": 6292.501789549034,
      "formatted": "1:44:53"
    },
    {
      "distance": "Marathon",
      "seconds": 12585.003579098067,
      "formatted": "3:29:45"
    },
    {
      "distance": "50K",
      "seconds": 14912.908613696016,
      "formatted": "4:08:33"
    }
  ]
}

PDF merger

Bring your PDFs together. Choose the order, merge, and download.

2–20 files, 50 MB combined and 1,000 pages. Encrypted PDFs are unsupported; signatures and document-level bookmarks are not preserved.

Browser-only. No upload API or MCP endpoint is available for this tool.

Image compressor

Give your images a lighter footprint. Resize, adjust quality, and download.

20 MB and 40 megapixel input limits. Compression can increase file size. Animation and original metadata are not retained.

Browser-only. No upload API or MCP endpoint is available for this tool.

JSON formatter

Turn a wall of JSON into something you can read. Validate, format, and copy.

Up to 1 million characters. Duplicate keys retain the last value; large numbers may lose precision.

Request

curl 'https://www.buddycode.tech/api/tools/json' -H 'Authorization: Bearer YOUR_API_KEY' -H 'Content-Type: application/json' --data '{"text":"{\"hello\":1}","indent":2}'

Request body schema

{
  "type": "object",
  "properties": {
    "text": {
      "type": "string",
      "minLength": 1,
      "maxLength": 12000
    },
    "indent": {
      "type": "integer",
      "enum": [
        0,
        2,
        4
      ],
      "default": 2
    }
  },
  "required": [
    "text"
  ]
}

Example response

{
  "formatted": "{\n  \"hello\": 1\n}",
  "valid": true
}

Unit converter

Different units. Same measurement. Convert everyday quantities instantly.

Floating-point arithmetic; display uses up to 12 significant digits. US and Imperial volumes differ.

Request

curl 'https://www.buddycode.tech/api/tools/convert?value=1&category=Length&from=km&to=mi' -H 'Authorization: Bearer YOUR_API_KEY'

Query parameters

[
  {
    "name": "value",
    "in": "query",
    "required": true,
    "schema": {
      "type": "number"
    }
  },
  {
    "name": "category",
    "in": "query",
    "required": false,
    "schema": {
      "type": "string",
      "enum": [
        "Length",
        "Mass",
        "Temperature",
        "Volume",
        "Area",
        "Speed"
      ],
      "default": "Length"
    }
  },
  {
    "name": "from",
    "in": "query",
    "required": true,
    "schema": {
      "type": "string",
      "description": "Unit ID in the selected category; see /api/tools for all supported IDs."
    }
  },
  {
    "name": "to",
    "in": "query",
    "required": true,
    "schema": {
      "type": "string",
      "description": "Unit ID in the same category as from."
    }
  }
]

Example response

{
  "result": 0.621371192237334,
  "unit": "mi"
}

Time zone planner

Find your shared moment, wherever everyone happens to be.

Up to 12 destinations. The weekday 09:00–17:00 indicator excludes holidays and personal schedules.

Request

curl 'https://www.buddycode.tech/api/tools/time-zones' -H 'Authorization: Bearer YOUR_API_KEY' -H 'Content-Type: application/json' --data '{"local":"2026-09-14T14:00","zone":"Europe/London","zones":["America/New_York","Asia/Tokyo"],"disambiguation":"reject"}'

Request body schema

{
  "type": "object",
  "properties": {
    "local": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}T\\d{2}:\\d{2}$"
    },
    "zone": {
      "type": "string",
      "description": "Source IANA time zone"
    },
    "zones": {
      "type": "array",
      "minItems": 1,
      "maxItems": 12,
      "items": {
        "type": "string",
        "description": "Destination IANA time zone"
      }
    },
    "disambiguation": {
      "type": "string",
      "enum": [
        "reject",
        "earlier",
        "later"
      ],
      "default": "reject"
    }
  },
  "required": [
    "local",
    "zone",
    "zones"
  ]
}

Example response

{
  "instant": "2026-09-14T13:00:00Z",
  "source": "2026-09-14T14:00:00+01:00[Europe/London]",
  "times": [
    {
      "timeZone": "America/New_York",
      "date": "2026-09-14",
      "time": "09:00",
      "offset": "-04:00",
      "workingHours": true
    },
    {
      "timeZone": "Asia/Tokyo",
      "date": "2026-09-14",
      "time": "22:00",
      "offset": "+09:00",
      "workingHours": false
    }
  ]
}

Percentage calculator

Calculate percentages, percentage shares and percentage changes for free, directly in your browser.

Finite numbers only. Undefined divisions are rejected. Results use floating-point precision.

Request

curl 'https://www.buddycode.tech/api/tools/percentage?mode=of&a=20&b=150' -H 'Authorization: Bearer YOUR_API_KEY'

Query parameters

[
  {
    "name": "mode",
    "in": "query",
    "required": false,
    "schema": {
      "type": "string",
      "enum": [
        "of",
        "what",
        "change"
      ],
      "default": "of"
    }
  },
  {
    "name": "a",
    "in": "query",
    "required": true,
    "schema": {
      "type": "number"
    }
  },
  {
    "name": "b",
    "in": "query",
    "required": true,
    "schema": {
      "type": "number"
    }
  }
]

Example response

{
  "result": 30,
  "unit": "number"
}

Background noise test

Check microphone background noise before a call, compare changes and export a report. Audio stays on your device.

Not calibrated dB SPL or a hearing-safety assessment. Device processing, clipping and input changes can invalidate comparisons.

Browser-only. No upload API or MCP endpoint is available for this tool.

Guitar tuner

Tune your guitar online with chromatic pitch detection and eight tuning presets. Free, with microphone audio processed on your device.

Single notes from 55–1,200 Hz. Chords, background music and weak signals may not yield a reliable pitch.

Browser-only. No upload API or MCP endpoint is available for this tool.